Extend EncodableDigest implementation to all SHA-2 digests.

4 files changed, 103 insertions, 9 deletions

diff --git a/core/src/main/java/org/bouncycastle/crypto/digests/LongDigest.java b/core/src/main/java/org/bouncycastle/crypto/digests/LongDigest.java
index 12836389..8ea474b3 100644
--- a/core/src/main/java/org/bouncycastle/crypto/digests/LongDigest.java
+++ b/core/src/main/java/org/bouncycastle/crypto/digests/LongDigest.java
@@ -8,11 +8,11 @@ import org.bouncycastle.util.Pack;
  * Base class for SHA-384 and SHA-512.
  */
 public abstract class LongDigest
-    implements ExtendedDigest, Memoable
+    implements ExtendedDigest, Memoable, EncodableDigest
 {
     private static final int BYTE_LENGTH = 128;
-    
-    private byte[]  xBuf;
+
+    private byte[] xBuf = new byte[8];
     private int     xBufOff;
 
     private long    byteCount1;
@@ -28,7 +28,6 @@ public abstract class LongDigest
      */
     protected LongDigest()
     {
-        xBuf = new byte[8];
         xBufOff = 0;
 
         reset();
@@ -41,8 +40,6 @@ public abstract class LongDigest
      */
     protected LongDigest(LongDigest t)
     {
-        xBuf = new byte[t.xBuf.length];
-
         copyIn(t);
     }
 
@@ -67,6 +64,56 @@ public abstract class LongDigest
         wOff = t.wOff;
     }
 
+    protected void populateState(byte[] state)
+    {
+        System.arraycopy(xBuf, 0, state, 0, xBufOff);
+        Pack.intToBigEndian(xBufOff, state, 8);
+        Pack.longToBigEndian(byteCount1, state, 12);
+        Pack.longToBigEndian(byteCount2, state, 20);
+        Pack.longToBigEndian(H1, state, 28);
+        Pack.longToBigEndian(H2, state, 36);
+        Pack.longToBigEndian(H3, state, 44);
+        Pack.longToBigEndian(H4, state, 52);
+        Pack.longToBigEndian(H5, state, 60);
+        Pack.longToBigEndian(H6, state, 68);
+        Pack.longToBigEndian(H7, state, 76);
+        Pack.longToBigEndian(H8, state, 84);
+
+        Pack.intToBigEndian(wOff, state, 92);
+        for (int i = 0; i < wOff; i++)
+        {
+            Pack.longToBigEndian(W[i], state, 96 + (i * 8));
+        }
+    }
+
+    protected void restoreState(byte[] encodedState)
+    {
+        xBufOff = Pack.bigEndianToInt(encodedState, 8);
+        System.arraycopy(encodedState, 0, xBuf, 0, xBufOff);
+        byteCount1 = Pack.bigEndianToLong(encodedState, 12);
+        byteCount2 = Pack.bigEndianToLong(encodedState, 20);
+
+        H1 = Pack.bigEndianToLong(encodedState, 28);
+        H2 = Pack.bigEndianToLong(encodedState, 36);
+        H3 = Pack.bigEndianToLong(encodedState, 44);
+        H4 = Pack.bigEndianToLong(encodedState, 52);
+        H5 = Pack.bigEndianToLong(encodedState, 60);
+        H6 = Pack.bigEndianToLong(encodedState, 68);
+        H7 = Pack.bigEndianToLong(encodedState, 76);
+        H8 = Pack.bigEndianToLong(encodedState, 84);
+
+        wOff = Pack.bigEndianToInt(encodedState, 92);
+        for (int i = 0; i < wOff; i++)
+        {
+            W[i] = Pack.bigEndianToLong(encodedState, 96 + (i * 8));
+        }
+    }
+
+    protected int getEncodedStateSize()
+    {
+        return 96 + (wOff * 8);
+    }
+
     public void update(
         byte in)
     {
@@ -165,7 +212,7 @@ public abstract class LongDigest
     {
         return BYTE_LENGTH;
     }
-    
+
     protected void processWord(
         byte[]  in,
         int     inOff)
@@ -228,7 +275,7 @@ public abstract class LongDigest
         long     g = H7;
         long     h = H8;
 
