first cut FPE, TupleHash, ParallelHash, and GCM-SIV

17 files changed, 2519 insertions, 1 deletions

diff --git a/crypto/src/crypto/IAlphabetMapper.cs b/crypto/src/crypto/IAlphabetMapper.cs
new file mode 100644
index 000000000..af63caafd
--- /dev/null
+++ b/crypto/src/crypto/IAlphabetMapper.cs
@@ -0,0 +1,32 @@
+using System;
+
+namespace Org.BouncyCastle.Crypto
+{
+/**
+ * Base interface for mapping from an alphabet to a set of indexes
+ * suitable for use with FPE.
+ */
+public interface IAlphabetMapper
+{
+    /// <summary>
+    /// Return the number of characters in the alphabet.
+    /// </summary>
+    /// <returns>the radix for the alphabet.</returns>
+    int Radix { get; }
+
+    /// <summary>
+    /// Return the passed in char[] as a byte array of indexes (indexes
+    /// can be more than 1 byte)
+    /// </summary>
+    /// <returns>an index array.</returns>
+    /// <param name="input">characters to be mapped.</param>   
+    byte[] ConvertToIndexes(char[] input);
+
+    /// <summary>
+    /// Return a char[] for this alphabet based on the indexes passed.
+    /// </summary>
+    /// <returns>an array of char corresponding to the index values.</returns>
+    /// <param name="input">input array of indexes.</param>   
+    char[] ConvertToChars(byte[] input);
+}
+}
diff --git a/crypto/src/crypto/digests/CSHAKEDigest.cs b/crypto/src/crypto/digests/CSHAKEDigest.cs
index 30d532089..c3b0b7068 100644
--- a/crypto/src/crypto/digests/CSHAKEDigest.cs
+++ b/crypto/src/crypto/digests/CSHAKEDigest.cs
@@ -44,6 +44,12 @@ namespace Org.BouncyCastle.Crypto.Digests
             }
         }
 
+        public CShakeDigest(CShakeDigest source)
+            : base(source)
+        {
+            this.diff = Arrays.Clone(source.diff);
+        }
+
         // bytepad in SP 800-185
         private void DiffPadAndAbsorb()
         {
diff --git a/crypto/src/crypto/digests/KeccakDigest.cs b/crypto/src/crypto/digests/KeccakDigest.cs
index 62a9e03b6..2da2e099e 100644
--- a/crypto/src/crypto/digests/KeccakDigest.cs
+++ b/crypto/src/crypto/digests/KeccakDigest.cs
@@ -28,7 +28,7 @@ namespace Org.BouncyCastle.Crypto.Digests
         protected byte[] dataQueue = new byte[192];
         protected int rate;
         protected int bitsInQueue;
-        protected int fixedOutputLength;
+        protected internal int fixedOutputLength;
         protected bool squeezing;
 
         public KeccakDigest()
diff --git a/crypto/src/crypto/digests/ParallelHash.cs b/crypto/src/crypto/digests/ParallelHash.cs
new file mode 100644
index 000000000..1e42d86ab
--- /dev/null
+++ b/crypto/src/crypto/digests/ParallelHash.cs
@@ -0,0 +1,210 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Digests
+{
+	/// <summary>
+    /// ParallelHash - a hash designed  to  support the efficient hashing of very long strings, by taking advantage,
+	/// of the parallelism available in modern processors with an optional XOF mode.
+	/// <para>
+	/// From NIST Special Publication 800-185 - SHA-3 Derived Functions:cSHAKE, KMAC, TupleHash and ParallelHash
+	/// </para>
+    /// </summary>
+	public class ParallelHash
+	    : IXof, IDigest
+	{
+	    private static readonly byte[] N_PARALLEL_HASH = Strings.ToByteArray("ParallelHash");
+
+	    private readonly CShakeDigest cshake;
+	    private readonly CShakeDigest compressor;
+	    private readonly int bitLength;
+	    private readonly int outputLength;
+	    private readonly int B;
+	    private readonly byte[] buffer;
+	    private readonly byte[] compressorBuffer;
+
+	    private bool firstOutput;
+	    private int nCount;
+	    private int bufOff;
+
+	    /**
+	     * Base constructor.
+	     *
+	     * @param bitLength bit length of the underlying SHAKE function, 128 or 256.
+	     * @param S the customization string - available for local use.
+	     * @param B the blocksize (in bytes) for hashing.
+	     */
+	    public ParallelHash(int bitLength, byte[] S, int B): this(bitLength, S, B, bitLength * 2)
+		{
+
+		}
+
+	    public ParallelHash(int bitLength, byte[] S, int B, int outputSize)
+	    {
+		this.cshake = new CShakeDigest(bitLength, N_PARALLEL_HASH, S);
+		this.compressor = new CShakeDigest(bitLength, new byte[0], new byte[0]);
+		this.bitLength = bitLength;
+		this.B = B;
+		this.outputLength = (outputSize + 7) / 8;
+		this.buffer = new byte[B];
+		this.compressorBuffer = new byte[bitLength * 2 / 8];
+
+		Reset();
+	    }
+
+	    public ParallelHash(ParallelHash source)
+	    {
+		this.cshake = new CShakeDigest(source.cshake);
+		this.compressor = new CShakeDigest(source.compressor);
+		this.bitLength = source.bitLength;
+		this.B = source.B;
+		this.outputLength = source.outputLength;
+		this.buffer = Arrays.Clone(source.buffer);
+		this.compressorBuffer = Arrays.Clone(source.compressorBuffer);
+	    }
+
+	    public string AlgorithmName
+	    {
+		    get { return "ParallelHash" + cshake.AlgorithmName.Substring(6); }
+	    }
+
+	    public int GetByteLength()
+	    {
+		return cshake.GetByteLength();
+	    }
+
+	    public int GetDigestSize()
+	    {
+		return outputLength;
+	    }
+
+	    public void Update(byte b)
+	    {
+		buffer[bufOff++] = b;
+		if (bufOff == buffer.Length)
+		{
+		    compress();
+		}
+	    }
+
+	    public void BlockUpdate(byte[] inBuf, int inOff, int len)
+	    {
+		len = System.Math.Max(0,  len);
+
+		//
+		// fill the current word
+		//
+		int i = 0;
+		if (bufOff != 0)
+		{
+		    while (i < len && bufOff != buffer.Length)
+		    {
+			buffer[bufOff++] = inBuf[inOff + i++];
+		    }
+
+		    if (bufOff == buffer.Length)
+		    {
+			compress();
+		    }
+		}
+
+		if (i < len)
+		{
+		    while (len - i > B)
+		    {
+			compress(inBuf, inOff + i, B);
+			i += B;
+		    }
+		}
+
+		while (i < len)
+		{
+		    Update(inBuf[inOff + i++]);
+		}
+	    }
+
+	    private void compress()
+	    {
+		compress(buffer, 0, bufOff);
+		bufOff = 0;
+	    }
+
+	    private void compress(byte[] buf, int offSet, int len)
+	    {
+		compressor.BlockUpdate(buf, offSet, len);
+		compressor.DoFinal(compressorBuffer, 0, compressorBuffer.Length);
+
+		cshake.BlockUpdate(compressorBuffer, 0, compressorBuffer.Length);
+
+		nCount++;
+	    }
+
+	    private void wrapUp(int outputSize)
+	    {
+		if (bufOff != 0)
+		{
+		    compress();
+		}
+		byte[] nOut = XofUtilities.RightEncode(nCount);
+		byte[] encOut = XofUtilities.RightEncode(outputSize * 8);
+
+		cshake.BlockUpdate(nOut, 0, nOut.Length);
+		cshake.BlockUpdate(encOut, 0, encOut.Length);
+
+		firstOutput = false;
+	    }
+
+	    public int DoFinal(byte[] outBuf, int outOff)
+	    {
+		if (firstOutput)
+		{
+		    wrapUp(outputLength);
+		}
+
+		int rv = cshake.DoFinal(outBuf, outOff, GetDigestSize());
+
+		Reset();
+
+		return rv;
+	    }
+
+	    public int DoFinal(byte[] outBuf, int outOff, int outLen)
+	    {
+		if (firstOutput)
+		{
+		    wrapUp(outputLength);
+		}
+		
+		int rv = cshake.DoFinal(outBuf, outOff, outLen);
+
+		Reset();
+
+		return rv;
+	    }
+
+	    public int DoOutput(byte[] outBuf, int outOff, int outLen)
+	    {
+		if (firstOutput)
+		{
+		    wrapUp(0);
+		}
+
+		return cshake.DoOutput(outBuf, outOff, outLen);
+	    }
+
+	    public void Reset()
+	    {
+		cshake.Reset();
+		Arrays.Clear(buffer);
+
+		byte[] hdr = XofUtilities.LeftEncode(B);
+		cshake.BlockUpdate(hdr, 0, hdr.Length);
+
+		nCount = 0;
+		bufOff = 0;
+		firstOutput = true;
+	    }
+	}
+}
diff --git a/crypto/src/crypto/digests/TupleHash.cs b/crypto/src/crypto/digests/TupleHash.cs
new file mode 100644
index 000000000..76bba3f94
--- /dev/null
+++ b/crypto/src/crypto/digests/TupleHash.cs
@@ -0,0 +1,134 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Digests
+{
+	/// <summary>
+    /// TupleHash - a hash designed  to  simply  hash  a  tuple  of  input  strings,  any  or  all  of  which  may  be  empty  strings,
+	/// in  an  unambiguous way with an optional XOF mode.
+	/// <para>
+	/// From NIST Special Publication 800-185 - SHA-3 Derived Functions:cSHAKE, KMAC, TupleHash and ParallelHash
+	/// </para>
+    /// </summary>
+	public class TupleHash
+	    : IXof, IDigest
+	{
+	    private static readonly byte[] N_TUPLE_HASH = Strings.ToByteArray("TupleHash");
+
+	    private readonly CShakeDigest cshake;
+	    private readonly int bitLength;
+	    private readonly int outputLength;
+
+	    private bool firstOutput;
+
+	    /**
+	     * Base constructor.
+	     *
+	     * @param bitLength bit length of the underlying SHAKE function, 128 or 256.
+	     * @param S         the customization string - available for local use.
