SHA256Managed.cs source code in C# .NET

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Code:

/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / clr / src / BCL / System / Security / Cryptography / SHA256Managed.cs / 1305376 / SHA256Managed.cs

                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
// [....]
// 
 
//
// SHA256Managed.cs 
//
// C# implementation of the proposed SHA-256 hash algorithm
//
 
namespace System.Security.Cryptography {
    using System; 
    using System.Security; 
    using System.Diagnostics.Contracts;
 
    [System.Runtime.InteropServices.ComVisible(true)]
    public class SHA256Managed : SHA256
    {
        private byte[]   _buffer; 
        private long     _count; // Number of bytes in the hashed message
        private UInt32[] _stateSHA256; 
        private UInt32[] _W; 

        // 
        // public constructors
        //

        public SHA256Managed() 
        {
#if FEATURE_CRYPTO 
            if (CryptoConfig.AllowOnlyFipsAlgorithms) 
                throw new InvalidOperationException(Environment.GetResourceString("Cryptography_NonCompliantFIPSAlgorithm"));
            Contract.EndContractBlock(); 
#endif // FEATURE_CRYPTO

            _stateSHA256 = new UInt32[8];
            _buffer = new byte[64]; 
            _W = new UInt32[64];
 
            InitializeState(); 
        }
 
        //
        // public methods
        //
 
        public override void Initialize() {
            InitializeState(); 
 
            // Zeroize potentially sensitive information.
            Array.Clear(_buffer, 0, _buffer.Length); 
            Array.Clear(_W, 0, _W.Length);
        }

        protected override void HashCore(byte[] rgb, int ibStart, int cbSize) { 
            _HashData(rgb, ibStart, cbSize);
        } 
 
        protected override byte[] HashFinal() {
            return _EndHash(); 
        }

        //
        // private methods 
        //
 
        private void InitializeState() { 
            _count = 0;
 
            _stateSHA256[0] = 0x6a09e667;
            _stateSHA256[1] = 0xbb67ae85;
            _stateSHA256[2] = 0x3c6ef372;
            _stateSHA256[3] = 0xa54ff53a; 
            _stateSHA256[4] = 0x510e527f;
            _stateSHA256[5] = 0x9b05688c; 
            _stateSHA256[6] = 0x1f83d9ab; 
            _stateSHA256[7] = 0x5be0cd19;
        } 

        /* SHA256 block update operation. Continues an SHA message-digest
           operation, processing another message block, and updating the
           context. 
           */
 
        [System.Security.SecuritySafeCritical]  // auto-generated 
        private unsafe void _HashData(byte[] partIn, int ibStart, int cbSize)
        { 
            int bufferLen;
            int partInLen = cbSize;
            int partInBase = ibStart;
 
            /* Compute length of buffer */
            bufferLen = (int) (_count & 0x3f); 
 
            /* Update number of bytes */
            _count += partInLen; 

            fixed (uint* stateSHA256 = _stateSHA256) {
                fixed (byte* buffer = _buffer) {
                    fixed (uint* expandedBuffer = _W) { 
                        if ((bufferLen > 0) && (bufferLen + partInLen >= 64)) {
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, bufferLen, 64 - bufferLen); 
                            partInBase += (64 - bufferLen); 
                            partInLen -= (64 - bufferLen);
                            SHATransform(expandedBuffer, stateSHA256, buffer); 
                            bufferLen = 0;
                        }

                        /* Copy input to temporary buffer and hash */ 
                        while (partInLen >= 64) {
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, 0, 64); 
                            partInBase += 64; 
                            partInLen -= 64;
                            SHATransform(expandedBuffer, stateSHA256, buffer); 
                        }

                        if (partInLen > 0) {
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, bufferLen, partInLen); 
                        }
                    } 
                } 
            }
        } 

        /* SHA256 finalization. Ends an SHA256 message-digest operation, writing
           the message digest.
           */ 

        private byte[] _EndHash() 
        { 
            byte[]         pad;
            int            padLen; 
            long           bitCount;
            byte[]         hash = new byte[32]; // HashSizeValue = 256

