/*
* mpbaddmod_w
* computes the sum (modulo b) of x and y
* needs a workspace of (4*size+2) words
*/
void mpbaddmod_w(const mpbarrett* b, size_t xsize, const mpw* xdata, size_t ysize, const mpw* ydata, mpw* result, mpw* wksp)
{
/* xsize and ysize must be less than or equal to b->size */
register size_t size = b->size;
register mpw* temp = wksp + size*2+2;
mpsetx(2*size, temp, xsize, xdata);
mpaddx(2*size, temp, ysize, ydata);
mpbmod_w(b, temp, result, wksp);
}
/*
* mpbsubmod_w
* computes the difference (modulo b) of x and y
* needs a workspace of (4*size+2) words
*/
void mpbsubmod_w(const mpbarrett* b, size_t xsize, const mpw* xdata, size_t ysize, const mpw* ydata, mpw* result, mpw* wksp)
{
/* xsize and ysize must be less than or equal to b->size */
register size_t size = b->size;
register mpw* temp = wksp + size*2+2;
mpsetx(2*size, temp, xsize, xdata);
if (mpsubx(2*size, temp, ysize, ydata)) /* if there's carry, i.e. the result would be negative, add the modulus */
while (!mpaddx(2*size, temp, size, b->modl)); /* keep adding the modulus until we get a carry */
mpbmod_w(b, temp, result, wksp);
}
/*
* mpbsqrmod_w
* computes the square (modulo b) of x
* needs a workspace of (4*size+2) words
*/
void mpbsqrmod_w(const mpbarrett* b, size_t xsize, const mpw* xdata, mpw* result, mpw* wksp)
{
/* xsize must be <= b->size */
register size_t size = b->size;
register mpw* temp = wksp + size*2+2;
register mpw fill = 2*(size-xsize);
if (fill)
mpzero(fill, temp);
mpsqr(temp+fill, xsize, xdata);
mpbmod_w(b, temp, result, wksp);
}
/*
* mpmulmod_w
* computes the product (modulo b) of x and y
* needs a workspace of (4*size+2) words
*/
void mpbmulmod_w(const mpbarrett* b, size_t xsize, const mpw* xdata, size_t ysize, const mpw* ydata, mpw* result, mpw* wksp)
{
/* xsize and ysize must be <= b->size */
register size_t size = b->size;
register mpw* temp = wksp + size*2+2;
register mpw fill = size*2-xsize-ysize;
if (fill)
mpzero(fill, temp);
mpmul(temp+fill, xsize, xdata, ysize, ydata);
mpbmod_w(b, temp, result, wksp);
}
void mpbnsqrmod(const mpbarrett* b, const mpnumber* x, mpnumber* result)
{
register size_t size = b->size;
register mpw* temp = (mpw*) malloc(size * sizeof(mpw));
/* xsize must be <= b->size */
register size_t fill = 2*(size-x->size);
register mpw* opnd = temp + size*2+2;
if (fill)
mpzero(fill, opnd);
mpsqr(opnd+fill, x->size, x->data);
mpnsize(result, size);
mpbmod_w(b, opnd, result->data, temp);
free(temp);
}
void mpbnmulmod(const mpbarrett* b, const mpnumber* x, const mpnumber* y, mpnumber* result)
{
register size_t size = b->size;
register mpw* temp = (mpw*) malloc((4*size+2) * sizeof(mpw));
/* xsize and ysize must be <= b->size */
register size_t fill = 2*size-x->size-y->size;
register mpw* opnd = temp+size*2+2;
mpnfree(result);
mpnsize(result, size);
if (fill)
mpzero(fill, opnd);
mpmul(opnd+fill, x->size, x->data, y->size, y->data);
mpbmod_w(b, opnd, result->data, temp);
free(temp);
}
int main( int argc, char **argv ) {
FILE *secblock;
unsigned char packetType;
unsigned short packetLen;
unsigned char buffer[4096];
unsigned char hexrep[8192];
// for CRT computation
mpbarrett psubone, qsubone;
// for testing
mpnumber m, cipher, decipher, holder;
rsakp keypair;
size_t bits = 2048;
size_t pbits = (bits+1) >> 1;
size_t qbits = (bits - pbits);
size_t psize = MP_BITS_TO_WORDS(pbits+MP_WBITS-1);
size_t qsize = MP_BITS_TO_WORDS(qbits+MP_WBITS-1);
size_t pqsize = psize+qsize;
mpw* temp = (mpw*) malloc((16*pqsize+6)*sizeof(mpw));
if( argc < 2 ) {
printf( "usage: %s <secblock>\n", argv[0] );
exit( 1 );
}
mpbzero(&psubone);
mpbzero(&qsubone);
secblock = fopen(argv[1], "rb");
if( secblock == NULL ) {
printf( "Can't open %s\n", argv[1] );
exit(0);
}
packetType = fgetc(secblock);
packetLen = 0;
//big endianness...
