1 files changed, 119 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/macs/SkeinMac.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/macs/SkeinMac.java
new file mode 100644
index 000000000..4d2ec47fe
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/macs/SkeinMac.java
@@ -0,0 +1,119 @@
+package org.spongycastle.crypto.macs;
+
+import org.spongycastle.crypto.CipherParameters;
+import org.spongycastle.crypto.Mac;
+import org.spongycastle.crypto.digests.SkeinEngine;
+import org.spongycastle.crypto.engines.ThreefishEngine;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.crypto.params.SkeinParameters;
+
+/**
+ * Implementation of the Skein parameterised MAC function in 256, 512 and 1024 bit block sizes,
+ * based on the {@link ThreefishEngine Threefish} tweakable block cipher.
+ * <p/>
+ * This is the 1.3 version of Skein defined in the Skein hash function submission to the NIST SHA-3
+ * competition in October 2010.
+ * <p/>
+ * Skein was designed by Niels Ferguson - Stefan Lucks - Bruce Schneier - Doug Whiting - Mihir
+ * Bellare - Tadayoshi Kohno - Jon Callas - Jesse Walker.
+ * <p/>
+ *
+ * @see SkeinEngine
+ * @see SkeinParameters
+ */
+public class SkeinMac
+    implements Mac
+{
+    /**
+     * 256 bit block size - Skein MAC-256
+     */
+    public static final int SKEIN_256 = SkeinEngine.SKEIN_256;
+    /**
+     * 512 bit block size - Skein MAC-512
+     */
+    public static final int SKEIN_512 = SkeinEngine.SKEIN_512;
+    /**
+     * 1024 bit block size - Skein MAC-1024
+     */
+    public static final int SKEIN_1024 = SkeinEngine.SKEIN_1024;
+
+    private SkeinEngine engine;
+
+    /**
+     * Constructs a Skein MAC with an internal state size and output size.
+     *
+     * @param stateSizeBits  the internal state size in bits - one of {@link #SKEIN_256}, {@link #SKEIN_512} or
+     *                       {@link #SKEIN_1024}.
+     * @param digestSizeBits the output/MAC size to produce in bits, which must be an integral number of bytes.
+     */
+    public SkeinMac(int stateSizeBits, int digestSizeBits)
+    {
+        this.engine = new SkeinEngine(stateSizeBits, digestSizeBits);
+    }
+
+    public SkeinMac(SkeinMac mac)
+    {
+        this.engine = new SkeinEngine(mac.engine);
+    }
+
+    public String getAlgorithmName()
+    {
+        return "Skein-MAC-" + (engine.getBlockSize() * 8) + "-" + (engine.getOutputSize() * 8);
+    }
+
+    /**
+     * Initialises the Skein digest with the provided parameters.<br>
+     * See {@link SkeinParameters} for details on the parameterisation of the Skein hash function.
+     *
+     * @param params an instance of {@link SkeinParameters} or {@link KeyParameter}.
+     */
+    public void init(CipherParameters params)
+        throws IllegalArgumentException
+    {
+        SkeinParameters skeinParameters;
+        if (params instanceof SkeinParameters)
+        {
+            skeinParameters = (SkeinParameters)params;
+        }
+        else if (params instanceof KeyParameter)
+        {
+            skeinParameters = new SkeinParameters.Builder().setKey(((KeyParameter)params).getKey()).build();
+        }
+        else
+        {
+            throw new IllegalArgumentException("Invalid parameter passed to Skein MAC init - "
+                + params.getClass().getName());
+        }
+        if (skeinParameters.getKey() == null)
+        {
+            throw new IllegalArgumentException("Skein MAC requires a key parameter.");
+        }
+        engine.init(skeinParameters);
+    }
+
+    public int getMacSize()
+    {
+        return engine.getOutputSize();
+    }
+
+    public void reset()
+    {
+        engine.reset();
+    }
+
+    public void update(byte in)
+    {
+        engine.update(in);
+    }
+
+    public void update(byte[] in, int inOff, int len)
+    {
+        engine.update(in, inOff, len);
+    }
+
+    public int doFinal(byte[] out, int outOff)
+    {
+        return engine.doFinal(out, outOff);
+    }
+
+}