/* SHA256 module */

/* This module provides an interface to NIST's SHA-256 and SHA-224 Algorithms */

/* See below for information about the original code this module was

   based upon. Additional work performed by:

   Andrew Kuchling (amk@amk.ca)

   Greg Stein (gstein@lyra.org)

   Trevor Perrin (trevp@trevp.net)

   Copyright (C) 2005   Gregory P. Smith (greg@krypto.org)

   Licensed to PSF under a Contributor Agreement.

*/

/* SHA objects */

#include "Python.h"

#include "structmember.h"

/* Endianness testing and definitions */

#define TestEndianness(variable) {int i=1; variable=PCT_BIG_ENDIAN;\

	if (*((char*)&i)==1) variable=PCT_LITTLE_ENDIAN;}

#define PCT_LITTLE_ENDIAN 1

#define PCT_BIG_ENDIAN 0

/* Some useful types */

typedef unsigned char SHA_BYTE;

#if SIZEOF_INT == 4

typedef unsigned int SHA_INT32;	/* 32-bit integer */

#else

/* not defined. compilation will die. */

#endif

/* The SHA block size and message digest sizes, in bytes */

#define SHA_BLOCKSIZE    64

#define SHA_DIGESTSIZE  32

/* The structure for storing SHA info */

typedef struct {

    PyObject_HEAD

    SHA_INT32 digest[8];		/* Message digest */

    SHA_INT32 count_lo, count_hi;	/* 64-bit bit count */

    SHA_BYTE data[SHA_BLOCKSIZE];	/* SHA data buffer */

    int Endianness;

    int local;				/* unprocessed amount in data */

    int digestsize;

} SHAobject;

/* When run on a little-endian CPU we need to perform byte reversal on an

   array of longwords. */

static void longReverse(SHA_INT32 *buffer, int byteCount, int Endianness)

{

    SHA_INT32 value;

    if ( Endianness == PCT_BIG_ENDIAN )

	return;

    byteCount /= sizeof(*buffer);

    while (byteCount--) {

        value = *buffer;

        value = ( ( value & 0xFF00FF00L ) >> 8  ) | \

                ( ( value & 0x00FF00FFL ) << 8 );

        *buffer++ = ( value << 16 ) | ( value >> 16 );

    }

}

static void SHAcopy(SHAobject *src, SHAobject *dest)

{

    dest->Endianness = src->Endianness;

    dest->local = src->local;

    dest->digestsize = src->digestsize;

    dest->count_lo = src->count_lo;

    dest->count_hi = src->count_hi;

    memcpy(dest->digest, src->digest, sizeof(src->digest));

    memcpy(dest->data, src->data, sizeof(src->data));

}

/* ------------------------------------------------------------------------

 *

 * This code for the SHA-256 algorithm was noted as public domain. The

 * original headers are pasted below.

 *

 * Several changes have been made to make it more compatible with the

 * Python environment and desired interface.

 *

 */

/* LibTomCrypt, modular cryptographic library -- Tom St Denis

 *

 * LibTomCrypt is a library that provides various cryptographic

 * algorithms in a highly modular and flexible manner.

 *

 * The library is free for all purposes without any express

 * gurantee it works.

 *

 * Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org

 */

/* SHA256 by Tom St Denis */

/* Various logical functions */

#define ROR(x, y)\

( ((((unsigned long)(x)&0xFFFFFFFFUL)>>(unsigned long)((y)&31)) | \

((unsigned long)(x)<<(unsigned long)(32-((y)&31)))) & 0xFFFFFFFFUL)

#define Ch(x,y,z)       (z ^ (x & (y ^ z)))

#define Maj(x,y,z)      (((x | y) & z) | (x & y)) 

#define S(x, n)         ROR((x),(n))

#define R(x, n)         (((x)&0xFFFFFFFFUL)>>(n))

#define Sigma0(x)       (S(x, 2) ^ S(x, 13) ^ S(x, 22))

#define Sigma1(x)       (S(x, 6) ^ S(x, 11) ^ S(x, 25))

#define Gamma0(x)       (S(x, 7) ^ S(x, 18) ^ R(x, 3))

#define Gamma1(x)       (S(x, 17) ^ S(x, 19) ^ R(x, 10))

static void

sha_transform(SHAobject *sha_info)

{

    int i;

	SHA_INT32 S[8], W[64], t0, t1;

    memcpy(W, sha_info->data, sizeof(sha_info->data));

    longReverse(W, (int)sizeof(sha_info->data), sha_info->Endianness);

    for (i = 16; i < 64; ++i) {

		W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) + W[i - 16];

    }

    for (i = 0; i < 8; ++i) {

        S[i] = sha_info->digest[i];