-        int t = 0;     
+        int t = 0;
         for(int i = 0; i < 10; i ++)
         {
           // t = 8 * i
@@ -271,7 +318,7 @@ public abstract class LongDigest
           e += a;
           a += Sum0(b) + Maj(b, c, d);
         }
- 
+
         H1 += a;
         H2 += b;
         H3 += c;
@@ -358,4 +405,5 @@ public abstract class LongDigest
 0x28db77f523047d84L, 0x32caab7b40c72493L, 0x3c9ebe0a15c9bebcL, 0x431d67c49c100d4cL,
 0x4cc5d4becb3e42b6L, 0x597f299cfc657e2aL, 0x5fcb6fab3ad6faecL, 0x6c44198c4a475817L
     };
+
 }
diff --git a/core/src/main/java/org/bouncycastle/crypto/digests/SHA384Digest.java b/core/src/main/java/org/bouncycastle/crypto/digests/SHA384Digest.java
index c80aaefb..fc9fa1e7 100644
--- a/core/src/main/java/org/bouncycastle/crypto/digests/SHA384Digest.java
+++ b/core/src/main/java/org/bouncycastle/crypto/digests/SHA384Digest.java
@@ -36,6 +36,11 @@ public class SHA384Digest
         super(t);
     }
 
+    public SHA384Digest(byte[] encodedState)
+    {
+        restoreState(encodedState);
+    }
+
     public String getAlgorithmName()
     {
         return "SHA-384";
@@ -96,4 +101,11 @@ public class SHA384Digest
 
         super.copyIn(d);
     }
+
+    public byte[] getEncodedState()
+    {
+        byte[] encoded = new byte[getEncodedStateSize()];
+        super.populateState(encoded);
+        return encoded;
+    }
 }
diff --git a/core/src/main/java/org/bouncycastle/crypto/digests/SHA512Digest.java b/core/src/main/java/org/bouncycastle/crypto/digests/SHA512Digest.java
index c4b59d70..644bafad 100644
--- a/core/src/main/java/org/bouncycastle/crypto/digests/SHA512Digest.java
+++ b/core/src/main/java/org/bouncycastle/crypto/digests/SHA512Digest.java
@@ -36,6 +36,11 @@ public class SHA512Digest
         super(t);
     }
 
+    public SHA512Digest(byte[] encodedState)
+    {
+        restoreState(encodedState);
+    }
+
     public String getAlgorithmName()
     {
         return "SHA-512";
@@ -98,5 +103,12 @@ public class SHA512Digest
 
         copyIn(d);
     }
+
+    public byte[] getEncodedState()
+    {
+        byte[] encoded = new byte[getEncodedStateSize()];
+        super.populateState(encoded);
+        return encoded;
+    }
 }
 
diff --git a/core/src/main/java/org/bouncycastle/crypto/digests/SHA512tDigest.java b/core/src/main/java/org/bouncycastle/crypto/digests/SHA512tDigest.java
index 46154618..9abf73b4 100644
--- a/core/src/main/java/org/bouncycastle/crypto/digests/SHA512tDigest.java
+++ b/core/src/main/java/org/bouncycastle/crypto/digests/SHA512tDigest.java
@@ -2,6 +2,7 @@ package org.bouncycastle.crypto.digests;
 
 import org.bouncycastle.util.Memoable;
 import org.bouncycastle.util.MemoableResetException;
+import org.bouncycastle.util.Pack;
 
 /**
  * FIPS 180-4 implementation of SHA-512/t
@@ -53,6 +54,17 @@ public class SHA512tDigest
         reset(t);
     }
 
+    public SHA512tDigest(byte[] encodedState)
+    {
+        this(readDigestLength(encodedState));
+        restoreState(encodedState);
+    }
+
+    private static int readDigestLength(byte[] encodedState)
+    {
+        return Pack.bigEndianToInt(encodedState, encodedState.length - 4);
+    }
+
     public String getAlgorithmName()
     {
         return "SHA-512/" + Integer.toString(digestLength * 8);
@@ -202,4 +214,14 @@ public class SHA512tDigest
         this.H7t = t.H7t;
         this.H8t = t.H8t;
     }
+
+    public byte[] getEncodedState()
+    {
+        final int baseSize = getEncodedStateSize();
+        byte[] encoded = new byte[baseSize + 4];
+        populateState(encoded);
+        Pack.intToBigEndian(digestLength * 8, encoded, baseSize);
+        return encoded;
+    }
+
 }