            /* Compute padding: 80 00 00 ... 00 00  
             */
 
            padLen = 64 - (int)(_count & 0x3f); 
            if (padLen <= 8)
                padLen += 64; 

            pad = new byte[padLen];
            pad[0] = 0x80;
 
            //  Convert count to bit count
            bitCount = _count * 8; 
 
            pad[padLen-8] = (byte) ((bitCount >> 56) & 0xff);
            pad[padLen-7] = (byte) ((bitCount >> 48) & 0xff); 
            pad[padLen-6] = (byte) ((bitCount >> 40) & 0xff);
            pad[padLen-5] = (byte) ((bitCount >> 32) & 0xff);
            pad[padLen-4] = (byte) ((bitCount >> 24) & 0xff);
            pad[padLen-3] = (byte) ((bitCount >> 16) & 0xff); 
            pad[padLen-2] = (byte) ((bitCount >> 8) & 0xff);
            pad[padLen-1] = (byte) ((bitCount >> 0) & 0xff); 
 
            /* Digest padding */
            _HashData(pad, 0, pad.Length); 

            /* Store digest */
            Utils.DWORDToBigEndian (hash, _stateSHA256, 8);
 
            HashValue = hash;
            return hash; 
        } 

        private readonly static UInt32[] _K = { 
            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
            0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
            0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 
            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
            0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 
            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 
            0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 
            0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
            0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
            0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 
            0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 
            0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2 
        };
 
        [System.Security.SecurityCritical]  // auto-generated
        private static unsafe void SHATransform (uint* expandedBuffer, uint* state, byte* block)
        {
            UInt32 a, b, c, d, e, f, h, g; 
            UInt32 aa, bb, cc, dd, ee, ff, hh, gg;
            UInt32 T1; 
 
            a = state[0];
            b = state[1]; 
            c = state[2];
            d = state[3];
            e = state[4];
            f = state[5]; 
            g = state[6];
            h = state[7]; 
 
            // fill in the first 16 bytes of W.
            Utils.DWORDFromBigEndian(expandedBuffer, 16, block); 
            SHA256Expand(expandedBuffer);

            /* Apply the SHA256 compression function */
            // We are trying to be smart here and avoid as many copies as we can 
            // The perf gain with this method over the straightforward modify and shift
            // forward is >= 20%, so it's worth the pain 
            for (int j=0; j<64; ) { 
                T1 = h + Sigma_1(e) + Ch(e,f,g) + _K[j] + expandedBuffer[j];
                ee = d + T1; 
                aa = T1 + Sigma_0(a) + Maj(a,b,c);
                j++;

                T1 = g + Sigma_1(ee) + Ch(ee,e,f) + _K[j] + expandedBuffer[j]; 
                ff = c + T1;
                bb = T1 + Sigma_0(aa) + Maj(aa,a,b); 
                j++; 

                T1 = f + Sigma_1(ff) + Ch(ff,ee,e) + _K[j] + expandedBuffer[j]; 
                gg = b + T1;
                cc = T1 + Sigma_0(bb) + Maj(bb,aa,a);
                j++;
 
                T1 = e + Sigma_1(gg) + Ch(gg,ff,ee) + _K[j] + expandedBuffer[j];
                hh = a + T1; 
                dd = T1 + Sigma_0(cc) + Maj(cc,bb,aa); 
                j++;
 
                T1 = ee + Sigma_1(hh) + Ch(hh,gg,ff) + _K[j] + expandedBuffer[j];
                h = aa + T1;
                d = T1 + Sigma_0(dd) + Maj(dd,cc,bb);
                j++; 

                T1 = ff + Sigma_1(h) + Ch(h,hh,gg) + _K[j] + expandedBuffer[j]; 
                g = bb + T1; 
                c = T1 + Sigma_0(d) + Maj(d,dd,cc);
                j++; 

                T1 = gg + Sigma_1(g) + Ch(g,h,hh) + _K[j] + expandedBuffer[j];
                f = cc + T1;
                b = T1 + Sigma_0(c) + Maj(c,d,dd); 
                j++;
 