+	     */
+	    public TupleHash(int bitLength, byte[] S): this(bitLength, S, bitLength * 2)
+		{
+
+		}
+
+	    public TupleHash(int bitLength, byte[] S, int outputSize)
+	    {
+		this.cshake = new CShakeDigest(bitLength, N_TUPLE_HASH, S);
+		this.bitLength = bitLength;
+		this.outputLength = (outputSize + 7) / 8;
+
+		Reset();
+	    }
+
+	    public TupleHash(TupleHash original)
+	    {
+		this.cshake = new CShakeDigest(original.cshake);
+		this.bitLength = cshake.fixedOutputLength;
+		this.outputLength = bitLength * 2 / 8;
+		this.firstOutput = original.firstOutput;
+	    }
+
+	    public string AlgorithmName
+	    {
+		   get { return "TupleHash" + cshake.AlgorithmName.Substring(6); }
+	    }
+
+	    public int GetByteLength()
+	    {
+		return cshake.GetByteLength();
+	    }
+
+	    public int GetDigestSize()
+	    {
+		return outputLength;
+	    }
+
+	    public void Update(byte b)
+	    {
+		byte[] bytes = XofUtilities.Encode(b);
+		cshake.BlockUpdate(bytes, 0, bytes.Length);
+	    }
+
+	    public void BlockUpdate(byte[] inBuf, int inOff, int len)
+	    {
+		byte[] bytes = XofUtilities.Encode(inBuf, inOff, len);
+		cshake.BlockUpdate(bytes, 0, bytes.Length);
+	    }
+
+	    private void wrapUp(int outputSize)
+	    {
+		byte[] encOut = XofUtilities.RightEncode(outputSize * 8);
+
+		cshake.BlockUpdate(encOut, 0, encOut.Length);
+
+		firstOutput = false;
+	    }
+
+	    public int DoFinal(byte[] outBuf, int outOff)
+	    {
+		if (firstOutput)
+		{
+		    wrapUp(GetDigestSize());
+		}
+		
+		int rv = cshake.DoFinal(outBuf, outOff, GetDigestSize());
+
+		Reset();
+
+		return rv;
+	    }
+
+	    public int DoFinal(byte[] outBuf, int outOff, int outLen)
+	    {
+		if (firstOutput)
+		{
+		    wrapUp(GetDigestSize());
+		}
+		
+		int rv = cshake.DoFinal(outBuf, outOff, outLen);
+
+		Reset();
+
+		return rv;
+	    }
+
+	    public int DoOutput(byte[] outBuf, int outOff, int outLen)
+	    {
+		if (firstOutput)
+		{
+		    wrapUp(0);
+		}
+
+		return cshake.DoOutput(outBuf, outOff, outLen);
+	    }
+
+	    public void Reset()
+	    {
+		cshake.Reset();
+		firstOutput = true;
+	    }
+	}
+}
diff --git a/crypto/src/crypto/digests/XofUtils.cs b/crypto/src/crypto/digests/XofUtils.cs
index 5c197e0e6..a4d6622b3 100644
--- a/crypto/src/crypto/digests/XofUtils.cs
+++ b/crypto/src/crypto/digests/XofUtils.cs
@@ -1,5 +1,7 @@
 using System;
 
+using Org.BouncyCastle.Utilities;
+
 namespace Org.BouncyCastle.Crypto.Digests
 {
     internal class XofUtilities
@@ -47,5 +49,19 @@ namespace Org.BouncyCastle.Crypto.Digests
 
             return b;
         }
+
+        internal static byte[] Encode(byte X)
+        {
+            return Arrays.Concatenate(LeftEncode(8), new byte[] { X });
+        }
+
+        internal static byte[] Encode(byte[] inBuf, int inOff, int len)
+        {
+            if (inBuf.Length == len)
+            {
+                return Arrays.Concatenate(LeftEncode(len * 8), inBuf);
+            }
+            return Arrays.Concatenate(LeftEncode(len * 8), Arrays.CopyOfRange(inBuf, inOff, inOff + len));
+        }
     }
 }
diff --git a/crypto/src/crypto/fpe/FpeEngine.cs b/crypto/src/crypto/fpe/FpeEngine.cs
new file mode 100644
index 000000000..6757bad3a
--- /dev/null
+++ b/crypto/src/crypto/fpe/FpeEngine.cs
@@ -0,0 +1,121 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Utilities;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Fpe
+{
+/**
+ * Base class for format-preserving encryption.
+ */
+public abstract class FpeEngine
+{
+    protected IBlockCipher baseCipher;
+
+    protected bool forEncryption;
+    protected FpeParameters fpeParameters;
+
+    protected FpeEngine(IBlockCipher baseCipher)
+    {
+        this.baseCipher = baseCipher;
+    }
+
+    /// <summary>
+    /// Process length bytes from inBuf, writing the output to outBuf.
+    /// </summary>
+    /// <returns>number of bytes output.</returns>
+    /// <param name="inBuf">input data.</param>  
+    /// <param name="inOff">offset in input data to start at.</param>  
+    /// <param name="length">number of bytes to process.</param>  
+    /// <param name="outBuf">destination buffer.</param>  
+    /// <param name="outOff">offset to start writing at in destination buffer.</param>  
+    public int ProcessBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff)
+    {
+        if (fpeParameters == null)
+        {
+            throw new InvalidOperationException("FPE engine not initialized");
+        }
+
+        if (length < 0)
+        {
+            throw new ArgumentException("input length cannot be negative");
+        }
+
+        if (inBuf == null || outBuf == null)
+        {
+            throw new NullReferenceException("buffer value is null");
+        }
+
+        if (inBuf.Length < inOff + length)
+        {
+            throw new DataLengthException("input buffer too short");
+        }
+
+        if (outBuf.Length < outOff + length)
+        {
+            throw new OutputLengthException("output buffer too short");
+        }
+
+        if (forEncryption)
+        {
+            return encryptBlock(inBuf, inOff, length, outBuf, outOff);
+        }
+        else
+        {
+            return decryptBlock(inBuf, inOff, length, outBuf, outOff);
+        }
+    }
+
+    protected static ushort[] toShortArray(byte[] buf)
+    {
+        if ((buf.Length & 1) != 0)
+        {
+            throw new ArgumentException("data must be an even number of bytes for a wide radix");
+        }
+
+        ushort[] rv = new ushort[buf.Length / 2];
+
+        for (int i = 0; i != rv.Length; i++)
+        {
+            rv[i] = Pack.BE_To_UInt16(buf, i * 2);
+        }
+
+        return rv;
+    }
+
+    protected static bool IsOverrideSet(string propName)
+    {
+        string propValue = Platform.GetEnvironmentVariable(propName);
+
+        return propValue == null || Platform.EqualsIgnoreCase("true", propValue);
+    }
+
+    protected static byte[] toByteArray(ushort[] buf)
+    {
+        byte[] rv = new byte[buf.Length * 2];
+
+        for (int i = 0; i != buf.Length; i++)
+        {
+            Pack.UInt16_To_BE(buf[i], rv, i * 2);
+        }
+
+        return rv;
+    }
+
+    /// <summary>
+    /// Initialize the FPE engine for encryption/decryption.
+    /// </summary>
+    /// <returns>number of bytes output.</returns>
+    /// <param name="forEncryption">true if initialising for encryption, false otherwise.</param>  
+    /// <param name="parameters ">the key and other parameters to use to set the engine up.</param>  
+    public abstract void Init(bool forEncryption, ICipherParameters parameters);
+
+    protected abstract int encryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff);
+
+    protected abstract int decryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff);
+}
+}
diff --git a/crypto/src/crypto/fpe/FpeFf1Engine.cs b/crypto/src/crypto/fpe/FpeFf1Engine.cs
new file mode 100644
index 000000000..8f34ef888
--- /dev/null
+++ b/crypto/src/crypto/fpe/FpeFf1Engine.cs
@@ -0,0 +1,70 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Crypto.Engines;
+using Org.BouncyCastle.Crypto.Parameters;
+
+namespace Org.BouncyCastle.Crypto.Fpe
+{
+public class FpeFf1Engine
+    : FpeEngine
+{
+    public FpeFf1Engine(): this(new AesEngine())
+    {
+    }
+
+    public FpeFf1Engine(IBlockCipher baseCipher): base(baseCipher)
+    {
+        if (IsOverrideSet(SP80038G.FPE_DISABLED)
+            || IsOverrideSet(SP80038G.FF1_DISABLED))
+        {
+            throw new InvalidOperationException("FF1 encryption disabled");
+        }
+    }
+
+    public override void Init(bool forEncryption, ICipherParameters parameters)
+    {
+        this.forEncryption = forEncryption;
+
+        this.fpeParameters = (FpeParameters)parameters;
+
+        baseCipher.Init(!fpeParameters.UseInverseFunction, fpeParameters.Key);
+    }
+
+    protected override int encryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff)
+    {
+        byte[] enc;
+
+        if (fpeParameters.Radix > 256)
+        {
+            enc = toByteArray(SP80038G.EncryptFF1w(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), toShortArray(inBuf), inOff, length / 2));
+        }
+        else
+        {
+            enc = SP80038G.EncryptFF1(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), inBuf, inOff, length);
+        }
+
+        Array.Copy(enc, 0, outBuf, outOff, length);
+
+        return length;
+    }
+
+    protected override int decryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff)
+    {
+        byte[] dec;
+
+        if (fpeParameters.Radix > 256)
+        {
+            dec = toByteArray(SP80038G.DecryptFF1w(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), toShortArray(inBuf), inOff, length / 2));
+        }
+        else
+        {
+            dec = SP80038G.DecryptFF1(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), inBuf, inOff, length);
+        }
+
+        Array.Copy(dec, 0, outBuf, outOff, length);
+
+        return length;
+    }
+}
+}
diff --git a/crypto/src/crypto/fpe/FpeFf3_1Engine.cs b/crypto/src/crypto/fpe/FpeFf3_1Engine.cs
new file mode 100644
index 000000000..480560bb2
--- /dev/null
+++ b/crypto/src/crypto/fpe/FpeFf3_1Engine.cs
@@ -0,0 +1,75 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Engines;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Fpe
+{
+public class FpeFf3_1Engine
+    : FpeEngine
+{
+    public FpeFf3_1Engine(): this(new AesEngine())
+    {
+    }
+
+    public FpeFf3_1Engine(IBlockCipher baseCipher): base(baseCipher)
+    {
+        if (IsOverrideSet(SP80038G.FPE_DISABLED))
+        {
+            throw new InvalidOperationException("FPE disabled");
+        }
+    }
+
+    public override void Init(bool forEncryption, ICipherParameters parameters)
+    {
+        this.forEncryption = forEncryption;
+
+        this.fpeParameters = (FpeParameters)parameters;
+
+        baseCipher.Init(!fpeParameters.UseInverseFunction, new KeyParameter(Arrays.Reverse(fpeParameters.Key.GetKey())));
+
+        if (fpeParameters.GetTweak().Length != 7)
+        {
+            throw new ArgumentException("tweak should be 56 bits");
+        }
+    }
+
+    protected override int encryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff)
+    {
+        byte[] enc;
+
+        if (fpeParameters.Radix > 256)
+        {
+            enc = toByteArray(SP80038G.EncryptFF3_1w(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), toShortArray(inBuf), inOff, length / 2));
+        }
+        else
+        {
+            enc = SP80038G.EncryptFF3_1(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), inBuf, inOff, length);
+        }
+
+        Array.Copy(enc, 0, outBuf, outOff, length);
+
+        return length;
+    }
+
+    protected override int decryptBlock(byte[] inBuf, int inOff, int length, byte[] outBuf, int outOff)
+    {
+        byte[] dec;
+
+        if (fpeParameters.Radix > 256)
+        {
+            dec = toByteArray(SP80038G.DecryptFF3_1w(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), toShortArray(inBuf), inOff, length / 2));
+        }
+        else
+        {
+            dec = SP80038G.DecryptFF3_1(baseCipher, fpeParameters.Radix, fpeParameters.GetTweak(), inBuf, inOff, length);
+        }
+
+        Array.Copy(dec, 0, outBuf, outOff, length);
+
+        return length;
+    }
+}
+}
diff --git a/crypto/src/crypto/fpe/SP80038G.cs b/crypto/src/crypto/fpe/SP80038G.cs
new file mode 100644
index 000000000..4ce89c9b2
--- /dev/null
+++ b/crypto/src/crypto/fpe/SP80038G.cs
@@ -0,0 +1,698 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Utilities;
+using Org.BouncyCastle.Math;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Fpe
+{
+    /*
+	 * SP800-38G Format-Preserving Encryption
+	 *
+	 * TODOs
+	 * - Initialize the cipher internally or externally?
