package org.bouncycastle.pqc.crypto.mceliece;
import org.bouncycastle.crypto.CipherParameters;
import org.bouncycastle.crypto.Digest;
import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.ParametersWithRandom;
import org.bouncycastle.pqc.crypto.MessageEncryptor;
// TODO should implement some interface?
public class McEliecePointchevalDigestCipher
{
private final Digest messDigest;
private final MessageEncryptor mcElieceCCA2Cipher;
private boolean forEncrypting;
public McEliecePointchevalDigestCipher(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("McEliecePointchevalDigestCipher 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("McEliecePointchevalDigestCipher 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();
}
}