                T1 = hh + Sigma_1(f) + Ch(f,g,h) + _K[j] + expandedBuffer[j]; 
                e = dd + T1;
                a = T1 + Sigma_0(b) + Maj(b,c,d); 
                j++;
            }

            state[0] += a; 
            state[1] += b;
            state[2] += c; 
            state[3] += d; 
            state[4] += e;
            state[5] += f; 
            state[6] += g;
            state[7] += h;
        }
 
        private static UInt32 RotateRight(UInt32 x, int n) {
            return (((x) >> (n)) | ((x) << (32-(n)))); 
        } 

        private static UInt32 Ch(UInt32 x, UInt32 y, UInt32 z) { 
            return ((x & y) ^ ((x ^ 0xffffffff) & z));
        }

        private static UInt32 Maj(UInt32 x, UInt32 y, UInt32 z) { 
            return ((x & y) ^ (x & z) ^ (y & z));
        } 
 
        private static UInt32 sigma_0(UInt32 x) {
            return (RotateRight(x,7) ^ RotateRight(x,18) ^ (x >> 3)); 
        }

        private static UInt32 sigma_1(UInt32 x) {
            return (RotateRight(x,17) ^ RotateRight(x,19) ^ (x >> 10)); 
        }
 
        private static UInt32 Sigma_0(UInt32 x) { 
            return (RotateRight(x,2) ^ RotateRight(x,13) ^ RotateRight(x,22));
        } 

        private static UInt32 Sigma_1(UInt32 x) {
            return (RotateRight(x,6) ^ RotateRight(x,11) ^ RotateRight(x,25));
        } 

        /* This function creates W_16,...,W_63 according to the formula 
           W_j <- sigma_1(W_{j-2}) + W_{j-7} + sigma_0(W_{j-15}) + W_{j-16}; 
        */
 
        [System.Security.SecurityCritical]  // auto-generated
        private static unsafe void SHA256Expand (uint* x)
        {
            for (int i = 16; i < 64; i++) { 
                x[i] = sigma_1(x[i-2]) + x[i-7] + sigma_0(x[i-15]) + x[i-16];
            } 
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
// [....]
// 
 
//
// SHA256Managed.cs 
//
// C# implementation of the proposed SHA-256 hash algorithm
//
 
namespace System.Security.Cryptography {
    using System; 
    using System.Security; 
    using System.Diagnostics.Contracts;
 
    [System.Runtime.InteropServices.ComVisible(true)]
    public class SHA256Managed : SHA256
    {
        private byte[]   _buffer; 
        private long     _count; // Number of bytes in the hashed message
        private UInt32[] _stateSHA256; 
        private UInt32[] _W; 

        // 
        // public constructors
        //

        public SHA256Managed() 
        {
#if FEATURE_CRYPTO 
            if (CryptoConfig.AllowOnlyFipsAlgorithms) 
                throw new InvalidOperationException(Environment.GetResourceString("Cryptography_NonCompliantFIPSAlgorithm"));
            Contract.EndContractBlock(); 
#endif // FEATURE_CRYPTO

            _stateSHA256 = new UInt32[8];
            _buffer = new byte[64]; 
            _W = new UInt32[64];
 
            InitializeState(); 
        }
 
        //
        // public methods
        //
 
        public override void Initialize() {
            InitializeState(); 
 
            // Zeroize potentially sensitive information.
            Array.Clear(_buffer, 0, _buffer.Length); 
            Array.Clear(_W, 0, _W.Length);
        }

        protected override void HashCore(byte[] rgb, int ibStart, int cbSize) { 
            _HashData(rgb, ibStart, cbSize);
        } 
 
        protected override byte[] HashFinal() {
            return _EndHash(); 
        }

        //
        // private methods 
        //
 
        private void InitializeState() { 
            _count = 0;
 
            _stateSHA256[0] = 0x6a09e667;
            _stateSHA256[1] = 0xbb67ae85;
            _stateSHA256[2] = 0x3c6ef372;
            _stateSHA256[3] = 0xa54ff53a; 
            _stateSHA256[4] = 0x510e527f;
            _stateSHA256[5] = 0x9b05688c; 
            _stateSHA256[6] = 0x1f83d9ab; 
            _stateSHA256[7] = 0x5be0cd19;
        } 