    }

    /* Compress */

#define RND(a,b,c,d,e,f,g,h,i,ki)                    \

     t0 = h + Sigma1(e) + Ch(e, f, g) + ki + W[i];   \

     t1 = Sigma0(a) + Maj(a, b, c);                  \

     d += t0;                                        \

     h  = t0 + t1;

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],0,0x428a2f98);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],1,0x71374491);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],2,0xb5c0fbcf);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],3,0xe9b5dba5);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],4,0x3956c25b);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],5,0x59f111f1);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],6,0x923f82a4);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],7,0xab1c5ed5);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],8,0xd807aa98);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],9,0x12835b01);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],10,0x243185be);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],11,0x550c7dc3);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],12,0x72be5d74);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],13,0x80deb1fe);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],14,0x9bdc06a7);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],15,0xc19bf174);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],16,0xe49b69c1);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],17,0xefbe4786);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],18,0x0fc19dc6);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],19,0x240ca1cc);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],20,0x2de92c6f);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],21,0x4a7484aa);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],22,0x5cb0a9dc);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],23,0x76f988da);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],24,0x983e5152);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],25,0xa831c66d);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],26,0xb00327c8);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],27,0xbf597fc7);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],28,0xc6e00bf3);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],29,0xd5a79147);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],30,0x06ca6351);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],31,0x14292967);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],32,0x27b70a85);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],33,0x2e1b2138);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],34,0x4d2c6dfc);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],35,0x53380d13);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],36,0x650a7354);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],37,0x766a0abb);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],38,0x81c2c92e);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],39,0x92722c85);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],40,0xa2bfe8a1);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],41,0xa81a664b);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],42,0xc24b8b70);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],43,0xc76c51a3);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],44,0xd192e819);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],45,0xd6990624);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],46,0xf40e3585);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],47,0x106aa070);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],48,0x19a4c116);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],49,0x1e376c08);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],50,0x2748774c);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],51,0x34b0bcb5);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],52,0x391c0cb3);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],53,0x4ed8aa4a);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],54,0x5b9cca4f);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],55,0x682e6ff3);

    RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],56,0x748f82ee);

    RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],57,0x78a5636f);

    RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],58,0x84c87814);

    RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],59,0x8cc70208);

    RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],60,0x90befffa);

    RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],61,0xa4506ceb);

    RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],62,0xbef9a3f7);

    RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],63,0xc67178f2);

#undef RND     

    /* feedback */

    for (i = 0; i < 8; i++) {

        sha_info->digest[i] = sha_info->digest[i] + S[i];

    }

}

/* initialize the SHA digest */

static void

sha_init(SHAobject *sha_info)

{

    TestEndianness(sha_info->Endianness)

    sha_info->digest[0] = 0x6A09E667L;

    sha_info->digest[1] = 0xBB67AE85L;

    sha_info->digest[2] = 0x3C6EF372L;

    sha_info->digest[3] = 0xA54FF53AL;

    sha_info->digest[4] = 0x510E527FL;

    sha_info->digest[5] = 0x9B05688CL;

    sha_info->digest[6] = 0x1F83D9ABL;

    sha_info->digest[7] = 0x5BE0CD19L;

    sha_info->count_lo = 0L;

    sha_info->count_hi = 0L;

    sha_info->local = 0;

    sha_info->digestsize = 32;

}

static void

sha224_init(SHAobject *sha_info)

{

    TestEndianness(sha_info->Endianness)

    sha_info->digest[0] = 0xc1059ed8L;

    sha_info->digest[1] = 0x367cd507L;

    sha_info->digest[2] = 0x3070dd17L;

    sha_info->digest[3] = 0xf70e5939L;

    sha_info->digest[4] = 0xffc00b31L;

    sha_info->digest[5] = 0x68581511L;

    sha_info->digest[6] = 0x64f98fa7L;

    sha_info->digest[7] = 0xbefa4fa4L;

    sha_info->count_lo = 0L;

    sha_info->count_hi = 0L;

    sha_info->local = 0;

    sha_info->digestsize = 28;

}

/* update the SHA digest */

static void

sha_update(SHAobject *sha_info, SHA_BYTE *buffer, int count)

{

    int i;

    SHA_INT32 clo;

    clo = sha_info->count_lo + ((SHA_INT32) count << 3);

    if (clo < sha_info->count_lo) {

        ++sha_info->count_hi;

    }

    sha_info->count_lo = clo;

    sha_info->count_hi += (SHA_INT32) count >> 29;

    if (sha_info->local) {

        i = SHA_BLOCKSIZE - sha_info->local;

        if (i > count) {

            i = count;

        }

        memcpy(((SHA_BYTE *) sha_info->data) + sha_info->local, buffer, i);

        count -= i;

        buffer += i;

        sha_info->local += i;

        if (sha_info->local == SHA_BLOCKSIZE) {

            sha_transform(sha_info);

        }

        else {

            return;