+	 *     1. Algs 7-10 don't appear to require forward vs. inverse transform, although sample data is forward.
+	 *     2. Algs 9-10 specify reversal of the cipher key!
+	 * - Separate construction/initialization stage for "prerequisites"
+	 */
+    internal class SP80038G
+    {
+        internal static readonly string FPE_DISABLED = "Org.BouncyCastle.Fpe.Disable";
+        internal static readonly string FF1_DISABLED = "Org.BouncyCastle.Fpe.Disable_Ff1";
+
+        protected static readonly int BLOCK_SIZE = 16;
+        protected static readonly double LOG2 = System.Math.Log(2.0);
+        protected static readonly double TWO_TO_96 = System.Math.Pow(2, 96);
+
+        public static byte[] DecryptFF1(IBlockCipher cipher, int radix, byte[] tweak, byte[] buf, int off, int len)
+        {
+            checkArgs(cipher, true, radix, buf, off, len);
+
+            // Algorithm 8
+            int n = len;
+            int u = n / 2, v = n - u;
+
+            ushort[] A = toShort(buf, off, u);
+            ushort[] B = toShort(buf, off + u, v);
+
+            ushort[] rv = decFF1(cipher, radix, tweak, n, u, v, A, B);
+
+            return toByte(rv);
+        }
+
+        public static ushort[] DecryptFF1w(IBlockCipher cipher, int radix, byte[] tweak, ushort[] buf, int off, int len)
+        {
+            checkArgs(cipher, true, radix, buf, off, len);
+
+            // Algorithm 8
+            int n = len;
+            int u = n / 2, v = n - u;
+
+            ushort[] A = new ushort[u];
+            ushort[] B = new ushort[v];
+
+            Array.Copy(buf, off, A, 0, u);
+            Array.Copy(buf, off + u, B, 0, v);
+
+            return decFF1(cipher, radix, tweak, n, u, v, A, B);
+        }
+
+        private static ushort[] decFF1(IBlockCipher cipher, int radix, byte[] T, int n, int u, int v, ushort[] A, ushort[] B)
+        {
+            int t = T.Length;
+            int b = ((int)Ceil(System.Math.Log((double)radix) * (double)v / LOG2) + 7) / 8;
+            int d = (((b + 3) / 4) * 4) + 4;
+
+            byte[] P = calculateP_FF1(radix, (byte)u, n, t);
+
+            BigInteger bigRadix = BigInteger.ValueOf(radix);
+            BigInteger[] modUV = calculateModUV(bigRadix, u, v);
+
+            int m = u;
+
+            for (int i = 9; i >= 0; --i)
+            {
+                // i. - iv.
+                BigInteger y = calculateY_FF1(cipher, bigRadix, T, b, d, i, P, A);
+
+                // v.
+                m = n - m;
+                BigInteger modulus = modUV[i & 1];
+
+                // vi.
+                BigInteger c = num(bigRadix, B).Subtract(y).Mod(modulus);
+
+                // vii. - ix.
+                ushort[] C = B;
+                B = A;
+                A = C;
+                str(bigRadix, c, m, C, 0);
+            }
+
+            return Arrays.Concatenate(A, B);
+        }
+
+        public static byte[] DecryptFF3(IBlockCipher cipher, int radix, byte[] tweak64, byte[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak64.Length != 8)
+            {
+                throw new ArgumentException();
+            }
+
+            return implDecryptFF3(cipher, radix, tweak64, buf, off, len);
+        }
+
+        public static byte[] DecryptFF3_1(IBlockCipher cipher, int radix, byte[] tweak56, byte[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak56.Length != 7)
+            {
+                throw new ArgumentException("tweak should be 56 bits");
+            }
+
+            byte[] tweak64 = calculateTweak64_FF3_1(tweak56);
+
+            return implDecryptFF3(cipher, radix, tweak64, buf, off, len);
+        }
+
+        public static ushort[] DecryptFF3_1w(IBlockCipher cipher, int radix, byte[] tweak56, ushort[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak56.Length != 7)
+            {
+                throw new ArgumentException("tweak should be 56 bits");
+            }
+
+            byte[] tweak64 = calculateTweak64_FF3_1(tweak56);
+
+            return implDecryptFF3w(cipher, radix, tweak64, buf, off, len);
+        }
+
+        public static byte[] EncryptFF1(IBlockCipher cipher, int radix, byte[] tweak, byte[] buf, int off, int len)
+        {
+            checkArgs(cipher, true, radix, buf, off, len);
+
+            // Algorithm 7
+            int n = len;
+            int u = n / 2, v = n - u;
+
+            ushort[] A = toShort(buf, off, u);
+            ushort[] B = toShort(buf, off + u, v);
+
+            return toByte(encFF1(cipher, radix, tweak, n, u, v, A, B));
+        }
+
+        public static ushort[] EncryptFF1w(IBlockCipher cipher, int radix, byte[] tweak, ushort[] buf, int off, int len)
+        {
+            checkArgs(cipher, true, radix, buf, off, len);
+
+            // Algorithm 7
+            int n = len;
+            int u = n / 2, v = n - u;
+
+            ushort[] A = new ushort[u];
+            ushort[] B = new ushort[v];
+
+            Array.Copy(buf, off, A, 0, u);
+            Array.Copy(buf, off + u, B, 0, v);
+
+            return encFF1(cipher, radix, tweak, n, u, v, A, B);
+        }
+
+        private static ushort[] encFF1(IBlockCipher cipher, int radix, byte[] T, int n, int u, int v, ushort[] A, ushort[] B)
+        {
+            int t = T.Length;
+
+            int b = ((int)Ceil(System.Math.Log((double)radix) * (double)v / LOG2) + 7) / 8;
+            int d = (((b + 3) / 4) * 4) + 4;
+
+            byte[] P = calculateP_FF1(radix, (byte)u, n, t);
+
+            BigInteger bigRadix = BigInteger.ValueOf(radix);
+            BigInteger[] modUV = calculateModUV(bigRadix, u, v);
+
+            int m = v;
+
+            for (int i = 0; i < 10; ++i)
+            {
+                // i. - iv.
+                BigInteger y = calculateY_FF1(cipher, bigRadix, T, b, d, i, P, B);
+
+                // v.
+                m = n - m;
+                BigInteger modulus = modUV[i & 1];
+
+                // vi.
+                BigInteger c = num(bigRadix, A).Add(y).Mod(modulus);
+
+                // vii. - ix.
+                ushort[] C = A;
+                A = B;
+                B = C;
+                str(bigRadix, c, m, C, 0);
+            }
+
+            return Arrays.Concatenate(A, B);
+        }
+
+        public static byte[] EncryptFF3(IBlockCipher cipher, int radix, byte[] tweak64, byte[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak64.Length != 8)
+            {
+                throw new ArgumentException();
+            }
+
+            return implEncryptFF3(cipher, radix, tweak64, buf, off, len);
+        }
+
+        public static ushort[] EncryptFF3w(IBlockCipher cipher, int radix, byte[] tweak64, ushort[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak64.Length != 8)
+            {
+                throw new ArgumentException();
+            }
+
+            return implEncryptFF3w(cipher, radix, tweak64, buf, off, len);
+        }
+
+        public static ushort[] EncryptFF3_1w(IBlockCipher cipher, int radix, byte[] tweak56, ushort[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak56.Length != 7)
+            {
+                throw new ArgumentException("tweak should be 56 bits");
+            }
+            byte[] tweak64 = calculateTweak64_FF3_1(tweak56);
+
+            return EncryptFF3w(cipher, radix, tweak64, buf, off, len);
+        }
+
+        public static byte[] EncryptFF3_1(IBlockCipher cipher, int radix, byte[] tweak56, byte[] buf, int off, int len)
+        {
+            checkArgs(cipher, false, radix, buf, off, len);
+
+            if (tweak56.Length != 7)
+            {
+                throw new ArgumentException("tweak should be 56 bits");
+            }
+
+            byte[] tweak64 = calculateTweak64_FF3_1(tweak56);
+
+            return EncryptFF3(cipher, radix, tweak64, buf, off, len);
+        }
+
+        protected static BigInteger[] calculateModUV(BigInteger bigRadix, int u, int v)
+        {
+            BigInteger[] modUV = new BigInteger[2];
+            modUV[0] = bigRadix.Pow(u);
+            modUV[1] = modUV[0];
+            if (v != u)
+            {
+                modUV[1] = modUV[1].Multiply(bigRadix);
+            }
+            return modUV;
+        }
+
+        protected static byte[] calculateP_FF1(int radix, byte uLow, int n, int t)
+        {
+            byte[] P = new byte[BLOCK_SIZE];
+            P[0] = 1;
+            P[1] = 2;
+            P[2] = 1;
+
+            // Radix
+            P[3] = 0;
+            P[4] = (byte)(radix >> 8);
+            P[5] = (byte)radix;
+
+            P[6] = 10;
+            P[7] = uLow;
+            Pack.UInt32_To_BE((uint)n, P, 8);
+            Pack.UInt32_To_BE((uint)t, P, 12);
+            return P;
+        }
+
+        protected static byte[] calculateTweak64_FF3_1(byte[] tweak56)
+        {
+            byte[] tweak64 = new byte[8];
+            tweak64[0] = tweak56[0];
+            tweak64[1] = tweak56[1];
+            tweak64[2] = tweak56[2];
+            tweak64[3] = (byte)(tweak56[3] & 0xF0);
+            tweak64[4] = tweak56[4];
+            tweak64[5] = tweak56[5];
+            tweak64[6] = tweak56[6];
+            tweak64[7] = (byte)(tweak56[3] << 4);
+
+            return tweak64;
+        }
+
+        protected static BigInteger calculateY_FF1(IBlockCipher cipher, BigInteger bigRadix, byte[] T, int b, int d, int round, byte[] P, ushort[] AB)
+        {
+            int t = T.Length;
+
+            // i.
