diff options
| -rw-r--r-- | crypto/src/crypto/modes/GCMBlockCipher.cs | 393 |
1 files changed, 202 insertions, 191 deletions
diff --git a/crypto/src/crypto/modes/GCMBlockCipher.cs b/crypto/src/crypto/modes/GCMBlockCipher.cs index 92e4de4a9..16e9e4597 100644 --- a/crypto/src/crypto/modes/GCMBlockCipher.cs +++ b/crypto/src/crypto/modes/GCMBlockCipher.cs @@ -133,14 +133,14 @@ namespace Org.BouncyCastle.Crypto.Modes if (macSizeBits < 32 || macSizeBits > 128 || macSizeBits % 8 != 0) throw new ArgumentException("Invalid value for MAC size: " + macSizeBits); - macSize = macSizeBits / 8; + macSize = macSizeBits / 8; keyParam = aeadParameters.Key; } else if (parameters is ParametersWithIV withIV) { newNonce = withIV.GetIV(); initialAssociatedText = null; - macSize = 16; + macSize = 16; keyParam = (KeyParameter)withIV.Parameters; } else @@ -385,6 +385,13 @@ namespace Org.BouncyCastle.Crypto.Modes bufBlock[bufOff] = input; if (++bufOff == bufBlock.Length) { + Check.OutputLength(output, outOff, BlockSize, "output buffer too short"); + + if (totalLength == 0) + { + InitCipher(); + } + if (forEncryption) { #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER @@ -404,6 +411,8 @@ namespace Org.BouncyCastle.Crypto.Modes Array.Copy(bufBlock, BlockSize, bufBlock, 0, macSize); bufOff = macSize; } + + totalLength += BlockSize; return BlockSize; } return 0; @@ -417,6 +426,13 @@ namespace Org.BouncyCastle.Crypto.Modes bufBlock[bufOff] = input; if (++bufOff == bufBlock.Length) { + Check.OutputLength(output, BlockSize, "output buffer too short"); + + if (totalLength == 0) + { + InitCipher(); + } + if (forEncryption) { EncryptBlock(bufBlock, output); @@ -428,6 +444,8 @@ namespace Org.BouncyCastle.Crypto.Modes Array.Copy(bufBlock, BlockSize, bufBlock, 0, macSize); bufOff = macSize; } + + totalLength += BlockSize; return BlockSize; } return 0; @@ -443,10 +461,21 @@ namespace Org.BouncyCastle.Crypto.Modes #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER return ProcessBytes(input.AsSpan(inOff, len), Spans.FromNullable(output, outOff)); #else - int resultLen = 0; + int resultLen = bufOff + len; if (forEncryption) { + resultLen &= -BlockSize; + if (resultLen > 0) + { + Check.OutputLength(output, outOff, resultLen, "output buffer too short"); + + if (totalLength == 0) + { + InitCipher(); + } + } + if (bufOff > 0) { int available = BlockSize - bufOff; @@ -458,10 +487,12 @@ namespace Org.BouncyCastle.Crypto.Modes } Array.Copy(input, inOff, bufBlock, bufOff, available); - EncryptBlock(bufBlock, 0, output, outOff); inOff += available; len -= available; - resultLen = BlockSize; + + EncryptBlock(bufBlock, 0, output, outOff); + outOff += BlockSize; + //bufOff = 0; } @@ -470,16 +501,16 @@ namespace Org.BouncyCastle.Crypto.Modes while (inOff <= inLimit2) { - EncryptBlocks2(input, inOff, output, outOff + resultLen); + EncryptBlocks2(input, inOff, output, outOff); inOff += BlockSize * 2; - resultLen += BlockSize * 2; + outOff += BlockSize * 2; } if (inOff <= inLimit1) { - EncryptBlock(input, inOff, output, outOff + resultLen); + EncryptBlock(input, inOff, output, outOff); inOff += BlockSize; - resultLen += BlockSize; + //outOff += BlockSize; } bufOff = BlockSize + inLimit1 - inOff; @@ -487,6 +518,18 @@ namespace Org.BouncyCastle.Crypto.Modes } else { + resultLen -= macSize; + resultLen &= -BlockSize; + if (resultLen > 0) + { + Check.OutputLength(output, outOff, resultLen, "output buffer too short"); + + if (totalLength == 0) + { + InitCipher(); + } + } + int available = bufBlock.Length - bufOff; if (len < available) { @@ -498,15 +541,19 @@ namespace Org.BouncyCastle.Crypto.Modes if (bufOff >= BlockSize) { DecryptBlock(bufBlock, 0, output, outOff); - Array.Copy(bufBlock, BlockSize, bufBlock, 0, bufOff -= BlockSize); - resultLen = BlockSize; + outOff += BlockSize; + + bufOff -= BlockSize; + Array.Copy(bufBlock, BlockSize, bufBlock, 0, bufOff); available += BlockSize; if (len < available) { Array.Copy(input, inOff, bufBlock, bufOff, len); bufOff += len; - return resultLen; + + totalLength += BlockSize; + return BlockSize; } } @@ -515,29 +562,31 @@ namespace Org.BouncyCastle.Crypto.Modes available = BlockSize - bufOff; Array.Copy(input, inOff, bufBlock, bufOff, available); - DecryptBlock(bufBlock, 0, output, outOff + resultLen); inOff += available; - resultLen += BlockSize; + + DecryptBlock(bufBlock, 0, output, outOff); + outOff += BlockSize; //bufOff = 0; while (inOff <= inLimit2) { - DecryptBlocks2(input, inOff, output, outOff + resultLen); + DecryptBlocks2(input, inOff, output, outOff); inOff += BlockSize * 2; - resultLen += BlockSize * 2; + outOff += BlockSize * 2; } if (inOff <= inLimit1) { - DecryptBlock(input, inOff, output, outOff + resultLen); + DecryptBlock(input, inOff, output, outOff); inOff += BlockSize; - resultLen += BlockSize; + //outOff += BlockSize; } bufOff = bufBlock.Length + inLimit1 - inOff; Array.Copy(input, inOff, bufBlock, 0, bufOff); } + totalLength += (uint)resultLen; return resultLen; #endif } @@ -547,10 +596,21 @@ namespace Org.BouncyCastle.Crypto.Modes { CheckStatus(); - int resultLen = 0; + int resultLen = bufOff + input.Length; if (forEncryption) { + resultLen &= -BlockSize; + if (resultLen > 0) + { + Check.OutputLength(output, resultLen, "output buffer too short"); + + if (totalLength == 0) + { + InitCipher(); + } + } + if (bufOff > 0) { int available = BlockSize - bufOff; @@ -562,31 +622,42 @@ namespace Org.BouncyCastle.Crypto.Modes } input[..available].CopyTo(bufBlock.AsSpan(bufOff)); - EncryptBlock(bufBlock, output); input = input[available..]; - resultLen = BlockSize; + + EncryptBlock(bufBlock, output); + output = output[BlockSize..]; + //bufOff = 0; } - while (input.Length >= BlockSize * 4) +#if NETCOREAPP3_0_OR_GREATER + if (IsFourWaySupported && input.Length >= BlockSize * 4) { - EncryptBlocks4(input, output[resultLen..]); - input = input[(BlockSize * 4)..]; - resultLen += BlockSize * 4; - } + EncryptBlocks4(ref input, ref output); - if (input.Length >= BlockSize * 2) + if (input.Length >= BlockSize * 2) + { + EncryptBlocks2(input, output); + input = input[(BlockSize * 2)..]; + output = output[(BlockSize * 2)..]; + } + } + else +#endif { - EncryptBlocks2(input, output[resultLen..]); - input = input[(BlockSize * 2)..]; - resultLen += BlockSize * 2; + while (input.Length >= BlockSize * 2) + { + EncryptBlocks2(input, output); + input = input[(BlockSize * 2)..]; + output = output[(BlockSize * 2)..]; + } } if (input.Length >= BlockSize) { - EncryptBlock(input, output[resultLen..]); + EncryptBlock(input, output); input = input[BlockSize..]; - resultLen += BlockSize; + //output = output[BlockSize..]; } bufOff = input.Length; @@ -594,6 +665,18 @@ namespace Org.BouncyCastle.Crypto.Modes } else { + resultLen -= macSize; + resultLen &= -BlockSize; + if (resultLen > 0) + { + Check.OutputLength(output, resultLen, "output buffer too short"); + + if (totalLength == 0) + { + InitCipher(); + } + } + int available = bufBlock.Length - bufOff; if (input.Length < available) { @@ -605,16 +688,19 @@ namespace Org.BouncyCastle.Crypto.Modes if (bufOff >= BlockSize) { DecryptBlock(bufBlock, output); + output = output[BlockSize..]; + bufOff -= BlockSize; bufBlock.AsSpan(0, bufOff).CopyFrom(bufBlock.AsSpan(BlockSize)); - resultLen = BlockSize; available += BlockSize; if (input.Length < available) { input.CopyTo(bufBlock.AsSpan(bufOff)); bufOff += input.Length; - return resultLen; + + totalLength += BlockSize; + return BlockSize; } } @@ -624,36 +710,47 @@ namespace Org.BouncyCastle.Crypto.Modes available = BlockSize - bufOff; input[..available].CopyTo(bufBlock.AsSpan(bufOff)); - DecryptBlock(bufBlock, output[resultLen..]); input = input[available..]; - resultLen += BlockSize; + + DecryptBlock(bufBlock, output); + output = output[BlockSize..]; //bufOff = 0; - while (input.Length >= inLimit4) +#if NETCOREAPP3_0_OR_GREATER + if (IsFourWaySupported && input.Length >= inLimit4) { - DecryptBlocks4(input, output[resultLen..]); - input = input[(BlockSize * 4)..]; - resultLen += BlockSize * 4; - } + DecryptBlocks4(ref input, ref output, inLimit4); - if (input.Length >= inLimit2) + if (input.Length >= inLimit2) + { + DecryptBlocks2(input, output); + input = input[(BlockSize * 2)..]; + output = output[(BlockSize * 2)..]; + } + } + else +#endif { - DecryptBlocks2(input, output[resultLen..]); - input = input[(BlockSize * 2)..]; - resultLen += BlockSize * 2; + while (input.Length >= inLimit2) + { + DecryptBlocks2(input, output); + input = input[(BlockSize * 2)..]; + output = output[(BlockSize * 2)..]; + } } if (input.Length >= inLimit1) { - DecryptBlock(input, output[resultLen..]); + DecryptBlock(input, output); input = input[BlockSize..]; - resultLen += BlockSize; + //output = output[BlockSize..]; } bufOff = input.Length; input.CopyTo(bufBlock); } + totalLength += (uint)resultLen; return resultLen; } #endif @@ -665,11 +762,6 @@ namespace Org.BouncyCastle.Crypto.Modes #else CheckStatus(); - if (totalLength == 0) - { - InitCipher(); - } - int extra = bufOff; if (forEncryption) @@ -686,6 +778,11 @@ namespace Org.BouncyCastle.Crypto.Modes Check.OutputLength(output, outOff, extra, "output buffer too short"); } + if (totalLength == 0) + { + InitCipher(); + } + if (extra > 0) { ProcessPartial(bufBlock, 0, extra, output, outOff); @@ -777,11 +874,6 @@ namespace Org.BouncyCastle.Crypto.Modes { CheckStatus(); - if (totalLength == 0) - { - InitCipher(); - } - int extra = bufOff; if (forEncryption) @@ -798,6 +890,11 @@ namespace Org.BouncyCastle.Crypto.Modes Check.OutputLength(output, extra, "output buffer too short"); } + if (totalLength == 0) + { + InitCipher(); + } + if (extra > 0) { ProcessPartial(bufBlock.AsSpan(0, extra), output); @@ -933,13 +1030,6 @@ namespace Org.BouncyCastle.Crypto.Modes #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER private void DecryptBlock(ReadOnlySpan<byte> input, Span<byte> output) { - Check.OutputLength(output, BlockSize, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - Span<byte> ctrBlock = stackalloc byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -978,19 +1068,10 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize; } private void DecryptBlocks2(ReadOnlySpan<byte> input, Span<byte> output) { - Check.OutputLength(output, BlockSize * 2, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - Span<byte> ctrBlock = stackalloc byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -1069,23 +1150,24 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize * 2; } - private void DecryptBlocks4(ReadOnlySpan<byte> input, Span<byte> output) - { #if NETCOREAPP3_0_OR_GREATER - if (IsFourWaySupported) - { - Check.OutputLength(output, BlockSize * 4, "output buffer too short"); + private void DecryptBlocks4(ref ReadOnlySpan<byte> input, ref Span<byte> output, int limit) + { + if (!IsFourWaySupported) + throw new PlatformNotSupportedException(nameof(DecryptBlocks4)); + if (limit < BlockSize * 4) + throw new ArgumentOutOfRangeException(nameof(limit)); - if (totalLength == 0) - { - InitCipher(); - } + Span<Vector128<byte>> counters = stackalloc Vector128<byte>[4]; + var ctrBlocks = MemoryMarshal.AsBytes(counters); - Span<byte> ctrBlocks = stackalloc byte[BlockSize * 4]; + Vector128<byte> S128 = MemoryMarshal.Read<Vector128<byte>>(S.AsSpan()); + S128 = Ssse3.Shuffle(S128, ReverseBytesMask); + + while (input.Length >= limit) + { GetNextCtrBlocks4(ctrBlocks); var