        /* SHA256 block update operation. Continues an SHA message-digest
           operation, processing another message block, and updating the
           context. 
           */
 
        [System.Security.SecuritySafeCritical]  // auto-generated 
        private unsafe void _HashData(byte[] partIn, int ibStart, int cbSize)
        { 
            int bufferLen;
            int partInLen = cbSize;
            int partInBase = ibStart;
 
            /* Compute length of buffer */
            bufferLen = (int) (_count & 0x3f); 
 
            /* Update number of bytes */
            _count += partInLen; 

            fixed (uint* stateSHA256 = _stateSHA256) {
                fixed (byte* buffer = _buffer) {
                    fixed (uint* expandedBuffer = _W) { 
                        if ((bufferLen > 0) && (bufferLen + partInLen >= 64)) {
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, bufferLen, 64 - bufferLen); 
                            partInBase += (64 - bufferLen); 
                            partInLen -= (64 - bufferLen);
                            SHATransform(expandedBuffer, stateSHA256, buffer); 
                            bufferLen = 0;
                        }

                        /* Copy input to temporary buffer and hash */ 
                        while (partInLen >= 64) {
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, 0, 64); 
                            partInBase += 64; 
                            partInLen -= 64;
                            SHATransform(expandedBuffer, stateSHA256, buffer); 
                        }

                        if (partInLen > 0) {
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, bufferLen, partInLen); 
                        }
                    } 
                } 
            }
        } 

        /* SHA256 finalization. Ends an SHA256 message-digest operation, writing
           the message digest.
           */ 

        private byte[] _EndHash() 
        { 
            byte[]         pad;
            int            padLen; 
            long           bitCount;
            byte[]         hash = new byte[32]; // HashSizeValue = 256

            /* Compute padding: 80 00 00 ... 00 00  
             */
 
            padLen = 64 - (int)(_count & 0x3f); 
            if (padLen <= 8)
                padLen += 64; 

            pad = new byte[padLen];
            pad[0] = 0x80;
 
            //  Convert count to bit count
            bitCount = _count * 8; 
 
            pad[padLen-8] = (byte) ((bitCount >> 56) & 0xff);
            pad[padLen-7] = (byte) ((bitCount >> 48) & 0xff); 
            pad[padLen-6] = (byte) ((bitCount >> 40) & 0xff);
            pad[padLen-5] = (byte) ((bitCount >> 32) & 0xff);
            pad[padLen-4] = (byte) ((bitCount >> 24) & 0xff);
            pad[padLen-3] = (byte) ((bitCount >> 16) & 0xff); 
            pad[padLen-2] = (byte) ((bitCount >> 8) & 0xff);
            pad[padLen-1] = (byte) ((bitCount >> 0) & 0xff); 
 
            /* Digest padding */
            _HashData(pad, 0, pad.Length); 

            /* Store digest */
            Utils.DWORDToBigEndian (hash, _stateSHA256, 8);
 
            HashValue = hash;
            return hash; 
        } 

        private readonly static UInt32[] _K = { 
            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
            0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
            0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 
            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
            0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 
            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 
            0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 
            0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
            0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
            0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 
            0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 
            0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2 
        };
 
        [System.Security.SecurityCritical]  // auto-generated
        private static unsafe void SHATransform (uint* expandedBuffer, uint* state, byte* block)
        {
            UInt32 a, b, c, d, e, f, h, g; 
            UInt32 aa, bb, cc, dd, ee, ff, hh, gg;
            UInt32 T1; 
 
            a = state[0];
            b = state[1]; 
            c = state[2];
            d = state[3];
            e = state[4];
            f = state[5]; 
            g = state[6];
            h = state[7]; 
 
            // fill in the first 16 bytes of W.
            Utils.DWORDFromBigEndian(expandedBuffer, 16, block); 
            SHA256Expand(expandedBuffer);