+            BigInteger numAB = num(bigRadix, AB);
+            byte[] bytesAB = BigIntegers.AsUnsignedByteArray(numAB);
+
+            int zeroes = -(t + b + 1) & 15;
+            byte[] Q = new byte[t + zeroes + 1 + b];
+            Array.Copy(T, 0, Q, 0, t);
+            Q[t + zeroes] = (byte)round;
+            Array.Copy(bytesAB, 0, Q, Q.Length - bytesAB.Length, bytesAB.Length);
+
+            // ii.
+            byte[] R = prf(cipher, Arrays.Concatenate(P, Q));
+
+            // iii.
+            byte[] sBlocks = R;
+            if (d > BLOCK_SIZE)
+            {
+                int sBlocksLen = (d + BLOCK_SIZE - 1) / BLOCK_SIZE;
+                sBlocks = new byte[sBlocksLen * BLOCK_SIZE];
+                Array.Copy(R, 0, sBlocks, 0, BLOCK_SIZE);
+
+                byte[] uint32 = new byte[4];
+                for (uint j = 1; j < sBlocksLen; ++j)
+                {
+                    int sOff = (int)(j * BLOCK_SIZE);
+                    Array.Copy(R, 0, sBlocks, sOff, BLOCK_SIZE);
+                    Pack.UInt32_To_BE(j, uint32, 0);
+                    xor(uint32, 0, sBlocks, sOff + BLOCK_SIZE - 4, 4);
+                    cipher.ProcessBlock(sBlocks, sOff, sBlocks, sOff);
+                }
+            }
+
+            // iv.
+            return num(sBlocks, 0, d);
+        }
+
+        protected static BigInteger calculateY_FF3(IBlockCipher cipher, BigInteger bigRadix, byte[] T, int wOff, uint round, ushort[] AB)
+        {
+            // ii.
+            byte[] P = new byte[BLOCK_SIZE];
+            Pack.UInt32_To_BE(round, P, 0);
+            xor(T, wOff, P, 0, 4);
+            BigInteger numAB = num(bigRadix, AB);
+
+            byte[] bytesAB = BigIntegers.AsUnsignedByteArray(numAB);
+
+            if ((P.Length - bytesAB.Length) < 4)  // to be sure...
+            {
+                throw new InvalidOperationException("input out of range");
+            }
+            Array.Copy(bytesAB, 0, P, P.Length - bytesAB.Length, bytesAB.Length);
+
+            // iii.
+            rev(P);
+            cipher.ProcessBlock(P, 0, P, 0);
+            rev(P);
+            byte[] S = P;
+
+            // iv.
+            return num(S, 0, S.Length);
+        }
+
+        protected static void checkArgs(IBlockCipher cipher, bool isFF1, int radix, ushort[] buf, int off, int len)
+        {
+            checkCipher(cipher);
+            if (radix < 2 || radix > (1 << 16))
+            {
+                throw new ArgumentException();
+            }
+            checkData(isFF1, radix, buf, off, len);
+        }
+
+        protected static void checkArgs(IBlockCipher cipher, bool isFF1, int radix, byte[] buf, int off, int len)
+        {
+            checkCipher(cipher);
+            if (radix < 2 || radix > (1 << 8))
+            {
+                throw new ArgumentException();
+            }
+            checkData(isFF1, radix, buf, off, len);
+        }
+
+        protected static void checkCipher(IBlockCipher cipher)
+        {
+            if (BLOCK_SIZE != cipher.GetBlockSize())
+            {
+                throw new ArgumentException();
+            }
+        }
+
+        protected static void checkData(bool isFF1, int radix, ushort[] buf, int off, int len)
+        {
+            checkLength(isFF1, radix, len);
+            for (int i = 0; i < len; ++i)
+            {
+                int b = buf[off + i] & 0xFFFF;
+                if (b >= radix)
+                {
+                    throw new ArgumentException("input data outside of radix");
+                }
+            }
+        }
+
+        protected static void checkData(bool isFF1, int radix, byte[] buf, int off, int len)
+        {
+            checkLength(isFF1, radix, len);
+            for (int i = 0; i < len; ++i)
+            {
+                int b = buf[off + i] & 0xFF;
+                if (b >= radix)
+                {
+                    throw new ArgumentException("input data outside of radix");
+                }
+            }
+        }
+
+        private static void checkLength(bool isFF1, int radix, int len)
+        {
+            if (len < 2 || System.Math.Pow(radix, len) < 1000000)
+            {
+                throw new ArgumentException("input too short");
+            }
+            if (!isFF1)
+            {
+                int maxLen = 2 * (int)(System.Math.Floor(System.Math.Log(TWO_TO_96) / System.Math.Log(radix)));
+                if (len > maxLen)
+                {
+                    throw new ArgumentException("maximum input length is " + maxLen);
+                }
+            }
+        }
+
+        protected static byte[] implDecryptFF3(IBlockCipher cipher, int radix, byte[] tweak64, byte[] buf, int off, int len)
+        {
+            // Algorithm 10
+            byte[] T = tweak64;
+            int n = len;
+            int v = n / 2, u = n - v;
+
+            ushort[] A = toShort(buf, off, u);
+            ushort[] B = toShort(buf, off + u, v);
+
+            ushort[] rv = decFF3_1(cipher, radix, T, n, v, u, A, B);
+
+            return toByte(rv);
+        }
+
+        protected static ushort[] implDecryptFF3w(IBlockCipher cipher, int radix, byte[] tweak64, ushort[] buf, int off, int len)
+        {
+            // Algorithm 10
+            byte[] T = tweak64;
+            int n = len;
+            int v = n / 2, u = n - v;
+
+            ushort[] A = new ushort[u];
+            ushort[] B = new ushort[v];
+
+            Array.Copy(buf, off, A, 0, u);
+            Array.Copy(buf, off + u, B, 0, v);
+
+            return decFF3_1(cipher, radix, T, n, v, u, A, B);
+        }
+
+        private static ushort[] decFF3_1(IBlockCipher cipher, int radix, byte[] T, int n, int v, int u, ushort[] A, ushort[] B)
+        {
+            BigInteger bigRadix = BigInteger.ValueOf(radix);
+            BigInteger[] modVU = calculateModUV(bigRadix, v, u);
+
+            int m = u;
+
+            // Note we keep A, B in reverse order throughout
+            rev(A);
+            rev(B);
+
+            for (int i = 7; i >= 0; --i)
+            {
+                // i.
+                m = n - m;
+                BigInteger modulus = modVU[1 - (i & 1)];
+                int wOff = 4 - ((i & 1) * 4);
+
+                // ii. - iv.
+                BigInteger y = calculateY_FF3(cipher, bigRadix, T, wOff, (uint)i, A);
+
+                // v.
+                BigInteger c = num(bigRadix, B).Subtract(y).Mod(modulus);
+
+                // vi. - viii.
+                ushort[] C = B;
+                B = A;
+                A = C;
+                str(bigRadix, c, m, C, 0);
+            }
+
+            rev(A);
+            rev(B);
+
+            return Arrays.Concatenate(A, B);
+        }
+
+        protected static byte[] implEncryptFF3(IBlockCipher cipher, int radix, byte[] tweak64, byte[] buf, int off, int len)
+        {
+            // Algorithm 9
+            byte[] T = tweak64;
+            int n = len;
+            int v = n / 2, u = n - v;
+
+            ushort[] A = toShort(buf, off, u);
+            ushort[] B = toShort(buf, off + u, v);
+
+            ushort[] rv = encFF3_1(cipher, radix, T, n, v, u, A, B);
+
+            return toByte(rv);
+        }
+
+        protected static ushort[] implEncryptFF3w(IBlockCipher cipher, int radix, byte[] tweak64, ushort[] buf, int off, int len)
+        {
+            // Algorithm 9
+            byte[] T = tweak64;
+            int n = len;
+            int v = n / 2, u = n - v;
+
+            ushort[] A = new ushort[u];
+            ushort[] B = new ushort[v];
+
+            Array.Copy(buf, off, A, 0, u);
+            Array.Copy(buf, off + u, B, 0, v);
+
+            return encFF3_1(cipher, radix, T, n, v, u, A, B);
+        }
+
+        private static ushort[] encFF3_1(IBlockCipher cipher, int radix, byte[] t, int n, int v, int u, ushort[] a, ushort[] b)
+        {
+            BigInteger bigRadix = BigInteger.ValueOf(radix);
+            BigInteger[] modVU = calculateModUV(bigRadix, v, u);
+
+            int m = v;
+
+            // Note we keep A, B in reverse order throughout
+            rev(a);
+            rev(b);
+
+            for (uint i = 0; i < 8; ++i)
+            {
+                // i.
+                m = n - m;
+                BigInteger modulus = modVU[1 - (i & 1)];
+                int wOff = 4 - (int)((i & 1) * 4);
+
+                // ii. - iv.
+                BigInteger y = calculateY_FF3(cipher, bigRadix, t, wOff, i, b);
+
+                // v.