c0 = MemoryMarshal.Read<Vector128<byte>>(input); @@ -1093,29 +1175,23 @@ namespace Org.BouncyCastle.Crypto.Modes var c2 = MemoryMarshal.Read<Vector128<byte>>(input[(BlockSize * 2)..]); var c3 = MemoryMarshal.Read<Vector128<byte>>(input[(BlockSize * 3)..]); - var n0 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks); - var n1 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks[BlockSize..]); - var n2 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks[(BlockSize * 2)..]); - var n3 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks[(BlockSize * 3)..]); - - var p0 = Sse2.Xor(c0, n0); - var p1 = Sse2.Xor(c1, n1); - var p2 = Sse2.Xor(c2, n2); - var p3 = Sse2.Xor(c3, n3); + var p0 = Sse2.Xor(c0, counters[0]); + var p1 = Sse2.Xor(c1, counters[1]); + var p2 = Sse2.Xor(c2, counters[2]); + var p3 = Sse2.Xor(c3, counters[3]); MemoryMarshal.Write(output, ref p0); MemoryMarshal.Write(output[BlockSize..], ref p1); MemoryMarshal.Write(output[(BlockSize * 2)..], ref p2); MemoryMarshal.Write(output[(BlockSize * 3)..], ref p3); - var t0 = MemoryMarshal.Read<Vector128<byte>>(S.AsSpan()); - c0 = Sse2.Xor(c0, t0); - c0 = Ssse3.Shuffle(c0, ReverseBytesMask); c1 = Ssse3.Shuffle(c1, ReverseBytesMask); c2 = Ssse3.Shuffle(c2, ReverseBytesMask); c3 = Ssse3.Shuffle(c3, ReverseBytesMask); + c0 = Sse2.Xor(c0, S128); + GcmUtilities.MultiplyExt(c0.AsUInt64(), HPow[0], out var U0, out var U1, out var U2); GcmUtilities.MultiplyExt(c1.AsUInt64(), HPow[1], out var V0, out var V1, out var V2); GcmUtilities.MultiplyExt(c2.AsUInt64(), HPow[2], out var W0, out var W1, out var W2); @@ -1133,29 +1209,19 @@ namespace Org.BouncyCastle.Crypto.Modes U1 = Sse2.Xor(U1, X1); U2 = Sse2.Xor(U2, X2); - var t2 = GcmUtilities.Reduce3(U0, U1, U2).AsByte(); + S128 = GcmUtilities.Reduce3(U0, U1, U2).AsByte(); - t2 = Ssse3.Shuffle(t2, ReverseBytesMask); - MemoryMarshal.Write(S.AsSpan(), ref t2); - - totalLength += BlockSize * 4; - return; + input = input[(BlockSize * 4)..]; + output = output[(BlockSize * 4)..]; } -#endif - DecryptBlocks2(input, output); - DecryptBlocks2(input[(BlockSize * 2)..], output[(BlockSize * 2)..]); + S128 = Ssse3.Shuffle(S128, ReverseBytesMask); + MemoryMarshal.Write(S.AsSpan(), ref S128); } +#endif private void EncryptBlock(ReadOnlySpan<byte> input, Span<byte> output) { - Check.OutputLength(output, BlockSize, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - Span<byte> ctrBlock = stackalloc byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -1194,19 +1260,10 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize; } private void EncryptBlocks2(ReadOnlySpan<byte> input, Span<byte> output) { - Check.OutputLength(output, BlockSize * 2, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - Span<byte> ctrBlocks = stackalloc byte[BlockSize * 2]; GetNextCtrBlocks2(ctrBlocks); @@ -1285,23 +1342,22 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize * 2; } - private void EncryptBlocks4(ReadOnlySpan<byte> input, Span<byte> output) - { #if NETCOREAPP3_0_OR_GREATER - if (IsFourWaySupported) - { - Check.OutputLength(output, BlockSize * 4, "output buffer too short"); + private void EncryptBlocks4(ref ReadOnlySpan<byte> input, ref Span<byte> output) + { + if (!IsFourWaySupported) + throw new PlatformNotSupportedException(nameof(EncryptBlocks4)); - if (totalLength == 0) - { - InitCipher(); - } + Span<Vector128<byte>> counters = stackalloc Vector128<byte>[4]; + var ctrBlocks = MemoryMarshal.AsBytes(counters); + + Vector128<byte> S128 = MemoryMarshal.Read<Vector128<byte>>(S.AsSpan()); + S128 = Ssse3.Shuffle(S128, ReverseBytesMask); - Span<byte> ctrBlocks = stackalloc byte[BlockSize * 4]; + while (input.Length >= BlockSize * 4) + { GetNextCtrBlocks4(ctrBlocks); var p0 = MemoryMarshal.Read<Vector128<byte>>(input); @@ -1309,29 +1365,23 @@ namespace Org.BouncyCastle.Crypto.Modes var p2 = MemoryMarshal.Read<Vector128<byte>>(input[(BlockSize * 2)..]); var p3 = MemoryMarshal.Read<Vector128<byte>>(input[(BlockSize * 3)..]); - var n0 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks); - var n1 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks[BlockSize..]); - var n2 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks[(BlockSize * 2)..]); - var n3 = MemoryMarshal.Read<Vector128<byte>>(ctrBlocks[(BlockSize * 3)..]); - - var c0 = Sse2.Xor(p0, n0); - var c1 = Sse2.Xor(p1, n1); - var c2 = Sse2.Xor(p2, n2); - var c3 = Sse2.Xor(p3, n3); + var c0 = Sse2.Xor(p0, counters[0]); + var c1 = Sse2.Xor(p1, counters[1]); + var c2 = Sse2.Xor(p2, counters[2]); + var c3 = Sse2.Xor(p3, counters[3]); MemoryMarshal.Write(output, ref c0); MemoryMarshal.Write(output[BlockSize..], ref c1); MemoryMarshal.Write(output[(BlockSize * 2)..], ref c2); MemoryMarshal.Write(output[(BlockSize * 3)..], ref c3); - var t0 = MemoryMarshal.Read<Vector128<byte>>(S.AsSpan()); - c0 = Sse2.Xor(c0, t0); - c0 = Ssse3.Shuffle(c0, ReverseBytesMask); c1 = Ssse3.Shuffle(c1, ReverseBytesMask); c2 = Ssse3.Shuffle(c2, ReverseBytesMask); c3 = Ssse3.Shuffle(c3, ReverseBytesMask); + c0 = Sse2.Xor(c0, S128); + GcmUtilities.MultiplyExt(c0.AsUInt64(), HPow[0], out var U0, out var U1, out var U2); GcmUtilities.MultiplyExt(c1.AsUInt64(), HPow[1], out var V0, out var V1, out var V2); GcmUtilities.MultiplyExt(c2.AsUInt64(), HPow[2], out var W0, out var W1, out var W2); @@ -1349,19 +1399,16 @@ namespace Org.BouncyCastle.Crypto.Modes U1 = Sse2.Xor(U1, X1); U2 = Sse2.Xor(U2, X2); - var t2 = GcmUtilities.Reduce3(U0, U1, U2).AsByte(); + S128 = GcmUtilities.Reduce3(U0, U1, U2).AsByte(); - t2 = Ssse3.Shuffle(t2, ReverseBytesMask); - MemoryMarshal.Write(S.AsSpan(), ref t2); - - totalLength += BlockSize * 4; - return; + input = input[(BlockSize * 4)..]; + output = output[(BlockSize * 4)..]; } -#endif - EncryptBlocks2(input, output); - EncryptBlocks2(input[(BlockSize * 2)..], output[(BlockSize * 2)..]); + S128 = Ssse3.Shuffle(S128, ReverseBytesMask); + MemoryMarshal.Write(S.AsSpan(), ref S128); } +#endif [MethodImpl(MethodImplOptions.AggressiveInlining)] private void GetNextCtrBlock(Span<byte> block) @@ -1458,13 +1505,6 @@ namespace Org.BouncyCastle.Crypto.Modes #else private void DecryptBlock(byte[] inBuf, int inOff, byte[] outBuf, int outOff) { - Check.OutputLength(outBuf, outOff, BlockSize, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - byte[] ctrBlock = new byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -1488,19 +1528,10 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize; } private void DecryptBlocks2(byte[] inBuf, int inOff, byte[] outBuf, int outOff) { - Check.OutputLength(outBuf, outOff, BlockSize * 2, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - byte[] ctrBlock = new byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -1549,19 +1580,10 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize * 2; } private void EncryptBlock(byte[] inBuf, int inOff, byte[] outBuf, int outOff) { - Check.OutputLength(outBuf, outOff, BlockSize, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - byte[] ctrBlock = new byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -1585,19 +1607,10 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize; } private void EncryptBlocks2(byte[] inBuf, int inOff, byte[] outBuf, int outOff) { - Check.OutputLength(outBuf, outOff, BlockSize * 2, "output buffer too short"); - - if (totalLength == 0) - { - InitCipher(); - } - byte[] ctrBlock = new byte[BlockSize]; GetNextCtrBlock(ctrBlock); @@ -1646,8 +1659,6 @@ namespace Org.BouncyCastle.Crypto.Modes } } multiplier.MultiplyH(S); - - totalLength += BlockSize * 2; } private void GetNextCtrBlock(byte[] block) |