using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Utilities; namespace Org.BouncyCastle.Tls.Crypto.Impl.BC { internal class BcSsl3Hmac : TlsHmac, TlsMac { private const byte IPAD_BYTE = 54; private const byte OPAD_BYTE = 92; private static readonly byte[] IPAD = GenPad(54, 48); private static readonly byte[] OPAD = GenPad(92, 48); private readonly IDigest m_digest; private readonly int m_padLength; private byte[] m_secret; public virtual int InternalBlockSize => m_digest.GetByteLength(); public virtual int MacLength => m_digest.GetDigestSize(); internal BcSsl3Hmac(IDigest digest) { m_digest = digest; if (digest.GetDigestSize() == 20) m_padLength = 40; else m_padLength = 48; } public virtual void SetKey(byte[] key, int keyOff, int keyLen) { m_secret = TlsUtilities.CopyOfRangeExact(key, keyOff, keyOff + keyLen); Reset(); } public virtual void Update(byte[] input, int inOff, int len) { m_digest.BlockUpdate(input, inOff, len); } public virtual byte[] CalculateMac() { byte[] array = new byte[m_digest.GetDigestSize()]; DoFinal(array, 0); return array; } public virtual void CalculateMac(byte[] output, int outOff) { DoFinal(output, outOff); } public virtual void Reset() { m_digest.Reset(); m_digest.BlockUpdate(m_secret, 0, m_secret.Length); m_digest.BlockUpdate(IPAD, 0, m_padLength); } private void DoFinal(byte[] output, int outOff) { byte[] array = new byte[m_digest.GetDigestSize()]; m_digest.DoFinal(array, 0); m_digest.BlockUpdate(m_secret, 0, m_secret.Length); m_digest.BlockUpdate(OPAD, 0, m_padLength); m_digest.BlockUpdate(array, 0, array.Length); m_digest.DoFinal(output, outOff); Reset(); } private static byte[] GenPad(byte b, int count) { byte[] obj = new byte[count]; Arrays.Fill(obj, b); return obj; } } }