// MD5.CPP - RSA Data Security, Inc., MD5 message-digest algorithm

/*
Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
rights reserved.

License to copy and use this software is granted provided that it
is identified as the "RSA Data Security, Inc. MD5 Message-Digest
Algorithm" in all material mentioning or referencing this software
or this function.

License is also granted to make and use derivative works provided
that such works are identified as "derived from the RSA Data
Security, Inc. MD5 Message-Digest Algorithm" in all material
mentioning or referencing the derived work.

RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.

These notices must be retained in any copies of any part of this
documentation and/or software.
*/

//#include <assert.h>
#include <memory.h>
#include <ctype.h>
#include <vector>
#include "MD5.h"

using std::string;
using std::vector;

// Constants for MD5Transform routine.
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

static void MD5Transform ( UINT4 [4], const uchar [64] );
static void Encode ( unsigned char *, UINT4 *, unsigned int );
static void Decode ( UINT4 *, const uchar *, unsigned int );

static unsigned char PADDING[64] =
{
	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

// F, G, H and I are basic MD5 functions.
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

// ROTATE_LEFT rotates x left n bits.
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

// FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
// Rotation is separate from addition to prevent recomputation.
#define FF(a, b, c, d, x, s, ac) { \
	(a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define GG(a, b, c, d, x, s, ac) { \
	(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define HH(a, b, c, d, x, s, ac) { \
	(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}
#define II(a, b, c, d, x, s, ac) { \
	(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
	(a) = ROTATE_LEFT ((a), (s)); \
	(a) += (b); \
	}

// MD5 initialization. Begins an MD5 operation, writing a new context.
void MD5Init (
	MD5_CTX *context ) // context
{
	context->count[0] = context->count[1] = 0;
	// Load magic initialization constants.
	context->state[0] = 0x67452301;
	context->state[1] = 0xefcdab89;
	context->state[2] = 0x98badcfe;
	context->state[3] = 0x10325476;
}

// MD5 block update operation. Continues an MD5 message-digest
// operation, processing another message block, and updating the
// context.
void MD5Update (
	MD5_CTX *context,       // context
	const char *input_,     // input block
	unsigned int inputLen ) // length of input block
{
	unsigned int i, index, partLen;
	const uchar* input = (const uchar*)input_;

	// Compute number of bytes mod 64
	index = (unsigned int)((context->count[0] >> 3) & 0x3F);

	// Update number of bits
	if ((context->count[0] += ((UINT4)inputLen << 3))
		< ((UINT4)inputLen << 3))
		context->count[1]++;
	context->count[1] += ((UINT4)inputLen >> 29);

	partLen = 64 - index;

	// Transform as many times as possible.
	if (inputLen >= partLen)
	{
		memcpy
			((POINTER)&context->buffer[index], (POINTER)input, partLen);
		MD5Transform (context->state, context->buffer);

		for (i = partLen; i + 63 < inputLen; i += 64)
			MD5Transform (context->state, &input[i]);

		index = 0;
	}
	else
		i = 0;

	// Buffer remaining input
	memcpy
		((POINTER)&context->buffer[index], (POINTER)&input[i],
		inputLen-i);
}

// MD5 finalization. Ends an MD5 message-digest operation, writing the
// the message digest and zeroizing the context.
void MD5Final (
	unsigned char digest[16], // message digest
	MD5_CTX *context )        // context
{
	uchar bits[8];
	unsigned int index, padLen;

	// Save number of bits
	Encode (bits, context->count, 8);

	// Pad out to 56 mod 64.
	index = (unsigned int)((context->count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	MD5Update (context, (const char*)PADDING, padLen);

	// Append length (before padding)
	MD5Update (context, (const char*)bits, 8);

	// Store state in digest
	Encode (digest, context->state, 16);

	// Zeroize sensitive information.
	memset ((POINTER)context, 0, sizeof (*context));
}

// MD5 basic transformation. Transforms state based on block.
static void MD5Transform (
	UINT4 state[4],
	const uchar block[64] )
{
	UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];

	Decode (x, block, 64);

	// Round 1
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); // 1
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); // 2
	FF (c, d, a, b, x[ 2], S13, 0x242070db); // 3
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); // 4
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); // 5
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); // 6
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); // 7
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); // 8
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); // 9
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); // 10
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); // 11
	FF (b, c, d, a, x[11], S14, 0x895cd7be); // 12
	FF (a, b, c, d, x[12], S11, 0x6b901122); // 13
	FF (d, a, b, c, x[13], S12, 0xfd987193); // 14
	FF (c, d, a, b, x[14], S13, 0xa679438e); // 15
	FF (b, c, d, a, x[15], S14, 0x49b40821); // 16

	// Round 2
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); // 17
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); // 18
	GG (c, d, a, b, x[11], S23, 0x265e5a51); // 19
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); // 20
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); // 21
	GG (d, a, b, c, x[10], S22,  0x2441453); // 22
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); // 23
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); // 24
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); // 25
	GG (d, a, b, c, x[14], S22, 0xc33707d6); // 26
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); // 27
	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); // 28
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); // 29
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); // 30
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); // 31
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); // 32