+                BigInteger c = num(bigRadix, a).Add(y).Mod(modulus);
+
+                // vi. - viii.
+                ushort[] C = a;
+                a = b;
+                b = C;
+                str(bigRadix, c, m, C, 0);
+            }
+
+            rev(a);
+            rev(b);
+
+            return Arrays.Concatenate(a, b);
+        }
+
+        protected static BigInteger num(byte[] buf, int off, int len)
+        {
+            return new BigInteger(1, Arrays.CopyOfRange(buf, off, off + len));
+        }
+
+        protected static BigInteger num(BigInteger R, ushort[] x)
+        {
+            BigInteger result = BigInteger.Zero;
+            for (int i = 0; i < x.Length; ++i)
+            {
+                result = result.Multiply(R).Add(BigInteger.ValueOf(x[i] & 0xFFFF));
+            }
+            return result;
+        }
+
+        protected static byte[] prf(IBlockCipher c, byte[] x)
+        {
+            if ((x.Length % BLOCK_SIZE) != 0)
+            {
+                throw new ArgumentException();
+            }
+
+            int m = x.Length / BLOCK_SIZE;
+            byte[] y = new byte[BLOCK_SIZE];
+
+            for (int i = 0; i < m; ++i)
+            {
+                xor(x, i * BLOCK_SIZE, y, 0, BLOCK_SIZE);
+                c.ProcessBlock(y, 0, y, 0);
+            }
+
+            return y;
+        }
+
+        //    protected static void rev(byte[] x, int xOff, byte[] y, int yOff, int len)
+        //    {
+        //        for (int i = 1; i <= len; ++i)
+        //        {
+        //            y[yOff + len - i] = x[xOff + i - 1];
+        //        }
+        //    }
+
+        protected static void rev(byte[] x)
+        {
+            int half = x.Length / 2, end = x.Length - 1;
+            for (int i = 0; i < half; ++i)
+            {
+                byte tmp = x[i];
+                x[i] = x[end - i];
+                x[end - i] = tmp;
+            }
+        }
+
+        protected static void rev(ushort[] x)
+        {
+            int half = x.Length / 2, end = x.Length - 1;
+            for (int i = 0; i < half; ++i)
+            {
+                ushort tmp = x[i];
+                x[i] = x[end - i];
+                x[end - i] = tmp;
+            }
+        }
+
+        protected static void str(BigInteger R, BigInteger x, int m, ushort[] output, int off)
+        {
+            if (x.SignValue < 0)
+            {
+                throw new ArgumentException();
+            }
+            for (int i = 1; i <= m; ++i)
+            {
+                BigInteger[] qr = x.DivideAndRemainder(R);
+                output[off + m - i] = (ushort)qr[1].IntValue;
+                x = qr[0];
+            }
+            if (x.SignValue != 0)
+            {
+                throw new ArgumentException();
+            }
+        }
+
+        protected static void xor(byte[] x, int xOff, byte[] y, int yOff, int len)
+        {
+            for (int i = 0; i < len; ++i)
+            {
+                y[yOff + i] ^= x[xOff + i];
+            }
+        }
+
+        private static byte[] toByte(ushort[] buf)
+        {
+            byte[] s = new byte[buf.Length];
+
+            for (int i = 0; i != s.Length; i++)
+            {
+                s[i] = (byte)buf[i];
+            }
+
+            return s;
+        }
+
+        private static ushort[] toShort(byte[] buf, int off, int len)
+        {
+            ushort[] s = new ushort[len];
+
+            for (int i = 0; i != s.Length; i++)
+            {
+                s[i] = (ushort)(buf[off + i] & 0xFF);
+            }
+
+            return s;
+        }
+
+	private static int Ceil(double v)
+	{
+		int rv = (int)v;
+		if ((double)rv < v)
+                {
+			return rv + 1;
+                }
+                return rv;
+	}
+    }
+}
diff --git a/crypto/src/crypto/modes/GcmSivBlockCipher.cs b/crypto/src/crypto/modes/GcmSivBlockCipher.cs
new file mode 100644
index 000000000..a45e5ec06
--- /dev/null
+++ b/crypto/src/crypto/modes/GcmSivBlockCipher.cs
@@ -0,0 +1,963 @@
+using System;
+using System.Diagnostics;
+
+using Org.BouncyCastle.Utilities.IO;
+using Org.BouncyCastle.Crypto.Macs;
+using Org.BouncyCastle.Crypto.Engines;
+using Org.BouncyCastle.Crypto.Modes.Gcm;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Utilities;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Modes
+{
+	/**
+	 * GCM-SIV Mode.
+	 * <p>It should be noted that the specified limit of 2<sup>36</sup> bytes is not supported. This is because all bytes are
+	 * cached in a <b>ByteArrayOutputStream</b> object (which has a limit of a little less than 2<sup>31</sup> bytes),
+	 * and are output on the <b>DoFinal</b>() call (which can only process a maximum of 2<sup>31</sup> bytes).</p>
+	 * <p>The practical limit of 2<sup>31</sup> - 24 bytes is policed, and attempts to breach the limit will be rejected</p>
+	 * <p>In order to properly support the higher limit, an extended form of <b>ByteArrayOutputStream</b> would be needed
+	 * which would use multiple arrays to store the data. In addition, a new <b>doOutput</b> method would be required (similar
+	 * to that in <b>XOF</b> digests), which would allow the data to be output over multiple calls. Alternatively an extended
+	 * form of <b>ByteArrayInputStream</b> could be used to deliver the data.</p>
+	 */
+	public class GcmSivBlockCipher
+		 : IAeadBlockCipher 
+	{
+	     /**
+	      * The buffer length.
+	      */
+	     private static readonly int BUFLEN = 16;
+
+	     /**
+	      * The halfBuffer length.
+	      */
+	     private static readonly int HALFBUFLEN = BUFLEN >> 1;
+
+	     /**
+	      * The nonce length.
+	      */
+	     private static readonly int NONCELEN = 12;
+
+	     /**
+	      * The maximum data length (AEAD/PlainText). Due to implementation constraints this is restricted to the maximum
+	      * array length (https://programming.guide/java/array-maximum-length.html) minus the BUFLEN to allow for the MAC
+	      */
+	     private static readonly int MAX_DATALEN = Int32.MaxValue - 8 - BUFLEN;
+
+	     /**
+	      * The top bit mask.
+	      */
+	     private static readonly byte MASK = (byte) 0x80;
+
+	     /**
+	      * The addition constant.
+	      */
+	     private static readonly byte ADD = (byte) 0xE1;
+
+	     /**
+	      * The initialisation flag.
+	      */
+	     private static readonly int INIT = 1;
+
+	     /**
+	      * The aeadComplete flag.
+	      */
+	     private static readonly int AEAD_COMPLETE = 2;
+
+	     /**
+	      * The cipher.
+	      */
+	     private readonly IBlockCipher theCipher;
+
+	     /**
+	      * The multiplier.
+	      */
+	     private readonly IGcmMultiplier theMultiplier;
+
+	     /**
+	      * The gHash buffer.
+	      */
+	     internal readonly byte[] theGHash = new byte[BUFLEN];
+
+	     /**
+	      * The reverse buffer.
+	      */
+	     internal readonly byte[] theReverse = new byte[BUFLEN];
+
+	     /**
+	      * The aeadHasher.
+	      */
+	     private readonly GCMSIVHasher theAEADHasher;
+
+	     /**
+	      * The dataHasher.
+	      */
+	     private readonly GCMSIVHasher theDataHasher;
+
+	     /**
+	      * The plainDataStream.
+	      */
+	     private GCMSIVCache thePlain;
+
+	     /**
+	      * The encryptedDataStream (decryption only).
+	      */
+	     private GCMSIVCache theEncData;
+
+	     /**
+	      * Are we encrypting?
+	      */
+	     private bool forEncryption;
+
+	     /**
+	      * The initialAEAD.
+	      */
+	     private byte[] theInitialAEAD;
+
+	     /**
+	      * The nonce.
+	      */
+	     private byte[] theNonce;
+
+	     /**
+	      * The flags.
+	      */
+	     private int theFlags;
+
+	     /**
+	      * Constructor.
+	      */
+	     public GcmSivBlockCipher(): this(new AesEngine())
+	     {
+		 
+	     }
+
+	     /**
+	      * Constructor.
+	      * @param pCipher the underlying cipher
+	      */
+	     public GcmSivBlockCipher(IBlockCipher pCipher): this(pCipher, new Tables4kGcmMultiplier())
+	     {
+		 
+	     }
+
+	     /**
+	      * Constructor.
+	      * @param pCipher the underlying cipher
+	      * @param pMultiplier the multiplier
+	      */
+	     public GcmSivBlockCipher(IBlockCipher pCipher,
+				      IGcmMultiplier pMultiplier)
+	     {
+		 /* Ensure that the cipher is the correct size */
+		 if (pCipher.GetBlockSize() != BUFLEN)
+		 {
+		     throw new ArgumentException("Cipher required with a block size of " + BUFLEN + ".");
+		 }
+
+		 /* Store parameters */
+		 theCipher = pCipher;
+		 theMultiplier = pMultiplier;
+
+		 /* Create the hashers */
+		 theAEADHasher = new GCMSIVHasher(this);
+		 theDataHasher = new GCMSIVHasher(this);
+	     }
+
+	     public IBlockCipher GetUnderlyingCipher()
+	     {
+		 return theCipher;
+	     }
+
+        public virtual int GetBlockSize()
+        {
+            return theCipher.GetBlockSize();
+        }
+
+	     public void Init(bool pEncrypt,
+			      ICipherParameters cipherParameters)
+	     {
+		 /* Set defaults */
+		 byte[] myInitialAEAD = null;
+		 byte[] myNonce = null;
+		 KeyParameter myKey = null;
+
+		 /* Access parameters */
+		 if (cipherParameters is AeadParameters)
+		 {
+		     AeadParameters myAEAD = (AeadParameters) cipherParameters;
+		     myInitialAEAD = myAEAD.GetAssociatedText();
+		     myNonce = myAEAD.GetNonce();
+		     myKey = myAEAD.Key;
+		 }
+		 else if (cipherParameters is ParametersWithIV)
+		 {
+		     ParametersWithIV myParms = (ParametersWithIV) cipherParameters;
+		     myNonce = myParms.GetIV();
+		     myKey = (KeyParameter) myParms.Parameters;
+		 }
+		 else
+		 {
+		     throw new ArgumentException("invalid parameters passed to GCM_SIV");
+		 }
+
+		 /* Check nonceSize */
+		 if (myNonce == null || myNonce.Length != NONCELEN)
+		 {
+		     throw new ArgumentException("Invalid nonce");
+		 }
+
+		 /* Check keysize */
+		 if (myKey == null)
+		 {
+		     throw new ArgumentException("Invalid key");
+		 }
+		 
+		 byte[] k = myKey.GetKey();
+
+		 if (k.Length != BUFLEN
+			 && k.Length != (BUFLEN << 1))
+		 {
+		     throw new ArgumentException("Invalid key");
+		 }
+
+		 /* Reset details */
+		 forEncryption = pEncrypt;
+		 theInitialAEAD = myInitialAEAD;
+		 theNonce = myNonce;
+
+		 /* Initialise the keys */
+		 deriveKeys(myKey);
+		 resetStreams();
+	     }
+
+	     public string AlgorithmName
+	     {
+		 	get { return theCipher.AlgorithmName + "-GCM-SIV"; }
+	     }
+
+	     /**
+	      * check AEAD status.