big16read(&packetLen, secblock);
printf( "Packet type: 0x%02X\n", packetType );
printf( "Packet length: %04d\n", (int) packetLen );
// skip ahead six bytes, this includes key generation time and other attributes
fread( buffer, 6, 1, secblock);
rsakpInit(&keypair);
big16read(&packetLen, secblock);
printf( "n Packet length: %02d bits, %02d bytes\n", (int) packetLen, (int) bytesFromMpn(packetLen) );
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
mpbsetbin(&keypair.n, buffer, bytesFromMpn(packetLen));
mpprintln(packetLen/32, keypair.n.modl);
big16read(&packetLen, secblock);
printf( "e Packet length: %02d bits, %02d bytes\n", (int) packetLen, (int) bytesFromMpn(packetLen) );
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
mpnsetbin(&keypair.e, buffer, bytesFromMpn(packetLen));
mpprintln(keypair.e.size, keypair.e.data);
packetType = fgetc(secblock);
if( packetType == 0 ) {
printf( "secret data is plaintext\n" );
} else {
printf( "secret data is encrypted\n" );
}
big16read(&packetLen, secblock);
printf( "d Packet length: %02d bits, %02d bytes\n", (int) packetLen, (int) bytesFromMpn(packetLen) );
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
mpnsetbin(&keypair.d, buffer, bytesFromMpn(packetLen));
mpprintln(keypair.d.size, keypair.d.data);
big16read(&packetLen, secblock);
printf( "p Packet length: %02d bits, %02d bytes\n", (int) packetLen, (int) bytesFromMpn(packetLen) );
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
mpbsetbin(&keypair.p, buffer, bytesFromMpn(packetLen));
mpprintln(packetLen/32, keypair.p.modl);
big16read(&packetLen, secblock);
printf( "q Packet length: %02d bits, %02d bytes\n", (int) packetLen, (int) bytesFromMpn(packetLen) );
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
mpbsetbin(&keypair.q, buffer, bytesFromMpn(packetLen));
mpprintln(packetLen/32, keypair.q.modl);
big16read(&packetLen, secblock);
printf( "mystery packet length: %02d bits, %02d bytes\n", (int) packetLen, (int) bytesFromMpn(packetLen) );
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
mpnzero(&holder);
mpnsetbin(&holder, buffer, bytesFromMpn(packetLen));
mpprintln(holder.size, holder.data);
fread( buffer, 4, 1, secblock ); // advance by two bytes
printf( "offset: %x\n", ftell( secblock ) );
fread( buffer, bytesFromMpn(packetLen), 1, secblock );
printf( "%s\n", buffer );
#ifdef USE_CRT
// compute CRT elements
/* compute p-1 */
mpbsubone(&keypair.p, temp);
mpbset(&psubone, psize, temp);
/* compute q-1 */
mpbsubone(&keypair.q, temp);
mpbset(&qsubone, qsize, temp);
/* compute dp = d mod (p-1) */
mpnsize(&keypair.dp, psize);
mpbmod_w(&psubone, keypair.d.data, keypair.dp.data, temp);
/* compute dq = d mod (q-1) */
mpnsize(&keypair.dq, qsize);
mpbmod_w(&qsubone, keypair.d.data, keypair.dq.data, temp);
/* compute qi = inv(q) mod p */
mpninv(&keypair.qi, (mpnumber*) &keypair.q, (mpnumber*) &keypair.p);
#endif
// now test
mpnzero(&m);
mpnzero(&cipher);
mpnzero(&decipher);
mpnsethex(&m, "d436e99569fd32a7c8a05bbc90d32c49");
printf( "Original: " );
mpprintln(m.size, m.data);
rsapub(&keypair.n, &keypair.e, &m, &cipher);
printf( "Encrypted: " );
mpprintln(cipher.size, cipher.data);
#ifdef USE_CRT
rsapricrt(&keypair.n, &keypair.p, &keypair.q, &keypair.dp, &keypair.dq, &keypair.qi, &cipher, &decipher);
#else
rsapri(&keypair.n, &keypair.d, &cipher, &decipher);
#endif
printf( "Recovered: " );
mpprintln(decipher.size, decipher.data);
if (mpnex(m.size, m.data, decipher.size, decipher.data))
printf ( "results don't match\n" );
else
printf ( "before and after encyrption sizes match\n" );
printf( "special test routine for STM32 validation\n" );
mpnzero(&cipher);
mpnzero(&decipher);
mpnsethex(&cipher, "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" );
printf( "Decrypting: " );
mpprintln(cipher.size, cipher.data);
rsapub(&keypair.n, &keypair.e, &cipher, &decipher);
printf( "Recovered: " );
mpprintln(decipher.size, decipher.data);
free(temp);
return 0;
}
