MD5Hash.cpp

Idź do dokumentacji tego pliku.

/****************************************************************************
** Filename: MD5Hash.cpp
** Last updated [dd/mm/yyyy]: 01/10/2005
**
** Computes MD5 hash of a file or buffer [Requires Qt4 - QtCore module].
**
** The MD5 algorithm was written by Ron Rivest.
** This class is based on the code written by Colin Plumb in 1993,
** our understanding is that no copyright is claimed and that this code is in
** the public domain.
**
** NO WARRANTY is given for this code.
** Use it at your own risk.
** It should produce correct SHA1 digests, but no security-related test has been made.
**
** Copyright (C) 2005 Angius Fabrizio. All rights reserved.
**
** This file is part of the OSDaB project (http://osdab.sourceforge.net/).
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See the file LICENSE.GPL that came with this software distribution or
** visit http://www.gnu.org/copyleft/gpl.html for GPL licensing information.
**
**********************************************************************/

#include <MD5Hash.h>

#include <QtCore/QFile>
#include <QtCore/QByteArray>
#include <QtCore/QBitArray>

// 512K buffer
#define MD5_READ_BUFFER 524288



QString MD5Hash::hashData(const char* bytes, int size)
{
        /*
         * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
         * initialization constants.
         */

        md5Context ctx;

        ctx.buffer[0] = 0x67452301;
        ctx.buffer[1] = 0xefcdab89;
        ctx.buffer[2] = 0x98badcfe;
        ctx.buffer[3] = 0x10325476;

        ctx.bits[0] = 0;
        ctx.bits[1] = 0;

        updateHash(&ctx, bytes, size);

        return finalize(ctx);
}

QString MD5Hash::hashData(const QByteArray& bytes)
{
        return hashData(bytes.data(), bytes.size());
}

QString MD5Hash::hashFile(QFile& file)
{
        /* To compute the message digest of a chunk of bytes, declare an
         * MD5Context structure, pass it to MD5Init, call MD5Update as
         * needed on buffers full of bytes, and then call MD5Final, which
         * will fill a supplied 16-byte array with the digest.
         */

        if (!file.open(QIODevice::ReadOnly))
                return QString();

        /*
         * Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
         * initialization constants.
         */

        md5Context ctx;

        ctx.buffer[0] = 0x67452301;
        ctx.buffer[1] = 0xefcdab89;
        ctx.buffer[2] = 0x98badcfe;
        ctx.buffer[3] = 0x10325476;

        ctx.bits[0] = 0;
        ctx.bits[1] = 0;

        long int read;
        QByteArray buffer(MD5_READ_BUFFER, 0);
        char* data = buffer.data();

        while ( (read = file.read(data, MD5_READ_BUFFER)) > 0 )
                updateHash(&ctx, data, read);

        if (read < 0)
                return QString();

        return finalize(ctx);
}

QString MD5Hash::hashFile(const QString& filename)
{
        QFile file(filename);
        return hashFile(file);
}

void MD5Hash::updateHash(md5Context* ctx, const char* data, long int length)
{
        unsigned int t;

        // Update bitcount
        t = ctx->bits[0];
        if ((ctx->bits[0] = t + ((unsigned int) length << 3)) < t)
                ctx->bits[1]++; // Carry from low to high
        ctx->bits[1] += length >> 29;

        t = (t >> 3) & 0x3f; // buffer index

        // Handle any leading odd-sized chunks
        if (t)
        {
                unsigned char *p = (unsigned char *) ctx->in + t;

                t = 64 - t;

                if ((unsigned long int)length < t)
                {
                        memcpy(p, data, length);
                        return;
                }

                memcpy(p, data, t);
                md5Transform(ctx->buffer, (unsigned int *) ctx->in);
                data += t;
                length -= t;
        }

        // Process data in 64-byte chunks
        while (length >= 64)
        {
                memcpy(ctx->in, data, 64);
                md5Transform(ctx->buffer, (unsigned int *) ctx->in);
                data += 64;
                length -= 64;
        }

        // Handle any remaining bytes of data.
        memcpy(ctx->in, data, length);
}

QString MD5Hash::finalize(md5Context& ctx)
{
        unsigned count;
        unsigned char *p;

        // Compute number of bytes mod 64
        count = (ctx.bits[0] >> 3) & 0x3F;

        // Set the first char of padding to 0x80.
        // This is safe since there is always at least one byte free
        p = ctx.in + count;
        *p++ = 0x80;

        // Bytes of padding needed to make 64 bytes
        count = 64 - 1 - count;

        // Pad out to 56 mod 64
        if (count < 8)
        {
                // Two lots of padding:  Pad the first block to 64 bytes
                memset(p, 0, count);
                md5Transform(ctx.buffer, (unsigned int *) ctx.in);

                // Now fill the next block with 56 bytes
                memset(ctx.in, 0, 56);
        }
        else
        {
                // Pad block to 56 bytes
                memset(p, 0, count - 8);
        }

        // Append length in bits and transform
        ((unsigned int *) ctx.in)[14] = ctx.bits[0];
        ((unsigned int *) ctx.in)[15] = ctx.bits[1];

        md5Transform(ctx.buffer, (unsigned int *) ctx.in);

        // You may need to wipe variables for security reasons before returning!!!

        QString digest;
        digest.sprintf("%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
                (ctx.buffer[0])&0xFF, (ctx.buffer[0]>>8)&0xFF, (ctx.buffer[0]>>16)&0xFF, (ctx.buffer[0]>>24)&0xFF,
                (ctx.buffer[1])&0xFF, (ctx.buffer[1]>>8)&0xFF, (ctx.buffer[1]>>16)&0xFF, (ctx.buffer[1]>>24)&0xFF,
                (ctx.buffer[2])&0xFF, (ctx.buffer[2]>>8)&0xFF, (ctx.buffer[2]>>16)&0xFF, (ctx.buffer[2]>>24)&0xFF,
                (ctx.buffer[3])&0xFF, (ctx.buffer[3]>>8)&0xFF, (ctx.buffer[3]>>16)&0xFF, (ctx.buffer[3]>>24)&0xFF
                );
        
        return digest;
}

// ************ CORE FUNCTIONS *******************************************

// #define F1(x, y, z) (x & y | ~x & z)
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

// This is the central step in the MD5 algorithm.
#define MD5STEP(f, w, x, y, z, data, s) \
        ( w += f(x, y, z) + data,  w = w<<s | w>>(32-s),  w += x )

/*
 * The core of the MD5 algorithm, this alters an existing MD5 hash to
 * reflect the addition of 16 longwords of new data. MD5Update blocks
 * the data and converts bytes into longwords for this routine.
 */
void MD5Hash::md5Transform(unsigned int buf[4], unsigned int const in[16])
{
        register unsigned int a, b, c, d;

        a = buf[0];
        b = buf[1];
        c = buf[2];
        d = buf[3];

        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

        buf[0] += a;
        buf[1] += b;
        buf[2] += c;
        buf[3] += d;
}

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