+	      * @param pLen the aeadLength
+	      */
+	     private void checkAEADStatus(int pLen)
+	     {
+		 /* Check we are initialised */
+		 if ((theFlags & INIT) == 0)
+		 {
+		     throw new InvalidOperationException("Cipher is not initialised");
+		 }
+
+		 /* Check AAD is allowed */
+		 if ((theFlags & AEAD_COMPLETE) != 0)
+		 {
+		     throw new InvalidOperationException("AEAD data cannot be processed after ordinary data");
+		 }
+
+		 /* Make sure that we haven't breached AEAD data limit */
+		 if ((long)theAEADHasher.getBytesProcessed() + Int64.MinValue
+		      > (MAX_DATALEN - pLen) + Int64.MinValue)
+		 {
+		     throw new InvalidOperationException("AEAD byte count exceeded");
+		 }
+	     }
+
+	     /**
+	      * check status.
+	      * @param pLen the dataLength
+	      */
+	     private void checkStatus(int pLen)
+	     {
+		 /* Check we are initialised */
+		 if ((theFlags & INIT) == 0)
+		 {
+		     throw new InvalidOperationException("Cipher is not initialised");
+		 }
+
+		 /* Complete the AEAD section if this is the first data */
+		 if ((theFlags & AEAD_COMPLETE) == 0)
+		 {
+		     theAEADHasher.completeHash();
+		     theFlags |= AEAD_COMPLETE;
+		 }
+
+		 /* Make sure that we haven't breached data limit */
+		 long dataLimit = MAX_DATALEN;
+		 long currBytes = thePlain.Length;
+		 if (!forEncryption)
+		 {
+		     dataLimit += BUFLEN;
+		     currBytes = theEncData.Length;
+		 }
+		 if (currBytes + System.Int64.MinValue
+		       > (dataLimit - pLen) + System.Int64.MinValue)
+		 {
+		     throw new InvalidOperationException("byte count exceeded");
+		 }
+	     }
+
+	     public void ProcessAadByte(byte pByte)
+	     {
+		 /* Check that we can supply AEAD */
+		 checkAEADStatus(1);
+
+		 /* Process the aead */
+		 theAEADHasher.updateHash(pByte);
+	     }
+
+	     public void ProcessAadBytes(byte[] pData,
+					 int pOffset,
+					 int pLen)
+	     {
+		 /* Check that we can supply AEAD */
+		 checkAEADStatus(pLen);
+
+		 /* Check input buffer */
+		 checkBuffer(pData, pOffset, pLen, false);
+
+		 /* Process the aead */
+		 theAEADHasher.updateHash(pData, pOffset, pLen);
+	     }
+
+	     public int ProcessByte(byte pByte,
+				    byte[] pOutput,
+				    int pOutOffset)
+	     {
+		 /* Check that we have initialised */
+		 checkStatus(1);
+
+		 /* Store the data */
+		 if (forEncryption)
+		 {
+		     thePlain.WriteByte(pByte);
+		     theDataHasher.updateHash(pByte);
+		 }
+		 else
+		 {
+		     theEncData.WriteByte(pByte);
+		 }
+
+		 /* No data returned */
+		 return 0;
+	     }
+
+	     public int ProcessBytes(byte[] pData,
+				     int pOffset,
+				     int pLen,
+				     byte[] pOutput,
+				     int pOutOffset)
+	     {
+		 /* Check that we have initialised */
+		 checkStatus(pLen);
+
+		 /* Check input buffer */
+		 checkBuffer(pData, pOffset, pLen, false);
+
+		 /* Store the data */
+		 if (forEncryption)
+		 {
+		     thePlain.Write(pData, pOffset, pLen);
+		     theDataHasher.updateHash(pData, pOffset, pLen);
+		 }
+		 else
+		 {
+		     theEncData.Write(pData, pOffset, pLen);
+		 }
+
+		 /* No data returned */
+		 return 0;
+	     }
+
+	     public int DoFinal(byte[] pOutput,
+				int pOffset)
+	     {
+		 /* Check that we have initialised */
+		 checkStatus(0);
+
+		 /* Check output buffer */
+		 checkBuffer(pOutput, pOffset, GetOutputSize(0), true);
+
+		 /* If we are encrypting */
+		 if (forEncryption)
+		 {
+		     /* Derive the tag */
+		     byte[] myTag = calculateTag();
+
+		     /* encrypt the plain text */
+		     int myDataLen = BUFLEN + encryptPlain(myTag, pOutput, pOffset);
+
+		     /* Add the tag to the output */
+		     Array.Copy(myTag, 0, pOutput, pOffset + thePlain.Length, BUFLEN);
+
+		     /* Reset the streams */
+		     resetStreams();
+		     return myDataLen;
+
+		     /* else we are decrypting */
+		 }
+		 else
+		 {
+		     /* decrypt to plain text */
+		     decryptPlain();
+
+		     /* Release plain text */
+		     int myDataLen = (int)thePlain.Length;
+		     byte[] mySrc = thePlain.GetBuffer();
+		     Array.Copy(mySrc, 0, pOutput, pOffset, myDataLen);
+
+		     /* Reset the streams */
+		     resetStreams();
+		     return myDataLen;
+		 }
+	     }
+
+	     public byte[] GetMac()
+	     {
+		 throw new InvalidOperationException();
+	     }
+
+	     public int GetUpdateOutputSize(int pLen)
+	     {
+		 return 0;
+	     }
+
+	     public int GetOutputSize(int pLen)
+	     {
+		 if (forEncryption) {
+		     return (int)(pLen + thePlain.Length + BUFLEN);
+		 }
+		 int myCurr = (int)(pLen + theEncData.Length);
+		 return myCurr > BUFLEN ? myCurr - BUFLEN : 0;
+	     }
+
+	     public void Reset()
+	     {
+		 resetStreams();
+	     }
+
+	     /**
+	      * Reset Streams.
+	      */
+	     private void resetStreams()
+	     {
+		 /* Clear the plainText buffer */
+		 if (thePlain != null)
+		 {
+			 thePlain.Dispose();
+			 thePlain = new GCMSIVCache();  
+		 }
+
+		 /* Reset hashers */
+		 theAEADHasher.reset();
+		 theDataHasher.reset();
+
+		 /* Recreate streams (to release memory) */
+		 thePlain = new GCMSIVCache();
+		 theEncData = forEncryption ? null : new GCMSIVCache();
+
+		 /* Initialise AEAD if required */
+		 theFlags &= ~AEAD_COMPLETE;
+		 Arrays.Fill(theGHash, (byte) 0);
+		 if (theInitialAEAD != null)
+		 {
+		     theAEADHasher.updateHash(theInitialAEAD, 0, theInitialAEAD.Length);
+		 }
+	      }
+
+	     /**
+	      * Obtain buffer length (allowing for null).
+	      * @param pBuffer the buffere
+	      * @return the length
+	      */
+	     private static int bufLength(byte[] pBuffer)
+	     {
+		 return pBuffer == null ? 0 : pBuffer.Length;
+	     }
+
+	     /**
+	      * Check buffer.
+	      * @param pBuffer the buffer
+	      * @param pOffset the offset
+	      * @param pLen the length
+	      * @param pOutput is this an output buffer?
+	      */
+	     private static void checkBuffer(byte[] pBuffer,
+					     int pOffset,
+					     int pLen,
+					     bool pOutput)
+	     {
+		 /* Access lengths */
+		 int myBufLen = bufLength(pBuffer);
+		 int myLast = pOffset + pLen;
+
+		 /* Check for negative values and buffer overflow */
+		 bool badLen = pLen < 0 || pOffset < 0 || myLast < 0;
+		 if (badLen || myLast > myBufLen)
+		 {
+		     throw pOutput
+			     ? new OutputLengthException("Output buffer too short.")
+			     : new DataLengthException("Input buffer too short.");
+		 }
+	     }
+
+	     /**
+	      * encrypt data stream.
+	      * @param pCounter the counter
+	      * @param pTarget the target buffer
+	      * @param pOffset the target offset
+	      * @return the length of data encrypted
+	      */
+	     private int encryptPlain(byte[] pCounter,
+				      byte[] pTarget,
+				      int pOffset)
+	     {
+		 /* Access buffer and length */
+		 byte[] mySrc = thePlain.GetBuffer();
+		 byte[] myCounter = Arrays.Clone(pCounter);
+		 myCounter[BUFLEN - 1] |= MASK;
+		 byte[] myMask = new byte[BUFLEN];
+		 long myRemaining = thePlain.Length;
+		 int myOff = 0;
+
+		 /* While we have data to process */
+		 while (myRemaining > 0)
+		 {
+		     /* Generate the next mask */
+		     theCipher.ProcessBlock(myCounter, 0, myMask, 0);
+
+		     /* Xor data into mask */
+		     int myLen = (int)System.Math.Min(BUFLEN, myRemaining);
+		     xorBlock(myMask, mySrc, myOff, myLen);
+
+		     /* Copy encrypted data to output */
+		     Array.Copy(myMask, 0, pTarget, pOffset + myOff, myLen);
+
+		     /* Adjust counters */
+		     myRemaining -= myLen;
+		     myOff += myLen;
+		     incrementCounter(myCounter);
+		 }
+
+		 /* Return the amount of data processed */
+		 return (int)thePlain.Length;
+	     }
+
+	     /**
+	      * decrypt data stream.
