org.bouncycastle.tls.crypto.impl.jcajce.JceBlockCipherImpl Maven / Gradle / Ivy

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The Bouncy Castle Java APIs for the TLS, including a JSSE provider. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified and used appropriately.

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package org.bouncycastle.tls.crypto.impl.jcajce;

import java.security.GeneralSecurityException;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

import org.bouncycastle.tls.crypto.impl.TlsBlockCipherImpl;

/**
 * A basic wrapper for a JCE Cipher class to provide the needed block cipher functionality for TLS.
 */
public class JceBlockCipherImpl
    implements TlsBlockCipherImpl
{
    private static final int BUF_SIZE = 32 * 1024;

    private final int cipherMode;
    private final Cipher cipher;
    private final String algorithm;
    private final int keySize;

    private SecretKey key;

    public JceBlockCipherImpl(Cipher cipher, String algorithm, int keySize, boolean isEncrypting)
        throws GeneralSecurityException
    {
        this.cipher = cipher;
        this.algorithm = algorithm;
        this.keySize = keySize;
        this.cipherMode = (isEncrypting) ? Cipher.ENCRYPT_MODE : Cipher.DECRYPT_MODE;
    }

    public void setKey(byte[] key, int keyOff, int keyLen)
    {
        if (keySize != keyLen)
        {
            throw new IllegalStateException();
        }

        this.key = new SecretKeySpec(key, keyOff, keyLen, algorithm);
    }

    public void init(byte[] iv, int ivOff, int ivLen)
    {
        try
        {
            cipher.init(cipherMode, key, new IvParameterSpec(iv, ivOff, ivLen));
        }
        catch (GeneralSecurityException e)
        {
            throw Exceptions.illegalStateException(e.getMessage(), e);
        }
    }

    public int doFinal(byte[] input, int inputOffset, int inputLength, byte[] output, int outputOffset)
    {
        try
        {
            // to avoid performance issue in FIPS jar  1.0.0-1.0.2
            int totLen = 0;
            while (inputLength > BUF_SIZE)
            {
                totLen += cipher.update(input, inputOffset, BUF_SIZE, output, outputOffset + totLen);

                inputOffset += BUF_SIZE;
                inputLength -= BUF_SIZE;
            }

            totLen += cipher.update(input, inputOffset, inputLength, output, outputOffset + totLen);
            totLen += cipher.doFinal(output, outputOffset + totLen);

            return totLen;
        }
        catch (GeneralSecurityException e)
        {
            throw Exceptions.illegalStateException(e.getMessage(), e);
        }
    }

    public int getBlockSize()
    {
        return cipher.getBlockSize();
    }
}