        }

    }

    while (count >= SHA_BLOCKSIZE) {

        memcpy(sha_info->data, buffer, SHA_BLOCKSIZE);

        buffer += SHA_BLOCKSIZE;

        count -= SHA_BLOCKSIZE;

        sha_transform(sha_info);

    }

    memcpy(sha_info->data, buffer, count);

    sha_info->local = count;

}

/* finish computing the SHA digest */

static void

sha_final(unsigned char digest[SHA_DIGESTSIZE], SHAobject *sha_info)

{

    int count;

    SHA_INT32 lo_bit_count, hi_bit_count;

    lo_bit_count = sha_info->count_lo;

    hi_bit_count = sha_info->count_hi;

    count = (int) ((lo_bit_count >> 3) & 0x3f);

    ((SHA_BYTE *) sha_info->data)[count++] = 0x80;

    if (count > SHA_BLOCKSIZE - 8) {

	memset(((SHA_BYTE *) sha_info->data) + count, 0,

	       SHA_BLOCKSIZE - count);

	sha_transform(sha_info);

	memset((SHA_BYTE *) sha_info->data, 0, SHA_BLOCKSIZE - 8);

    }

    else {

	memset(((SHA_BYTE *) sha_info->data) + count, 0,

	       SHA_BLOCKSIZE - 8 - count);

    }

    /* GJS: note that we add the hi/lo in big-endian. sha_transform will

       swap these values into host-order. */

    sha_info->data[56] = (hi_bit_count >> 24) & 0xff;

    sha_info->data[57] = (hi_bit_count >> 16) & 0xff;

    sha_info->data[58] = (hi_bit_count >>  8) & 0xff;

    sha_info->data[59] = (hi_bit_count >>  0) & 0xff;

    sha_info->data[60] = (lo_bit_count >> 24) & 0xff;

    sha_info->data[61] = (lo_bit_count >> 16) & 0xff;

    sha_info->data[62] = (lo_bit_count >>  8) & 0xff;

    sha_info->data[63] = (lo_bit_count >>  0) & 0xff;

    sha_transform(sha_info);

    digest[ 0] = (unsigned char) ((sha_info->digest[0] >> 24) & 0xff);

    digest[ 1] = (unsigned char) ((sha_info->digest[0] >> 16) & 0xff);

    digest[ 2] = (unsigned char) ((sha_info->digest[0] >>  8) & 0xff);

    digest[ 3] = (unsigned char) ((sha_info->digest[0]      ) & 0xff);

    digest[ 4] = (unsigned char) ((sha_info->digest[1] >> 24) & 0xff);

    digest[ 5] = (unsigned char) ((sha_info->digest[1] >> 16) & 0xff);

    digest[ 6] = (unsigned char) ((sha_info->digest[1] >>  8) & 0xff);

    digest[ 7] = (unsigned char) ((sha_info->digest[1]      ) & 0xff);

    digest[ 8] = (unsigned char) ((sha_info->digest[2] >> 24) & 0xff);

    digest[ 9] = (unsigned char) ((sha_info->digest[2] >> 16) & 0xff);

    digest[10] = (unsigned char) ((sha_info->digest[2] >>  8) & 0xff);

    digest[11] = (unsigned char) ((sha_info->digest[2]      ) & 0xff);

    digest[12] = (unsigned char) ((sha_info->digest[3] >> 24) & 0xff);

    digest[13] = (unsigned char) ((sha_info->digest[3] >> 16) & 0xff);

    digest[14] = (unsigned char) ((sha_info->digest[3] >>  8) & 0xff);

    digest[15] = (unsigned char) ((sha_info->digest[3]      ) & 0xff);

    digest[16] = (unsigned char) ((sha_info->digest[4] >> 24) & 0xff);

    digest[17] = (unsigned char) ((sha_info->digest[4] >> 16) & 0xff);

    digest[18] = (unsigned char) ((sha_info->digest[4] >>  8) & 0xff);

    digest[19] = (unsigned char) ((sha_info->digest[4]      ) & 0xff);

    digest[20] = (unsigned char) ((sha_info->digest[5] >> 24) & 0xff);

    digest[21] = (unsigned char) ((sha_info->digest[5] >> 16) & 0xff);

    digest[22] = (unsigned char) ((sha_info->digest[5] >>  8) & 0xff);

    digest[23] = (unsigned char) ((sha_info->digest[5]      ) & 0xff);

    digest[24] = (unsigned char) ((sha_info->digest[6] >> 24) & 0xff);

    digest[25] = (unsigned char) ((sha_info->digest[6] >> 16) & 0xff);

    digest[26] = (unsigned char) ((sha_info->digest[6] >>  8) & 0xff);

    digest[27] = (unsigned char) ((sha_info->digest[6]      ) & 0xff);

    digest[28] = (unsigned char) ((sha_info->digest[7] >> 24) & 0xff);

    digest[29] = (unsigned char) ((sha_info->digest[7] >> 16) & 0xff);

    digest[30] = (unsigned char) ((sha_info->digest[7] >>  8) & 0xff);

    digest[31] = (unsigned char) ((sha_info->digest[7]      ) & 0xff);

}

/*

 * End of copied SHA code.

