SHA1Managed.cs source code in C# .NET

Source code for the .NET framework in C#

                        

Code:

/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / SHA1Managed.cs / 1 / SHA1Managed.cs

                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

// 
// SHA1Managed.cs 
//
 
namespace System.Security.Cryptography {
    using System;

    [System.Runtime.InteropServices.ComVisible(true)] 
    public class SHA1Managed : SHA1
    { 
        private byte[] _buffer; 
        private long   _count; // Number of bytes in the hashed message
        private uint[] _stateSHA1; 
        private uint[] _expandedBuffer;

        //
        // public constructors 
        //
 
        public SHA1Managed() 
        {
            if (Utils.FipsAlgorithmPolicy == 1) 
                throw new InvalidOperationException(Environment.GetResourceString("Cryptography_NonCompliantFIPSAlgorithm"));

            _stateSHA1 = new uint[5];
            _buffer = new byte[64]; 
            _expandedBuffer = new uint[80];
 
            InitializeState(); 
        }
 
        //
        // public methods
        //
 
        public override void Initialize() {
            InitializeState(); 
 
            // Zeroize potentially sensitive information.
            Array.Clear(_buffer, 0, _buffer.Length); 
            Array.Clear(_expandedBuffer, 0, _expandedBuffer.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;
 
            _stateSHA1[0] =  0x67452301;
            _stateSHA1[1] =  0xefcdab89;
            _stateSHA1[2] =  0x98badcfe;
            _stateSHA1[3] =  0x10325476; 
            _stateSHA1[4] =  0xc3d2e1f0;
        } 
 
        /* Copyright (C) RSA Data Security, Inc. created 1993.  This is an
           unpublished work protected as such under copyright law.  This work 
           contains proprietary, confidential, and trade secret information of
           RSA Data Security, Inc.  Use, disclosure or reproduction without the
           express written authorization of RSA Data Security, Inc. is
           prohibited. 
           */
 
        /* SHA block update operation. Continues an SHA message-digest 
           operation, processing another message block, and updating the
           context. 
           */

        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* stateSHA1 = _stateSHA1) { 
                fixed (byte* buffer = _buffer) { 
                    fixed (uint* expandedBuffer = _expandedBuffer) {
                        if ((bufferLen > 0) && (bufferLen + partInLen >= 64)) { 
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, bufferLen, 64 - bufferLen);
                            partInBase += (64 - bufferLen);
                            partInLen -= (64 - bufferLen);
                            SHATransform(expandedBuffer, stateSHA1, 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, stateSHA1, buffer); 
                        }
 
                        if (partInLen > 0) { 
                            Buffer.InternalBlockCopy(partIn, partInBase, _buffer, bufferLen, partInLen);
                        } 
                    }
                }
            }
        } 

        /* SHA finalization. Ends an SHA message-digest operation, writing 
           the message digest. 
            */
 
        private byte[] _EndHash()
        {
            byte[]          pad;
            int             padLen; 
            long            bitCount;
            byte[]          hash = new byte[20]; 
 
            /* 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, _stateSHA1, 5); 

            HashValue = hash; 
            return hash;
        }

        private static unsafe void SHATransform (uint* expandedBuffer, uint* state, byte* block) 
        {
            uint a = state[0]; 
            uint b = state[1]; 
            uint c = state[2];
            uint d = state[3]; 
            uint e = state[4];

            int i;
 
            Utils.DWORDFromBigEndian(expandedBuffer, 16, block);
            SHAExpand(expandedBuffer); 
 
            /* Round 1 */
            for (i=0; i<20; i+= 5) { 
                { (e) +=  (((((a)) << (5)) | (((a)) >> (32-(5)))) + ( (d) ^ ( (b) & ( (c) ^ (d) ) ) ) + (expandedBuffer[i]) + 0x5a827999); (b) =  ((((b)) << (30)) | (((b)) >> (32-(30)))); }
                { (d) +=  (((((e)) << (5)) | (((e)) >> (32-(5)))) + ( (c) ^ ( (a) & ( (b) ^ (c) ) ) ) + (expandedBuffer[i+1]) + 0x5a827999); (a) =  ((((a)) << (30)) | (((a)) >> (32-(30)))); }
                { (c) +=  (((((d)) << (5)) | (((d)) >> (32-(5)))) + ( (b) ^ ( (e) & ( (a) ^ (b) ) ) ) + (expandedBuffer[i+2]) + 0x5a827999); (e) =  ((((e)) << (30)) | (((e)) >> (32-(30)))); };;
                { (b) +=  (((((c)) << (5)) | (((c)) >> (32-(5)))) + ( (a) ^ ( (d) & ( (e) ^ (a) ) ) ) + (expandedBuffer[i+3]) + 0x5a827999); (d) =  ((((d)) << (30)) | (((d)) >> (32-(30)))); };; 
                { (a) +=  (((((b)) << (5)) | (((b)) >> (32-(5)))) + ( (e) ^ ( (c) & ( (d) ^ (e) ) ) ) + (expandedBuffer[i+4]) + 0x5a827999); (c) =  ((((c)) << (30)) | (((c)) >> (32-(30)))); };;
            } 
 
