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package org.spongycastle.openpgp.operator;
import java.security.SecureRandom;
import org.spongycastle.bcpg.ContainedPacket;
import org.spongycastle.bcpg.S2K;
import org.spongycastle.bcpg.SymmetricKeyEncSessionPacket;
import org.spongycastle.openpgp.PGPException;
public abstract class PBEKeyEncryptionMethodGenerator
extends PGPKeyEncryptionMethodGenerator
{
private char[] passPhrase;
private PGPDigestCalculator s2kDigestCalculator;
private S2K s2k;
private SecureRandom random;
private int s2kCount;
protected PBEKeyEncryptionMethodGenerator(
char[] passPhrase,
PGPDigestCalculator s2kDigestCalculator)
{
this(passPhrase, s2kDigestCalculator, 0x60);
}
protected PBEKeyEncryptionMethodGenerator(
char[] passPhrase,
PGPDigestCalculator s2kDigestCalculator,
int s2kCount)
{
this.passPhrase = passPhrase;
this.s2kDigestCalculator = s2kDigestCalculator;
if (s2kCount < 0 || s2kCount > 0xff)
{
throw new IllegalArgumentException("s2kCount value outside of range 0 to 255.");
}
this.s2kCount = s2kCount;
}
public PBEKeyEncryptionMethodGenerator setSecureRandom(SecureRandom random)
{
this.random = random;
return this;
}
public byte[] getKey(int encAlgorithm)
throws PGPException
{
if (s2k == null)
{
byte[] iv = new byte[8];
if (random == null)
{
random = new SecureRandom();
}
random.nextBytes(iv);
s2k = new S2K(s2kDigestCalculator.getAlgorithm(), iv, s2kCount);
}
return PGPUtil.makeKeyFromPassPhrase(s2kDigestCalculator, encAlgorithm, s2k, passPhrase);
}
public ContainedPacket generate(int encAlgorithm, byte[] sessionInfo)
throws PGPException
{
byte[] key = getKey(encAlgorithm);
if (sessionInfo == null)
{
return new SymmetricKeyEncSessionPacket(encAlgorithm, s2k, null);
}
//
// the passed in session info has the an RSA/ElGamal checksum added to it, for PBE this is not included.
//
byte[] nSessionInfo = new byte[sessionInfo.length - 2];
System.arraycopy(sessionInfo, 0, nSessionInfo, 0, nSessionInfo.length);
return new SymmetricKeyEncSessionPacket(encAlgorithm, s2k, encryptSessionInfo(encAlgorithm, key, nSessionInfo));
}
abstract protected byte[] encryptSessionInfo(int encAlgorithm, byte[] key, byte[] sessionInfo)
throws PGPException;
}
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