 *

 * ------------------------------------------------------------------------

 */

static PyTypeObject SHA224type;

static PyTypeObject SHA256type;

static SHAobject *

newSHA224object(void)

{

    return (SHAobject *)PyObject_New(SHAobject, &SHA224type);

}

static SHAobject *

newSHA256object(void)

{

    return (SHAobject *)PyObject_New(SHAobject, &SHA256type);

}

/* Internal methods for a hash object */

static void

SHA_dealloc(PyObject *ptr)

{

    PyObject_Del(ptr);

}

/* External methods for a hash object */

PyDoc_STRVAR(SHA256_copy__doc__, "Return a copy of the hash object.");

static PyObject *

SHA256_copy(SHAobject *self, PyObject *unused)

{

    SHAobject *newobj;

    if (Py_TYPE(self) == &SHA256type) {

        if ( (newobj = newSHA256object())==NULL)

            return NULL;

    } else {

        if ( (newobj = newSHA224object())==NULL)

            return NULL;

    }

    SHAcopy(self, newobj);

    return (PyObject *)newobj;

}

PyDoc_STRVAR(SHA256_digest__doc__,

"Return the digest value as a string of binary data.");

static PyObject *

SHA256_digest(SHAobject *self, PyObject *unused)

{

    unsigned char digest[SHA_DIGESTSIZE];

    SHAobject temp;

    SHAcopy(self, &temp);

    sha_final(digest, &temp);

    return PyString_FromStringAndSize((const char *)digest, self->digestsize);

}

PyDoc_STRVAR(SHA256_hexdigest__doc__,

"Return the digest value as a string of hexadecimal digits.");

static PyObject *

SHA256_hexdigest(SHAobject *self, PyObject *unused)

{

    unsigned char digest[SHA_DIGESTSIZE];

    SHAobject temp;

    PyObject *retval;

    char *hex_digest;

    int i, j;

    /* Get the raw (binary) digest value */

    SHAcopy(self, &temp);

    sha_final(digest, &temp);

    /* Create a new string */

    retval = PyString_FromStringAndSize(NULL, self->digestsize * 2);

    if (!retval)

	    return NULL;

    hex_digest = PyString_AsString(retval);

    if (!hex_digest) {

	    Py_DECREF(retval);

	    return NULL;

    }

    /* Make hex version of the digest */

    for(i=j=0; i<self->digestsize; i++) {

        char c;

        c = (digest[i] >> 4) & 0xf;

	c = (c>9) ? c+'a'-10 : c + '0';

        hex_digest[j++] = c;

        c = (digest[i] & 0xf);

	c = (c>9) ? c+'a'-10 : c + '0';

        hex_digest[j++] = c;

    }

    return retval;

}

PyDoc_STRVAR(SHA256_update__doc__,

"Update this hash object's state with the provided string.");

static PyObject *

SHA256_update(SHAobject *self, PyObject *args)

{

    unsigned char *cp;

    int len;

    if (!PyArg_ParseTuple(args, "s#:update", &cp, &len))

        return NULL;

    sha_update(self, cp, len);

    Py_INCREF(Py_None);

    return Py_None;

}

static PyMethodDef SHA_methods[] = {

    {"copy",	  (PyCFunction)SHA256_copy,      METH_NOARGS,  SHA256_copy__doc__},

    {"digest",	  (PyCFunction)SHA256_digest,    METH_NOARGS,  SHA256_digest__doc__},

    {"hexdigest", (PyCFunction)SHA256_hexdigest, METH_NOARGS,  SHA256_hexdigest__doc__},

    {"update",	  (PyCFunction)SHA256_update,    METH_VARARGS, SHA256_update__doc__},

    {NULL,	  NULL}		/* sentinel */

};

static PyObject *

SHA256_get_block_size(PyObject *self, void *closure)

{

    return PyInt_FromLong(SHA_BLOCKSIZE);

}

static PyObject *

SHA256_get_name(PyObject *self, void *closure)

{

    if (((SHAobject *)self)->digestsize == 32)

        return PyString_FromStringAndSize("SHA256", 6);

    else

        return PyString_FromStringAndSize("SHA224", 6);

}

static PyGetSetDef SHA_getseters[] = {

    {"block_size",

     (getter)SHA256_get_block_size, NULL,

     NULL,

     NULL},

    {"name",

     (getter)SHA256_get_name, NULL,

     NULL,

     NULL},

    {NULL}  /* Sentinel */

};