/// <summary>
/// Return a copy of the passed in secret key, encrypted using a new password
/// and the passed in algorithm.
/// </summary>
/// <param name="key">The PgpSecretKey to be copied.</param>
/// <param name="oldPassPhrase">The current password for the key.</param>
/// <param name="newPassPhrase">The new password for the key.</param>
/// <param name="newEncAlgorithm">The algorithm to be used for the encryption.</param>
/// <param name="rand">Source of randomness.</param>
public static PgpSecretKey CopyWithNewPassword(
PgpSecretKey key,
char[] oldPassPhrase,
char[] newPassPhrase,
SymmetricKeyAlgorithmTag newEncAlgorithm,
SecureRandom rand)
{
byte[] rawKeyData = key.ExtractKeyData(oldPassPhrase);
int s2kUsage = key.secret.S2kUsage;
byte[] iv = null;
S2k s2k = null;
byte[] keyData;
if (newEncAlgorithm == SymmetricKeyAlgorithmTag.Null)
{
s2kUsage = SecretKeyPacket.UsageNone;
if (key.secret.S2kUsage == SecretKeyPacket.UsageSha1) // SHA-1 hash, need to rewrite Checksum
{
keyData = new byte[rawKeyData.Length - 18];
Array.Copy(rawKeyData, 0, keyData, 0, keyData.Length - 2);
byte[] check = Checksum(false, keyData, keyData.Length - 2);
keyData[keyData.Length - 2] = check[0];
keyData[keyData.Length - 1] = check[1];
}
else
{
keyData = rawKeyData;
}
}
else
{
try
{
keyData = EncryptKeyData(rawKeyData, newEncAlgorithm, newPassPhrase, rand, out s2k, out iv);
}
catch (PgpException e)
{
throw e;
}
catch (Exception e)
{
throw new PgpException("Exception encrypting key", e);
}
}
SecretKeyPacket secret;
if (key.secret is SecretSubkeyPacket)
{
secret = new SecretSubkeyPacket(key.secret.PublicKeyPacket,
newEncAlgorithm, s2kUsage, s2k, iv, keyData);
}
else
{
secret = new SecretKeyPacket(key.secret.PublicKeyPacket,
newEncAlgorithm, s2kUsage, s2k, iv, keyData);
}
return(new PgpSecretKey(secret, key.pub));
}