	// Round 3
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); // 33
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); // 34
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); // 35
	HH (b, c, d, a, x[14], S34, 0xfde5380c); // 36
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); // 37
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); // 38
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); // 39
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); // 40
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); // 41
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); // 42
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); // 43
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); // 44
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); // 45
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); // 46
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); // 47
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); // 48

	// Round 4
	II (a, b, c, d, x[ 0], S41, 0xf4292244); // 49
	II (d, a, b, c, x[ 7], S42, 0x432aff97); // 50
	II (c, d, a, b, x[14], S43, 0xab9423a7); // 51
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); // 52
	II (a, b, c, d, x[12], S41, 0x655b59c3); // 53
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); // 54
	II (c, d, a, b, x[10], S43, 0xffeff47d); // 55
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); // 56
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); // 57
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); // 58
	II (c, d, a, b, x[ 6], S43, 0xa3014314); // 59
	II (b, c, d, a, x[13], S44, 0x4e0811a1); // 60
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); // 61
	II (d, a, b, c, x[11], S42, 0xbd3af235); // 62
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); // 63
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); // 64

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

	// Zeroize sensitive information.
	memset ((POINTER)x, 0, sizeof (x));
}

// Encodes input (UINT4) into output (unsigned char). Assumes len is
// a multiple of 4.
static void Encode (
	unsigned char *output,
	UINT4 *input,
	unsigned int len )
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4) {
		output[j] = (unsigned char)(input[i] & 0xff);
		output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
		output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
		output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
	}
}

// Decodes input (unsigned char) into output (UINT4). Assumes len is
// a multiple of 4.
static void Decode (
	UINT4 *output,
	const uchar *input,
	unsigned int len )
{
	unsigned int i, j;

	for (i = 0, j = 0; j < len; i++, j += 4)
		output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
		(((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
}

void digest2ascii ( char *ascii, const unsigned char *digest )
{
	int i;
	static char* table = "0123456789abcdef";
	for ( i = 0; i < 16; i++ )
	{
		*ascii++ = table[(*digest)>>4];
		*ascii++ = table[(*digest++)%16];
	}
	*ascii++ = 0;
}

void ascii2digest ( unsigned char *digest, const char *ascii )
{
	int i;
#define CONV(c) (unsigned char)( (toupper(c)>='A') ? (toupper(c)+10-'A') : ((c)-'0') )
#define MAKECHAR(a,b) ((CONV(a)%16)<<4)|(CONV(b)%16)
	for ( i = 0; i < 16; i++ )
	{
		*digest++ = MAKECHAR(ascii[0],ascii[1]);
		ascii += 2;
	}
}

#ifdef __cplusplus
MD5::MD5()
{
	Init();
}

void MD5::Init()
{
	MD5Init(&_ctx);
}

void MD5::Update ( const string& s )
{
	MD5Update ( &_ctx, s.c_str(), s.size() );
}

string MD5::Final ( char* digest )
{
	vector<uchar> v;
	v.resize(16);
	MD5Final ( &v[0], &_ctx );
	if ( digest )
		memmove ( digest, &v[0], 16 );
	string s;
	static char* tohex = "0123456789abcdef";
	for ( int i = 0; i < 16; i++ )
	{
		uchar c = v[i];
		s += tohex[ (c>>4) & 0xF ];
		s += tohex[ c & 0xF ];
	}
	return s;
}

string MD5Hex ( const string& s )
{
	MD5 md5;
	md5.Update ( s );
	return md5.Final();
}

string MD5Bin ( const string& s )
{
	MD5 md5;
	md5.Update ( s );
	char digest[16];
	md5.Final ( digest );
	return string ( digest, 16 );
}

string HMAC_MD5 ( const string& key, const string& text, char* out_bin )
{
	MD5 md5;
	char k_ipad[65]; // inner padding - key XORd with ipad
	char k_opad[65]; // outer padding - key XORd with opad
	string tmp;
	char digest[16];
	int i;
	// if key is longer than 64 bytes reset it to key=MD5(key)
	if ( key.length() > 64 )
	{
		md5.Init();
		md5.Update ( key );
		md5.Final ( digest );
		tmp = string ( digest, 16 );
	}
	else
		tmp = key;

	// start out by storing key in pads
	memset ( k_ipad, 0, sizeof(k_ipad) );
	memset ( k_opad, 0, sizeof(k_opad) );
	memcpy ( k_ipad, tmp.c_str(), tmp.length() );
	memcpy ( k_opad, tmp.c_str(), tmp.length() );

	// XOR key with ipad and opad values
	for ( i=0; i<64; i++ )
	{
		k_ipad[i] ^= 0x36;
		k_opad[i] ^= 0x5c;
	}

	// "inner" MD5
	md5.Init();
	md5.Update(k_ipad);
	md5.Update(text);
	md5.Final ( digest );

	// "outer" MD5
	md5.Init();
	md5.Update(k_opad);
	md5.Update(string(digest,16));
	return md5.Final(out_bin);
}
#endif//__cplusplus