diff --git a/crypto/src/crypto/modes/SicBlockCipher.cs b/crypto/src/crypto/modes/SicBlockCipher.cs
new file mode 100644
index 000000000..07c5d1978
--- /dev/null
+++ b/crypto/src/crypto/modes/SicBlockCipher.cs
@@ -0,0 +1,115 @@
+using System;
+
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Math;
+
+namespace Org.BouncyCastle.Crypto.Modes
+{
+ /**
+ * Implements the Segmented Integer Counter (SIC) mode on top of a simple
+ * block cipher.
+ */
+ public class SicBlockCipher
+ : IBlockCipher
+ {
+ private readonly IBlockCipher cipher;
+ private readonly int blockSize;
+ private readonly byte[] IV;
+ private readonly byte[] counter;
+ private readonly byte[] counterOut;
+
+ /**
+ * Basic constructor.
+ *
+ * @param c the block cipher to be used.
+ */
+ public SicBlockCipher(IBlockCipher cipher)
+ {
+ this.cipher = cipher;
+ this.blockSize = cipher.GetBlockSize();
+ this.IV = new byte[blockSize];
+ this.counter = new byte[blockSize];
+ this.counterOut = new byte[blockSize];
+ }
+
+ /**
+ * return the underlying block cipher that we are wrapping.
+ *
+ * @return the underlying block cipher that we are wrapping.
+ */
+ public IBlockCipher GetUnderlyingCipher()
+ {
+ return cipher;
+ }
+
+ public void Init(
+ bool forEncryption, //ignored by this CTR mode
+ ICipherParameters parameters)
+ {
+ if (parameters is ParametersWithIV)
+ {
+ ParametersWithIV ivParam = (ParametersWithIV) parameters;
+ byte[] iv = ivParam.GetIV();
+ Array.Copy(iv, 0, IV, 0, IV.Length);
+
+ Reset();
+
+ // if null it's an IV changed only.
+ if (ivParam.Parameters != null)
+ {
+ cipher.Init(true, ivParam.Parameters);
+ }
+ }
+ else
+ {
+ throw new ArgumentException("SIC mode requires ParametersWithIV", "parameters");
+ }
+ }
+
+ public string AlgorithmName
+ {
+ get { return cipher.AlgorithmName + "/SIC"; }
+ }
+
+ public bool IsPartialBlockOkay
+ {
+ get { return true; }
+ }
+
+ public int GetBlockSize()
+ {
+ return cipher.GetBlockSize();
+ }
+
+ public int ProcessBlock(
+ byte[] input,
+ int inOff,
+ byte[] output,
+ int outOff)
+ {
+ cipher.ProcessBlock(counter, 0, counterOut, 0);
+
+ //
+ // XOR the counterOut with the plaintext producing the cipher text
+ //
+ for (int i = 0; i < counterOut.Length; i++)
+ {
+ output[outOff + i] = (byte)(counterOut[i] ^ input[inOff + i]);
+ }
+
+ // Increment the counter
+ int j = counter.Length;
+ while (--j >= 0 && ++counter[j] == 0)
+ {
+ }
+
+ return counter.Length;
+ }
+
+ public void Reset()
+ {
+ Array.Copy(IV, 0, counter, 0, counter.Length);
+ cipher.Reset();
+ }
+ }
+}
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