            /* Round 2 */
            for (; i<40; i+= 5) { 
                { (e) +=  (((((a)) << (5)) | (((a)) >> (32-(5)))) + ((b) ^ (c) ^ (d)) + (expandedBuffer[i]) + 0x6ed9eba1); (b) =  ((((b)) << (30)) | (((b)) >> (32-(30)))); };;
                { (d) +=  (((((e)) << (5)) | (((e)) >> (32-(5)))) + ((a) ^ (b) ^ (c)) + (expandedBuffer[i+1]) + 0x6ed9eba1); (a) =  ((((a)) << (30)) | (((a)) >> (32-(30)))); };;
                { (c) +=  (((((d)) << (5)) | (((d)) >> (32-(5)))) + ((e) ^ (a) ^ (b)) + (expandedBuffer[i+2]) + 0x6ed9eba1); (e) =  ((((e)) << (30)) | (((e)) >> (32-(30)))); };;
                { (b) +=  (((((c)) << (5)) | (((c)) >> (32-(5)))) + ((d) ^ (e) ^ (a)) + (expandedBuffer[i+3]) + 0x6ed9eba1); (d) =  ((((d)) << (30)) | (((d)) >> (32-(30)))); };; 
                { (a) +=  (((((b)) << (5)) | (((b)) >> (32-(5)))) + ((c) ^ (d) ^ (e)) + (expandedBuffer[i+4]) + 0x6ed9eba1); (c) =  ((((c)) << (30)) | (((c)) >> (32-(30)))); };;
            } 
 
            /* Round 3 */
            for (; i<60; i+=5) { 
                { (e) +=  (((((a)) << (5)) | (((a)) >> (32-(5)))) + ( ( (b) & (c) ) | ( (d) & ( (b) | (c) ) ) ) + (expandedBuffer[i]) + 0x8f1bbcdc); (b) =  ((((b)) << (30)) | (((b)) >> (32-(30)))); };;
                { (d) +=  (((((e)) << (5)) | (((e)) >> (32-(5)))) + ( ( (a) & (b) ) | ( (c) & ( (a) | (b) ) ) ) + (expandedBuffer[i+1]) + 0x8f1bbcdc); (a) =  ((((a)) << (30)) | (((a)) >> (32-(30)))); };;
                { (c) +=  (((((d)) << (5)) | (((d)) >> (32-(5)))) + ( ( (e) & (a) ) | ( (b) & ( (e) | (a) ) ) ) + (expandedBuffer[i+2]) + 0x8f1bbcdc); (e) =  ((((e)) << (30)) | (((e)) >> (32-(30)))); };;
                { (b) +=  (((((c)) << (5)) | (((c)) >> (32-(5)))) + ( ( (d) & (e) ) | ( (a) & ( (d) | (e) ) ) ) + (expandedBuffer[i+3]) + 0x8f1bbcdc); (d) =  ((((d)) << (30)) | (((d)) >> (32-(30)))); };; 
                { (a) +=  (((((b)) << (5)) | (((b)) >> (32-(5)))) + ( ( (c) & (d) ) | ( (e) & ( (c) | (d) ) ) ) + (expandedBuffer[i+4]) + 0x8f1bbcdc); (c) =  ((((c)) << (30)) | (((c)) >> (32-(30)))); };;
            } 
 
            /* Round 4 */
            for (; i<80; i+=5) { 
                { (e) +=  (((((a)) << (5)) | (((a)) >> (32-(5)))) + ((b) ^ (c) ^ (d)) + (expandedBuffer[i]) + 0xca62c1d6); (b) =  ((((b)) << (30)) | (((b)) >> (32-(30)))); };;
                { (d) +=  (((((e)) << (5)) | (((e)) >> (32-(5)))) + ((a) ^ (b) ^ (c)) + (expandedBuffer[i+1]) + 0xca62c1d6); (a) =  ((((a)) << (30)) | (((a)) >> (32-(30)))); };;
                { (c) +=  (((((d)) << (5)) | (((d)) >> (32-(5)))) + ((e) ^ (a) ^ (b)) + (expandedBuffer[i+2]) + 0xca62c1d6); (e) =  ((((e)) << (30)) | (((e)) >> (32-(30)))); };;
                { (b) +=  (((((c)) << (5)) | (((c)) >> (32-(5)))) + ((d) ^ (e) ^ (a)) + (expandedBuffer[i+3]) + 0xca62c1d6); (d) =  ((((d)) << (30)) | (((d)) >> (32-(30)))); };; 
                { (a) +=  (((((b)) << (5)) | (((b)) >> (32-(5)))) + ((c) ^ (d) ^ (e)) + (expandedBuffer[i+4]) + 0xca62c1d6); (c) =  ((((c)) << (30)) | (((c)) >> (32-(30)))); };;
            } 
 
            state[0] += a;
            state[1] += b; 
            state[2] += c;
            state[3] += d;
            state[4] += e;
        } 

        /* Expands x[0..15] into x[16..79], according to the recurrence 
           x[i] = x[i-3] ^ x[i-8] ^ x[i-14] ^ x[i-16]. 
           */
 
        private static unsafe void SHAExpand (uint* x)
        {
            int  i;
            uint tmp; 

            for (i = 16; i < 80; i++) { 
                tmp =  (x[i-3] ^ x[i-8] ^ x[i-14] ^ x[i-16]); 
                x[i] =  ((tmp << 1) | (tmp >> 31));
            } 
        }
    }
}
                        

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