1 files changed, 128 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/pqc/crypto/mceliece/McElieceFujisakiDigestCipher.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/pqc/crypto/mceliece/McElieceFujisakiDigestCipher.java
new file mode 100644
index 000000000..9a5577ce0
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/pqc/crypto/mceliece/McElieceFujisakiDigestCipher.java
@@ -0,0 +1,128 @@
+package org.spongycastle.pqc.crypto.mceliece;
+
+
+import org.spongycastle.crypto.CipherParameters;
+import org.spongycastle.crypto.Digest;
+import org.spongycastle.crypto.params.AsymmetricKeyParameter;
+import org.spongycastle.crypto.params.ParametersWithRandom;
+import org.spongycastle.pqc.crypto.MessageEncryptor;
+
+// TODO should implement some interface?
+public class McElieceFujisakiDigestCipher
+{
+
+    private final Digest messDigest;
+
+    private final MessageEncryptor mcElieceCCA2Cipher;
+
+    private boolean forEncrypting;
+
+
+    public McElieceFujisakiDigestCipher(MessageEncryptor mcElieceCCA2Cipher, Digest messDigest)
+    {
+        this.mcElieceCCA2Cipher = mcElieceCCA2Cipher;
+        this.messDigest = messDigest;
+    }
+
+
+    public void init(boolean forEncrypting,
+                     CipherParameters param)
+    {
+
+        this.forEncrypting = forEncrypting;
+        AsymmetricKeyParameter k;
+
+        if (param instanceof ParametersWithRandom)
+        {
+            k = (AsymmetricKeyParameter)((ParametersWithRandom)param).getParameters();
+        }
+        else
+        {
+            k = (AsymmetricKeyParameter)param;
+        }
+
+        if (forEncrypting && k.isPrivate())
+        {
+            throw new IllegalArgumentException("Encrypting Requires Public Key.");
+        }
+
+        if (!forEncrypting && !k.isPrivate())
+        {
+            throw new IllegalArgumentException("Decrypting Requires Private Key.");
+        }
+
+        reset();
+
+        mcElieceCCA2Cipher.init(forEncrypting, param);
+    }
+
+
+    public byte[] messageEncrypt()
+    {
+        if (!forEncrypting)
+        {
+            throw new IllegalStateException("McElieceFujisakiDigestCipher not initialised for encrypting.");
+        }
+
+        byte[] hash = new byte[messDigest.getDigestSize()];
+        messDigest.doFinal(hash, 0);
+        byte[] enc = null;
+
+        try
+        {
+            enc = mcElieceCCA2Cipher.messageEncrypt(hash);
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace();
+        }
+
+
+        return enc;
+    }
+
+
+    public byte[] messageDecrypt(byte[] ciphertext)
+    {
+        byte[] output = null;
+        if (forEncrypting)
+        {
+            throw new IllegalStateException("McElieceFujisakiDigestCipher not initialised for decrypting.");
+        }
+
+
+        try
+        {
+            output = mcElieceCCA2Cipher.messageDecrypt(ciphertext);
+        }
+        catch (Exception e)
+        {
+            e.printStackTrace();
+        }
+
+
+        return output;
+    }
+
+
+    public void update(byte b)
+    {
+        messDigest.update(b);
+
+    }
+
+    public void update(byte[] in, int off, int len)
+    {
+        messDigest.update(in, off, len);
+
+    }
+
+
+    public void reset()
+    {
+        messDigest.reset();
+
+    }
+
+
+}