            /* Apply the SHA256 compression function */
            // We are trying to be smart here and avoid as many copies as we can 
            // The perf gain with this method over the straightforward modify and shift
            // forward is >= 20%, so it's worth the pain 
            for (int j=0; j<64; ) { 
                T1 = h + Sigma_1(e) + Ch(e,f,g) + _K[j] + expandedBuffer[j];
                ee = d + T1; 
                aa = T1 + Sigma_0(a) + Maj(a,b,c);
                j++;

                T1 = g + Sigma_1(ee) + Ch(ee,e,f) + _K[j] + expandedBuffer[j]; 
                ff = c + T1;
                bb = T1 + Sigma_0(aa) + Maj(aa,a,b); 
                j++; 

                T1 = f + Sigma_1(ff) + Ch(ff,ee,e) + _K[j] + expandedBuffer[j]; 
                gg = b + T1;
                cc = T1 + Sigma_0(bb) + Maj(bb,aa,a);
                j++;
 
                T1 = e + Sigma_1(gg) + Ch(gg,ff,ee) + _K[j] + expandedBuffer[j];
                hh = a + T1; 
                dd = T1 + Sigma_0(cc) + Maj(cc,bb,aa); 
                j++;
 
                T1 = ee + Sigma_1(hh) + Ch(hh,gg,ff) + _K[j] + expandedBuffer[j];
                h = aa + T1;
                d = T1 + Sigma_0(dd) + Maj(dd,cc,bb);
                j++; 

                T1 = ff + Sigma_1(h) + Ch(h,hh,gg) + _K[j] + expandedBuffer[j]; 
                g = bb + T1; 
                c = T1 + Sigma_0(d) + Maj(d,dd,cc);
                j++; 

                T1 = gg + Sigma_1(g) + Ch(g,h,hh) + _K[j] + expandedBuffer[j];
                f = cc + T1;
                b = T1 + Sigma_0(c) + Maj(c,d,dd); 
                j++;
 
                T1 = hh + Sigma_1(f) + Ch(f,g,h) + _K[j] + expandedBuffer[j]; 
                e = dd + T1;
                a = T1 + Sigma_0(b) + Maj(b,c,d); 
                j++;
            }

            state[0] += a; 
            state[1] += b;
            state[2] += c; 
            state[3] += d; 
            state[4] += e;
            state[5] += f; 
            state[6] += g;
            state[7] += h;
        }
 
        private static UInt32 RotateRight(UInt32 x, int n) {
            return (((x) >> (n)) | ((x) << (32-(n)))); 
        } 

        private static UInt32 Ch(UInt32 x, UInt32 y, UInt32 z) { 
            return ((x & y) ^ ((x ^ 0xffffffff) & z));
        }

        private static UInt32 Maj(UInt32 x, UInt32 y, UInt32 z) { 
            return ((x & y) ^ (x & z) ^ (y & z));
        } 
 
        private static UInt32 sigma_0(UInt32 x) {
            return (RotateRight(x,7) ^ RotateRight(x,18) ^ (x >> 3)); 
        }

        private static UInt32 sigma_1(UInt32 x) {
            return (RotateRight(x,17) ^ RotateRight(x,19) ^ (x >> 10)); 
        }
 
        private static UInt32 Sigma_0(UInt32 x) { 
            return (RotateRight(x,2) ^ RotateRight(x,13) ^ RotateRight(x,22));
        } 

        private static UInt32 Sigma_1(UInt32 x) {
            return (RotateRight(x,6) ^ RotateRight(x,11) ^ RotateRight(x,25));
        } 

        /* This function creates W_16,...,W_63 according to the formula 
           W_j <- sigma_1(W_{j-2}) + W_{j-7} + sigma_0(W_{j-15}) + W_{j-16}; 
        */
 
        [System.Security.SecurityCritical]  // auto-generated
        private static unsafe void SHA256Expand (uint* x)
        {
            for (int i = 16; i < 64; i++) { 
                x[i] = sigma_1(x[i-2]) + x[i-7] + sigma_0(x[i-15]) + x[i-16];
            } 
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
                        

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