org.bouncycastle.openpgp.operator.PGPUtil Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of bcpg-jdk15on Show documentation
The Bouncy Castle Java API for handling the OpenPGP protocol. This jar contains the OpenPGP API for JDK 1.5 to JDK 1.7. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.
There is a newer version: 1.70
Show newest version
package org.bouncycastle.openpgp.operator;

import java.io.IOException;
import java.io.OutputStream;

import org.bouncycastle.bcpg.HashAlgorithmTags;
import org.bouncycastle.bcpg.S2K;
import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.util.Strings;

/**
 * Basic utility class
 */
class PGPUtil
    implements HashAlgorithmTags
{
    static byte[] makeKeyFromPassPhrase(
        PGPDigestCalculator digestCalculator,
        int     algorithm,
        S2K     s2k,
        char[]  passPhrase)
        throws PGPException
    {
        String    algName = null;
        int        keySize = 0;

        switch (algorithm)
        {
        case SymmetricKeyAlgorithmTags.TRIPLE_DES:
            keySize = 192;
            algName = "DES_EDE";
            break;
        case SymmetricKeyAlgorithmTags.IDEA:
            keySize = 128;
            algName = "IDEA";
            break;
        case SymmetricKeyAlgorithmTags.CAST5:
            keySize = 128;
            algName = "CAST5";
            break;
        case SymmetricKeyAlgorithmTags.BLOWFISH:
            keySize = 128;
            algName = "Blowfish";
            break;
        case SymmetricKeyAlgorithmTags.SAFER:
            keySize = 128;
            algName = "SAFER";
            break;
        case SymmetricKeyAlgorithmTags.DES:
            keySize = 64;
            algName = "DES";
            break;
        case SymmetricKeyAlgorithmTags.AES_128:
            keySize = 128;
            algName = "AES";
            break;
        case SymmetricKeyAlgorithmTags.AES_192:
            keySize = 192;
            algName = "AES";
            break;
        case SymmetricKeyAlgorithmTags.AES_256:
            keySize = 256;
            algName = "AES";
            break;
        case SymmetricKeyAlgorithmTags.TWOFISH:
            keySize = 256;
            algName = "Twofish";
            break;
        default:
            throw new PGPException("unknown symmetric algorithm: " + algorithm);
        }

        byte[]    pBytes = Strings.toUTF8ByteArray(passPhrase);
        byte[]    keyBytes = new byte[(keySize + 7) / 8];

        int    generatedBytes = 0;
        int    loopCount = 0;

        if (s2k != null)
        {
            if (s2k.getHashAlgorithm() != digestCalculator.getAlgorithm())
            {
                throw new PGPException("s2k/digestCalculator mismatch");
            }
        }
        else
        {
            if (digestCalculator.getAlgorithm() != HashAlgorithmTags.MD5)
            {
                throw new PGPException("digestCalculator not for MD5");
            }
        }

        OutputStream dOut = digestCalculator.getOutputStream();

        try
        {
            while (generatedBytes < keyBytes.length)
            {
                if (s2k != null)
                {
                    for (int i = 0; i != loopCount; i++)
                    {
                        dOut.write(0);
                    }

                    byte[]    iv = s2k.getIV();

                    switch (s2k.getType())
                    {
                    case S2K.SIMPLE:
                        dOut.write(pBytes);
                        break;
                    case S2K.SALTED:
                        dOut.write(iv);
                        dOut.write(pBytes);
                        break;
                    case S2K.SALTED_AND_ITERATED:
                        long    count = s2k.getIterationCount();
                        dOut.write(iv);
                        dOut.write(pBytes);

                        count -= iv.length + pBytes.length;

                        while (count > 0)
                        {
                            if (count < iv.length)
                            {
                                dOut.write(iv, 0, (int)count);
                                break;
                            }
                            else
                            {
                                dOut.write(iv);
                                count -= iv.length;
                            }

                            if (count < pBytes.length)
                            {
                                dOut.write(pBytes, 0, (int)count);
                                count = 0;
                            }
                            else
                            {
                                dOut.write(pBytes);
                                count -= pBytes.length;
                            }
                        }
                        break;
                    default:
                        throw new PGPException("unknown S2K type: " + s2k.getType());
                    }
                }
                else
                {
                    for (int i = 0; i != loopCount; i++)
                    {
                        dOut.write((byte)0);
                    }

                    dOut.write(pBytes);
                }

                dOut.close();

                byte[]    dig = digestCalculator.getDigest();

                if (dig.length > (keyBytes.length - generatedBytes))
                {
                    System.arraycopy(dig, 0, keyBytes, generatedBytes, keyBytes.length - generatedBytes);
                }
                else
                {
                    System.arraycopy(dig, 0, keyBytes, generatedBytes, dig.length);
                }

                generatedBytes += dig.length;

                loopCount++;
            }
        }
        catch (IOException e)
        {
            throw new PGPException("exception calculating digest: " + e.getMessage(), e);
        }

        for (int i = 0; i != pBytes.length; i++)
        {
            pBytes[i] = 0;
        }

        return keyBytes;
    }

    public static byte[] makeKeyFromPassPhrase(
        PGPDigestCalculatorProvider digCalcProvider,
        int     algorithm,
        S2K     s2k,
        char[]  passPhrase)
        throws PGPException
    {
        PGPDigestCalculator digestCalculator;

        if (s2k != null)
        {
            digestCalculator = digCalcProvider.get(s2k.getHashAlgorithm());
        }
        else
        {
            digestCalculator = digCalcProvider.get(HashAlgorithmTags.MD5);
        }

        return makeKeyFromPassPhrase(digestCalculator, algorithm, s2k, passPhrase);
    }
}