+	      * @throws InvalidCipherTextException on data too short or mac check failed
+	      */
+	     private void decryptPlain()
+	     {
+		 /* Access buffer and length */
+		 byte[] mySrc = theEncData.GetBuffer();
+		 int myRemaining = (int)theEncData.Length - BUFLEN;
+
+		 /* Check for insufficient data */
+		 if (myRemaining < 0)
+		 {
+		     throw new InvalidCipherTextException("Data too short");
+		 }
+
+		 /* Access counter */
+		 byte[] myExpected = Arrays.CopyOfRange(mySrc, myRemaining, myRemaining + BUFLEN);
+		 byte[] myCounter = Arrays.Clone(myExpected);
+		 myCounter[BUFLEN - 1] |= MASK;
+		 byte[] myMask = new byte[BUFLEN];
+		 int myOff = 0;
+
+		 /* While we have data to process */
+		 while (myRemaining > 0)
+		 {
+		     /* Generate the next mask */
+		     theCipher.ProcessBlock(myCounter, 0, myMask, 0);
+
+		     /* Xor data into mask */
+		     int myLen = System.Math.Min(BUFLEN, myRemaining);
+		     xorBlock(myMask, mySrc, myOff, myLen);
+
+		     /* Write data to plain dataStream */
+		     thePlain.Write(myMask, 0, myLen);
+		     theDataHasher.updateHash(myMask, 0, myLen);
+
+		     /* Adjust counters */
+		     myRemaining -= myLen;
+		     myOff += myLen;
+		     incrementCounter(myCounter);
+		 }
+
+		 /* Derive and check the tag */
+		 byte[] myTag = calculateTag();
+		 if (!Arrays.ConstantTimeAreEqual(myTag, myExpected))
+		 {
+		     Reset();
+		     throw new InvalidCipherTextException("mac check failed");
+		 }
+	     }
+
+	     /**
+	      * calculate tag.
+	      * @return the calculated tag
+	      */
+	     private byte[] calculateTag()
+	     {
+		 /* Complete the hash */
+		 theDataHasher.completeHash();
+		 byte[] myPolyVal = completePolyVal();
+
+		 /* calculate polyVal */
+		 byte[] myResult = new byte[BUFLEN];
+
+		 /* Fold in the nonce */
+		 for (int i = 0; i < NONCELEN; i++)
+		 {
+		     myPolyVal[i] ^= theNonce[i];
+		 }
+
+		 /* Clear top bit */
+		 myPolyVal[BUFLEN - 1] &= (byte)(MASK - 1);
+
+		 /* Calculate tag and return it */
+		 theCipher.ProcessBlock(myPolyVal, 0, myResult, 0);
+		 return myResult;
+	     }
+
+	     /**
+	      * complete polyVAL.
+	      * @return the calculated value
+	      */
+	     private byte[] completePolyVal()
+	     {
+		 /* Build the polyVal result */
+		 byte[] myResult = new byte[BUFLEN];
+		 gHashLengths();
+		 fillReverse(theGHash, 0, BUFLEN, myResult);
+		 return myResult;
+	     }
+
+	     /**
+	      * process lengths.
+	      */
+	     private void gHashLengths()
+	     {
+		 /* Create reversed bigEndian buffer to keep it simple */
+		 byte[] myIn = new byte[BUFLEN];
+		 Pack.UInt64_To_BE((ulong)Bytes.SIZE * theDataHasher.getBytesProcessed(), myIn, 0);
+		 Pack.UInt64_To_BE((ulong)Bytes.SIZE * theAEADHasher.getBytesProcessed(), myIn, (int)Longs.BYTES);
+
+		 /* hash value */
+		 gHASH(myIn);
+	     }
+
+	     /**
+	      * perform the next GHASH step.
+	      * @param pNext the next value
+	      */
+	     private void gHASH(byte[] pNext)
+	     {
+		 	xorBlock(theGHash, pNext);
+		 	theMultiplier.MultiplyH(theGHash);
+	     }
+
+	     /**
+	      * Byte reverse a buffer.
+	      * @param pInput the input buffer
+	      * @param pOffset the offset
+	      * @param pLength the length of data (<= BUFLEN)
+	      * @param pOutput the output buffer
+	      */
+	     private static void fillReverse(byte[] pInput,
+					     int pOffset,
+					     int pLength,
+					     byte[] pOutput)
+	     {
+		 /* Loop through the buffer */
+		 for (int i = 0, j = BUFLEN - 1; i < pLength; i++, j--)
+		 {
+		     /* Copy byte */
+		     pOutput[j] = pInput[pOffset + i];
+		 }
+	     }
+
+	     /**
+	      * xor a full block buffer.
+	      * @param pLeft the left operand and result
+	      * @param pRight the right operand
+	      */
+	     private static void xorBlock(byte[] pLeft,
+					  byte[] pRight)
+	     {
+		 /* Loop through the bytes */
+		 for (int i = 0; i < BUFLEN; i++)
+		 {
+		     pLeft[i] ^= pRight[i];
+		 }
+	     }
+
+	     /**
+	      * xor a partial block buffer.
+	      * @param pLeft the left operand and result
+	      * @param pRight the right operand
+	      * @param pOffset the offset in the right operand
+	      * @param pLength the length of data in the right operand
+	      */
+	     private static void xorBlock(byte[] pLeft,
+					  byte[] pRight,
+					  int pOffset,
+					  int pLength)
+					  {
+		 /* Loop through the bytes */
+		 for (int i = 0; i < pLength; i++)
+		 {
+		     pLeft[i] ^= pRight[i + pOffset];
+		 }
+	     }
+
+	     /**
+	      * increment the counter.
+	      * @param pCounter the counter to increment
+	      */
+	     private static void incrementCounter(byte[] pCounter)
+	     {
+		 /* Loop through the bytes incrementing counter */
+		 for (int i = 0; i < Integers.BYTES; i++)
+		 {
+		     if (++pCounter[i] != 0)
+		     {
+			 break;
+		     }
+		 }
+	     }
+
+	     /**
+	      * multiply by X.
+	      * @param pValue the value to adjust
+	      */
+	     private static void mulX(byte[] pValue)
+	     {
+		 /* Loop through the bytes */
+		 byte myMask = (byte) 0;
+		 for (int i = 0; i < BUFLEN; i++)
+		 {
+		     byte myValue = pValue[i];
+		     pValue[i] = (byte) (((myValue >> 1) & ~MASK) | myMask);
+		     myMask = (byte)((myValue & 1) == 0 ? 0 : MASK);
+		 }
+
+		 /* Xor in addition if last bit was set */
+		 if (myMask != 0)
+		 {
+		     pValue[0] ^= ADD;
+		 }
+	     }
+
+	     /**
+	      * Derive Keys.
+	      * @param pKey the keyGeneration key
+	      */
+	     private void deriveKeys(KeyParameter pKey)
+	     {
+		 /* Create the buffers */
+		 byte[] myIn = new byte[BUFLEN];
+		 byte[] myOut = new byte[BUFLEN];
+		 byte[] myResult = new byte[BUFLEN];
+		 byte[] myEncKey = new byte[pKey.GetKey().Length];
+
+		 /* Prepare for encryption */
+		 Array.Copy(theNonce, 0, myIn, BUFLEN - NONCELEN, NONCELEN);
+		 theCipher.Init(true, pKey);
+
+		 /* Derive authentication key */
+		 int myOff = 0;
+		 theCipher.ProcessBlock(myIn, 0, myOut, 0);
+		 Array.Copy(myOut, 0, myResult, myOff, HALFBUFLEN);
+		 myIn[0]++;
+		 myOff += HALFBUFLEN;
+		 theCipher.ProcessBlock(myIn, 0, myOut, 0);
+		 Array.Copy(myOut, 0, myResult, myOff, HALFBUFLEN);
+
+		 /* Derive encryption key */
+		 myIn[0]++;
+		 myOff = 0;
+		 theCipher.ProcessBlock(myIn, 0, myOut, 0);
+		 Array.Copy(myOut, 0, myEncKey, myOff, HALFBUFLEN);
+		 myIn[0]++;
+		 myOff += HALFBUFLEN;
+		 theCipher.ProcessBlock(myIn, 0, myOut, 0);
+		 Array.Copy(myOut, 0, myEncKey, myOff, HALFBUFLEN);
+
+		 /* If we have a 32byte key */
+		 if (myEncKey.Length == BUFLEN << 1)
+		 {
+		     /* Derive remainder of encryption key */
+		     myIn[0]++;
+		     myOff += HALFBUFLEN;
+		     theCipher.ProcessBlock(myIn, 0, myOut, 0);
+		     Array.Copy(myOut, 0, myEncKey, myOff, HALFBUFLEN);
+		     myIn[0]++;
+		     myOff += HALFBUFLEN;
+		     theCipher.ProcessBlock(myIn, 0, myOut, 0);
+		     Array.Copy(myOut, 0, myEncKey, myOff, HALFBUFLEN);
+		 }
+
+		 /* Initialise the Cipher */
+		 theCipher.Init(true, new KeyParameter(myEncKey));
+
+		 /* Initialise the multiplier */
+		 fillReverse(myResult, 0, BUFLEN, myOut);
+		 mulX(myOut);
+		 theMultiplier.Init(myOut);
+		 theFlags |= INIT;
+	     }
+
+	     /**
+	      * GCMSIVCache.
+	      */
+	     class GCMSIVCache
+		     : MemoryOutputStream
+	     {
+		 /**
+		  * number of bytes hashed.
+		  */
+		 private int numHashed;
+
+		 /**
+		  * Constructor.
+		  */
+		 internal GCMSIVCache()
+		 {
+		 }
+	     }
+
+	     /**
+	      * Hash Control.
+	      */
+	     class GCMSIVHasher
+	     {
+		 /**
+		  * Cache.
+		  */
+		 private readonly byte[] theBuffer = new byte[BUFLEN];
+
+		 /**
+		  * Single byte cache.
+		  */
+		 private readonly byte[] theByte = new byte[1];
+
+		 /**
+		  * Count of active bytes in cache.
+		  */
+		 private int numActive;
+
+		 /**
+		  * Count of hashed bytes.
+		  */
+		 private ulong numHashed;
+
+		private readonly GcmSivBlockCipher parent;
+
+		internal GCMSIVHasher(GcmSivBlockCipher parent)
+		{
+			this.parent = parent;
+		}
+
+		 /**
+		  * Obtain the count of bytes hashed.
+		  * @return the count
+		  */
+		 internal ulong getBytesProcessed()
+		 {
+		     return numHashed;
+		 }
+
+		 /**
+		  * Reset the hasher.
