diff options
Diffstat (limited to 'crypto/src/security/SecureRandom.cs')
| -rw-r--r-- | crypto/src/security/SecureRandom.cs | 34 |
1 files changed, 18 insertions, 16 deletions
diff --git a/crypto/src/security/SecureRandom.cs b/crypto/src/security/SecureRandom.cs index ac9d98158..c91b5ee91 100644 --- a/crypto/src/security/SecureRandom.cs +++ b/crypto/src/security/SecureRandom.cs @@ -22,13 +22,19 @@ namespace Org.BouncyCastle.Security { if (master[0] == null) { - IRandomGenerator gen = sha256Generator; - gen = new ReversedWindowGenerator(gen, 32); - SecureRandom sr = master[0] = new SecureRandom(gen); + SecureRandom sr = master[0] = new SecureRandom(sha256Generator); + // Even though Ticks has at most 8 or 14 bits of entropy, there's no harm in adding it. sr.SetSeed(DateTime.Now.Ticks); - sr.SetSeed(new ThreadedSeedGenerator().GenerateSeed(24, true)); - sr.GenerateSeed(1 + sr.Next(32)); + // In addition to Ticks and ThreadedSeedGenerator, also seed from CryptoApiRandomGenerator + CryptoApiRandomGenerator systemRNG = new CryptoApiRandomGenerator(); + byte[] systemSeed = new byte[32]; + systemRNG.NextBytes(systemSeed); + sr.SetSeed(systemSeed); + Array.Clear(systemSeed,0,systemSeed.Length); + // 32 will be enough when ThreadedSeedGenerator is fixed. Until then, ThreadedSeedGenerator returns low + // entropy, and this is not sufficient to be secure. http://www.bouncycastle.org/csharpdevmailarchive/msg00814.html + sr.SetSeed(new ThreadedSeedGenerator().GenerateSeed(32, true)); } return master[0]; @@ -38,24 +44,20 @@ namespace Org.BouncyCastle.Security public static SecureRandom GetInstance( string algorithm) { - // TODO Compared to JDK, we don't auto-seed if the client forgets - problem? - // TODO Support all digests more generally, by stripping PRNG and calling DigestUtilities? string drgName = Platform.ToUpperInvariant(algorithm); - IRandomGenerator drg = null; if (drgName == "SHA1PRNG") { - drg = sha1Generator; + SecureRandom newPrng = new SecureRandom(sha1Generator); + newPrng.SetSeed(GetSeed(20)); + return newPrng; } else if (drgName == "SHA256PRNG") { - drg = sha256Generator; - } - - if (drg != null) - { - return new SecureRandom(drg); + SecureRandom newPrng = new SecureRandom(sha256Generator); + newPrng.SetSeed(GetSeed(32)); + return newPrng; } throw new ArgumentException("Unrecognised PRNG algorithm: " + algorithm, "algorithm"); @@ -72,7 +74,7 @@ namespace Org.BouncyCastle.Security public SecureRandom() : this(sha1Generator) { - SetSeed(GetSeed(8)); + SetSeed(GetSeed(20)); // 20 bytes because this is sha1Generator } public SecureRandom( |