public static KeyParameter MakeKeyFromPassPhrase(SymmetricKeyAlgorithmTag algorithm, IS2k s2k, char[] passPhrase)
{
var keySize = GetKeySize(algorithm);
var pBytes = Strings.ToByteArray(new string(passPhrase));
var keyBytes = new byte[(keySize + 7) / 8];
var generatedBytes = 0;
var loopCount = 0;
while (generatedBytes < keyBytes.Length)
{
IDigest digest;
if (s2k != null)
{
var digestName = GetDigestName(s2k.HashAlgorithm);
try
{
digest = DigestUtilities.GetDigest(digestName);
}
catch (Exception e)
{
throw new PgpException("can't find S2k digest", e);
}
for (var i = 0; i != loopCount; i++)
{
digest.Update(0);
}
var iv = s2k.GetIV();
switch (s2k.Type)
{
case S2k.Simple:
digest.BlockUpdate(pBytes, 0, pBytes.Length);
break;
case S2k.Salted:
digest.BlockUpdate(iv, 0, iv.Length);
digest.BlockUpdate(pBytes, 0, pBytes.Length);
break;
case S2k.SaltedAndIterated:
var count = s2k.IterationCount;
digest.BlockUpdate(iv, 0, iv.Length);
digest.BlockUpdate(pBytes, 0, pBytes.Length);
count -= iv.Length + pBytes.Length;
while (count > 0)
{
if (count < iv.Length)
{
digest.BlockUpdate(iv, 0, (int)count);
break;
}
digest.BlockUpdate(iv, 0, iv.Length);
count -= iv.Length;
if (count < pBytes.Length)
{
digest.BlockUpdate(pBytes, 0, (int)count);
count = 0;
}
else
{
digest.BlockUpdate(pBytes, 0, pBytes.Length);
count -= pBytes.Length;
}
}
break;
default:
throw new PgpException("unknown S2k type: " + s2k.Type);
}
}
else
{
try
{
digest = DigestUtilities.GetDigest("MD5");
for (var i = 0; i != loopCount; i++)
{
digest.Update(0);
}
digest.BlockUpdate(pBytes, 0, pBytes.Length);
}
catch (Exception e)
{
throw new PgpException("can't find MD5 digest", e);
}
}
var dig = DigestUtilities.DoFinal(digest);
if (dig.Length > (keyBytes.Length - generatedBytes))
{
Array.Copy(dig, 0, keyBytes, generatedBytes, keyBytes.Length - generatedBytes);
}
else
{
Array.Copy(dig, 0, keyBytes, generatedBytes, dig.Length);
}
generatedBytes += dig.Length;
loopCount++;
}
Array.Clear(pBytes, 0, pBytes.Length);
return(MakeKey(algorithm, keyBytes));
}
public static KeyParameter MakeKeyFromPassPhrase(SymmetricKeyAlgorithmTag algorithm, IS2k s2k, char[] passPhrase)
{
var keySize = GetKeySize(algorithm);
var pBytes = Strings.ToByteArray(new string(passPhrase));
var keyBytes = new byte[(keySize + 7) / 8];
var generatedBytes = 0;
var loopCount = 0;
while (generatedBytes < keyBytes.Length)
{
IDigest digest;
if (s2k != null)
{
var digestName = GetDigestName(s2k.HashAlgorithm);
try
{
digest = DigestUtilities.GetDigest(digestName);
}
catch (Exception e)
{
throw new PgpException("can't find S2k digest", e);
}
for (var i = 0; i != loopCount; i++)
{
digest.Update(0);
}
var iv = s2k.GetIV();
switch (s2k.Type)
{
case S2k.Simple:
digest.BlockUpdate(pBytes, 0, pBytes.Length);
break;
case S2k.Salted:
digest.BlockUpdate(iv, 0, iv.Length);
digest.BlockUpdate(pBytes, 0, pBytes.Length);
break;
case S2k.SaltedAndIterated:
var count = s2k.IterationCount;
digest.BlockUpdate(iv, 0, iv.Length);
digest.BlockUpdate(pBytes, 0, pBytes.Length);
count -= iv.Length + pBytes.Length;
while (count > 0)
{
if (count < iv.Length)
{
digest.BlockUpdate(iv, 0, (int)count);
break;
}
digest.BlockUpdate(iv, 0, iv.Length);
count -= iv.Length;
if (count < pBytes.Length)
{
digest.BlockUpdate(pBytes, 0, (int)count);
count = 0;
}
else
{
digest.BlockUpdate(pBytes, 0, pBytes.Length);
count -= pBytes.Length;
}
}
break;
default:
throw new PgpException("unknown S2k type: " + s2k.Type);
}
}
else
{
try
{
digest = DigestUtilities.GetDigest("MD5");
for (var i = 0; i != loopCount; i++)
{
digest.Update(0);
}
digest.BlockUpdate(pBytes, 0, pBytes.Length);
}
catch (Exception e)
{
throw new PgpException("can't find MD5 digest", e);
}
}
var dig = DigestUtilities.DoFinal(digest);
if (dig.Length > (keyBytes.Length - generatedBytes))
{
Array.Copy(dig, 0, keyBytes, generatedBytes, keyBytes.Length - generatedBytes);
}
else
{
Array.Copy(dig, 0, keyBytes, generatedBytes, dig.Length);
}
generatedBytes += dig.Length;
loopCount++;
}
Array.Clear(pBytes, 0, pBytes.Length);
return MakeKey(algorithm, keyBytes);
}
