Initial implementation of Threefish + Skein

core/src/main/java/org/bouncycastle/crypto/digests/SkeinDigest.java

@@ -0,0 +1,112 @@
+package org.bouncycastle.crypto.digests;
+
+import org.bouncycastle.crypto.ExtendedDigest;
+import org.bouncycastle.crypto.engines.ThreefishEngine;
+import org.bouncycastle.crypto.params.SkeinParameters;
+import org.bouncycastle.util.Memoable;
+
+/**
+ * Implementation of the Skein parameterised hash 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 SkeinDigest implements ExtendedDigest, Memoable
+{
+    /** 256 bit block size - Skein-256 */
+    public static final int SKEIN_256 = SkeinEngine.SKEIN_256;
+    /** 512 bit block size - Skein-512 */
+    public static final int SKEIN_512 = SkeinEngine.SKEIN_512;
+    /** 1024 bit block size - Skein-1024 */
+    public static final int SKEIN_1024 = SkeinEngine.SKEIN_1024;
+
+    private SkeinEngine engine;
+
+    /**
+     * Constructs a Skein digest 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/digest size to produce in bits, which must be an integral number of
+     *            bytes.
+     */
+    public SkeinDigest(int stateSizeBits, int digestSizeBits)
+    {
+        this.engine = new SkeinEngine(stateSizeBits, digestSizeBits);
+        init(null);
+    }
+
+    public SkeinDigest(SkeinDigest digest)
+    {
+        this.engine = new SkeinEngine(digest.engine);
+    }
+
+    public void reset(Memoable other)
+    {
+        SkeinDigest d = (SkeinDigest)other;
+        engine.reset(d.engine);
+    }
+
+    public Memoable copy()
+    {
+        return new SkeinDigest(this);
+    }
+
+    public String getAlgorithmName()
+    {
+        return "Skein-" + (engine.getBlockSize() * 8) + "-" + (engine.getOutputSize() * 8);
+    }
+
+    public int getDigestSize()
+    {
+        return engine.getOutputSize();
+    }
+
+    public int getByteLength()
+    {
+        return engine.getBlockSize();
+    }
+
+    /**
+     * Optionally initialises the Skein digest with the provided parameters.<br>
+     * See {@link SkeinParameters} for details on the parameterisation of the Skein hash function.
+     * 
+     * @param params
+     *            the parameters to apply to this engine, or <code>null</code> to use no parameters.
+     */
+    public void init(SkeinParameters params)
+    {
+        engine.init(params);
+    }
+
+    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);
+    }
+
+}