1 files changed, 102 insertions, 0 deletions
diff --git a/crypto/src/asn1/nist/KMACwithSHAKE256_params.cs b/crypto/src/asn1/nist/KMACwithSHAKE256_params.cs
new file mode 100644
index 000000000..fa7471913
--- /dev/null
+++ b/crypto/src/asn1/nist/KMACwithSHAKE256_params.cs
@@ -0,0 +1,102 @@
+using Org.BouncyCastle.Utilities;
+using System;
+
+namespace Org.BouncyCastle.Asn1.Nist
+{
+    /// <summary>
+    /// KMACwithSHAKE256-params ::= SEQUENCE {
+    ///     kMACOutputLength     INTEGER DEFAULT 512, -- Output length in bits
+    ///     customizationString  OCTET STRING DEFAULT ''H
+    /// } 
+    /// </summary>
+public class KMacWithShake256Params : Asn1Encodable
+{
+    private static readonly byte[] EMPTY_STRING = new byte[0];
+    private static readonly int DEF_LENGTH = 512;
+
+    private readonly int outputLength;
+    private readonly byte[] customizationString;
+
+    public KMacWithShake256Params(int outputLength)
+    {
+        this.outputLength = outputLength;
+        this.customizationString = EMPTY_STRING;
+    }
+
+    public KMacWithShake256Params(int outputLength, byte[] customizationString)
+    {
+        this.outputLength = outputLength;
+        this.customizationString = Arrays.Clone(customizationString);
+    }
+
+    public static KMacWithShake256Params GetInstance(Object o)
+    {
+        if (o is KMacWithShake256Params)
+        {
+            return (KMacWithShake256Params)o;
+        }
+        else if (o != null)
+        {
+            return new KMacWithShake256Params(Asn1Sequence.GetInstance(o));
+        }
+
+        return null;
+    }
+
+    private KMacWithShake256Params(Asn1Sequence seq)
+    {
+        if (seq.Count > 2)
+            throw new InvalidOperationException("sequence size greater than 2");
+
+        if (seq.Count == 2)
+        {
+            this.outputLength = DerInteger.GetInstance(seq[0]).IntValueExact;
+            this.customizationString = Arrays.Clone(Asn1OctetString.GetInstance(seq[1]).GetOctets());
+        }
+        else if (seq.Count == 1)
+        {
+            if (seq[0] is DerInteger)
+            {
+                this.outputLength = DerInteger.GetInstance(seq[0]).IntValueExact;
+                this.customizationString = EMPTY_STRING;
+            }
+            else
+            {
+                this.outputLength = DEF_LENGTH;
+                this.customizationString = Arrays.Clone(Asn1OctetString.GetInstance(seq[0]).GetOctets());
+            }
+        }
+        else
+        {
+            this.outputLength = DEF_LENGTH;
+            this.customizationString = EMPTY_STRING;
+        }
+    }
+
+    public int OutputLength
+    {
+        get { return outputLength; }
+    }
+
+    public byte[] CustomizationString
+    {
+        get { return Arrays.Clone(customizationString); }
+    }
+
+    public override Asn1Object ToAsn1Object()
+    {
+        Asn1EncodableVector v = new Asn1EncodableVector();
+        if (outputLength != DEF_LENGTH)
+        {
+            v.Add(new DerInteger(outputLength));
+        }
+
+        if (customizationString.Length != 0)
+        {
+            v.Add(new DerOctetString(CustomizationString));
+        }
+
+        return new DerSequence(v);
+    }
+}
+}