+		  */
+		 internal void reset()
+		 {
+		     numActive = 0;
+		     numHashed = 0;
+		 }
+
+		 /**
+		  * update hash.
+		  * @param pByte the byte
+		  */
+		 internal void updateHash(byte pByte)
+		 {
+		     theByte[0] = pByte;
+		     updateHash(theByte, 0, 1);
+		 }
+
+		 /**
+		  * update hash.
+		  * @param pBuffer the buffer
+		  * @param pOffset the offset within the buffer
+		  * @param pLen the length of data
+		  */
+		 internal void updateHash(byte[] pBuffer,
+				 int pOffset,
+				 int pLen)
+		 {
+		     /* If we should process the cache */
+		     int mySpace = BUFLEN - numActive;
+		     int numProcessed = 0;
+		     int myRemaining = pLen;
+		     if (numActive > 0
+			     && pLen >= mySpace)
+		     {
+			 /* Copy data into the cache and hash it */
+			 Array.Copy(pBuffer, pOffset, theBuffer, numActive, mySpace);
+			 fillReverse(theBuffer, 0, BUFLEN, parent.theReverse);
+			 parent.gHASH(parent.theReverse);
+
+			 /* Adjust counters */
+			 numProcessed += mySpace;
+			 myRemaining -= mySpace;
+			 numActive = 0;
+		     }
+
+		     /* While we have full blocks */
+		     while (myRemaining >= BUFLEN)
+		     {
+			 /* Access the next data */
+			 fillReverse(pBuffer, pOffset + numProcessed, BUFLEN, parent.theReverse);
+			 parent.gHASH(parent.theReverse);
+
+			 /* Adjust counters */
+			 numProcessed += mySpace;
+			 myRemaining -= mySpace;
+		     }
+
+		     /* If we have remaining data */
+		     if (myRemaining > 0)
+		     {
+			 /* Copy data into the cache */
+			 Array.Copy(pBuffer, pOffset + numProcessed, theBuffer, numActive, myRemaining);
+			 numActive += myRemaining;
+		     }
+
+		     /* Adjust the number of bytes processed */
+		     numHashed += (ulong)pLen;
+		 }
+
+		 /**
+		  * complete hash.
+		  */
+		 internal void completeHash()
+		 {
+		     /* If we have remaining data */
+		     if (numActive > 0)
+		     {
+			 /* Access the next data */
+			 Arrays.Fill(parent.theReverse, (byte) 0);
+			 fillReverse(theBuffer, 0, numActive, parent.theReverse);
+
+			 /* hash value */
+			 parent.gHASH(parent.theReverse);
+		     }
+		 }
+	     }
+	 }
+}
diff --git a/crypto/src/crypto/parameters/FpeParameters.cs b/crypto/src/crypto/parameters/FpeParameters.cs
new file mode 100644
index 000000000..ab8833312
--- /dev/null
+++ b/crypto/src/crypto/parameters/FpeParameters.cs
@@ -0,0 +1,49 @@
+using System;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Parameters
+{
+public sealed class FpeParameters
+    : ICipherParameters
+{
+    private readonly KeyParameter key;
+    private readonly int radix;
+    private readonly byte[] tweak;
+    private readonly bool useInverse;
+
+    public FpeParameters(KeyParameter key, int radix, byte[] tweak): this(key, radix, tweak, false)
+    {
+        
+    }
+
+    public FpeParameters(KeyParameter key, int radix, byte[] tweak, bool useInverse)
+    {
+        this.key = key;
+        this.radix = radix;
+        this.tweak = Arrays.Clone(tweak);
+        this.useInverse = useInverse;
+    }
+
+    public KeyParameter Key
+    {
+        get { return key; }
+    }
+
+    public int Radix
+    {
+        get { return radix; }
+    }
+
+    public bool UseInverseFunction
+    {
+        get { return useInverse; }
+    }
+
+    public byte[] GetTweak()
+    {
+        return Arrays.Clone(tweak);
+    }
+}
+}
diff --git a/crypto/src/crypto/util/BasicAlphabetMapper.cs b/crypto/src/crypto/util/BasicAlphabetMapper.cs
new file mode 100644
index 000000000..bd0411e30
--- /dev/null
+++ b/crypto/src/crypto/util/BasicAlphabetMapper.cs
@@ -0,0 +1,104 @@
+using System;
+using System.Collections;
+
+namespace Org.BouncyCastle.Crypto.Utilities
+{
+/**
+ * A basic alphabet mapper that just creates a mapper based on the
+ * passed in array of characters.
+ */
+ public class BasicAlphabetMapper
+    : IAlphabetMapper
+{
+    private Hashtable indexMap = new Hashtable();
+    private Hashtable charMap = new Hashtable();
+
+    /**
+     * Base constructor.
+     *
+     * @param alphabet a string of characters making up the alphabet.
+     */    
+    public BasicAlphabetMapper(string alphabet) :
+        this(alphabet.ToCharArray())
+    {
+    }
+
+    /**
+     * Base constructor.
+     *
+     * @param alphabet an array of characters making up the alphabet.
+     */
+    public BasicAlphabetMapper(char[] alphabet)
+    {
+        for (int i = 0; i != alphabet.Length; i++)
+        {
+            if (indexMap.ContainsKey(alphabet[i]))
+            {
+                throw new ArgumentException("duplicate key detected in alphabet: " + alphabet[i]);
+            }
+            indexMap.Add(alphabet[i], i);
+            charMap.Add(i, alphabet[i]);
+        }
+    }
+
+    public int Radix
+    {
+        get { return indexMap.Count; }
+    }
+
+    public byte[] ConvertToIndexes(char[] input)
+    {
+        byte[] outBuf;
+
+        if (indexMap.Count <= 256)
+        {
+            outBuf = new byte[input.Length];
+            for (int i = 0; i != input.Length; i++)
+            {
+                outBuf[i] = (byte)indexMap[input[i]];
+            }
+        }
+        else
+        {
+            outBuf = new byte[input.Length * 2];
+            for (int i = 0; i != input.Length; i++)
+            {
+                int idx = (int)indexMap[input[i]];
+                outBuf[i * 2] = (byte)((idx >> 8) & 0xff);
+                outBuf[i * 2  + 1] = (byte)(idx & 0xff);
+            }
+        }
+
+        return outBuf;
+    }
+
+    public char[] ConvertToChars(byte[] input)
+    {
+        char[] outBuf;
+
+        if (charMap.Count <= 256)
+        {
+            outBuf = new char[input.Length];
+            for (int i = 0; i != input.Length; i++)
+            {
+                outBuf[i] = (char)charMap[input[i] & 0xff];
+            }
+        }
+        else
+        {
+            if ((input.Length & 0x1) != 0)
+            {
+                throw new ArgumentException("two byte radix and input string odd.Length");
+            }
+            
+            outBuf = new char[input.Length / 2];
+            for (int i = 0; i != input.Length; i += 2)
+            {
+                outBuf[i / 2] = (char)charMap[((input[i] << 8) & 0xff00) | (input[i + 1] & 0xff)];
+            }
+        }
+
+        return outBuf;
+    }
+}
+}
diff --git a/crypto/src/util/Arrays.cs b/crypto/src/util/Arrays.cs
index 784d45efb..78c4e8ffc 100644
--- a/crypto/src/util/Arrays.cs
+++ b/crypto/src/util/Arrays.cs
@@ -467,6 +467,17 @@ namespace Org.BouncyCastle.Utilities
             return data == null ? null : (byte[])data.Clone();
         }
 
+        public static short[] Clone(short[] data)
+        {
+            return data == null ? null : (short[])data.Clone();
+        }
+
+        [CLSCompliantAttribute(false)]
+        public static ushort[] Clone(ushort[] data)
+        {
+            return data == null ? null : (ushort[])data.Clone();
+        }
+
         public static int[] Clone(int[] data)
         {
             return data == null ? null : (int[])data.Clone();
@@ -694,6 +705,19 @@ namespace Org.BouncyCastle.Utilities
             return rv;
         }
 
+        public static ushort[] Concatenate(ushort[] a, ushort[] b)
+        {
+            if (a == null)
+                return Clone(b);
+            if (b == null)
+                return Clone(a);
+
+            ushort[] rv = new ushort[a.Length + b.Length];
+            Array.Copy(a, 0, rv, 0, a.Length);
+            Array.Copy(b, 0, rv, a.Length, b.Length);
+            return rv;
+        }
+
         public static byte[] ConcatenateAll(params byte[][] vs)
         {
             byte[][] nonNull = new byte[vs.Length][];
diff --git a/crypto/src/util/Bytes.cs b/crypto/src/util/Bytes.cs
new file mode 100644
index 000000000..0d73d67ae
--- /dev/null
+++ b/crypto/src/util/Bytes.cs
@@ -0,0 +1,10 @@
+using System;
+
+namespace Org.BouncyCastle.Utilities
+{
+    public abstract class Bytes
+    {
+        public static readonly uint BYTES = 1;
+        public static readonly uint SIZE = 8;
+    }
+}
diff --git a/crypto/src/util/Integers.cs b/crypto/src/util/Integers.cs
index b243b88b2..b7bd25ce6 100644
--- a/crypto/src/util/Integers.cs
+++ b/crypto/src/util/Integers.cs
@@ -6,6 +6,9 @@ namespace Org.BouncyCastle.Utilities
 {
     public abstract class Integers
     {
+        public static readonly uint BYTES = 4;
+        public static readonly uint SIZE = 32;
+
         private static readonly byte[] DeBruijnTZ = {
             0x00, 0x01, 0x02, 0x18, 0x03, 0x13, 0x06, 0x19, 0x16, 0x04, 0x14, 0x0A,
             0x10, 0x07, 0x0C, 0x1A, 0x1F, 0x17, 0x12, 0x05, 0x15, 0x09, 0x0F, 0x0B,
diff --git a/crypto/src/util/Longs.cs b/crypto/src/util/Longs.cs
index d206c1f81..892e57137 100644
--- a/crypto/src/util/Longs.cs
+++ b/crypto/src/util/Longs.cs
@@ -6,6 +6,9 @@ namespace Org.BouncyCastle.Utilities
 {
     public abstract class Longs
     {
+        public static readonly uint BYTES = 8;
+        public static readonly uint SIZE = 64;
+
         public static long Reverse(long i)
         {
             i = (long)Bits.BitPermuteStepSimple((ulong)i, 0x5555555555555555UL, 1);