diff options
Diffstat (limited to 'libtomcrypt/src/pk/ecc/ecc.c')
| -rw-r--r-- | libtomcrypt/src/pk/ecc/ecc.c | 1036 |
1 files changed, 1036 insertions, 0 deletions
diff --git a/libtomcrypt/src/pk/ecc/ecc.c b/libtomcrypt/src/pk/ecc/ecc.c new file mode 100644 index 0000000..469d56d --- /dev/null +++ b/libtomcrypt/src/pk/ecc/ecc.c @@ -0,0 +1,1036 @@ +/* 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 + * guarantee it works. + * + * Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.org + */ + +/* Implements ECC over Z/pZ for curve y^2 = x^3 - 3x + b + * + * All curves taken from NIST recommendation paper of July 1999 + * Available at http://csrc.nist.gov/cryptval/dss.htm + */ +#include "tomcrypt.h" + +/** + @file ecc.c + ECC Crypto, Tom St Denis +*/ + +#ifdef MECC + +/* size of our temp buffers for exported keys */ +#define ECC_BUF_SIZE 256 + +/* max private key size */ +#define ECC_MAXSIZE 66 + +/* This holds the key settings. ***MUST*** be organized by size from smallest to largest. */ +static const struct { + int size; + char *name, *prime, *B, *order, *Gx, *Gy; +} sets[] = { +#ifdef ECC192 +{ + 24, + "ECC-192", + /* prime */ + "/////////////////////l//////////", + + /* B */ + "P2456UMSWESFf+chSYGmIVwutkp1Hhcn", + + /* order */ + "////////////////cTxuDXHhoR6qqYWn", + + /* Gx */ + "68se3h0maFPylo3hGw680FJ/2ls2/n0I", + + /* Gy */ + "1nahbV/8sdXZ417jQoJDrNFvTw4UUKWH" +}, +#endif +#ifdef ECC224 +{ + 28, + "ECC-224", + + /* prime */ + "3/////////////////////0000000000000001", + + /* B */ + "2q1Gg530Ipg/L1CbPGHB2trx/OkYSBEKCZLV+q", + + /* order */ + "3//////////////////nQYuBZmFXFTAKLSN2ez", + + /* Gx */ + "2t3WozQxI/Vp8JaBbA0y7JLi8H8ZGoWDOHN1qX", + + + /* Gy */ + "2zDsE8jVSZ+qmYt+RDGtMWMWT7P4JLWPc507uq", +}, +#endif +#ifdef ECC256 +{ + 32, + "ECC-256", + /* Prime */ + "F////y000010000000000000000////////////////", + + /* B */ + "5h6DTYgEfFdi+kzLNQOXhnb7GQmp5EmzZlEF3udqc1B", + + /* Order */ + "F////y00000//////////+yvlgjfnUUXFEvoiByOoLH", + + /* Gx */ + "6iNqVBXB497+BpcvMEaGF9t0ts1BUipeFIXEKNOcCAM", + + /* Gy */ + "4/ZGkB+6d+RZkVhIdmFdXOhpZDNQp5UpiksG6Wtlr7r" +}, +#endif +#ifdef ECC384 +{ + 48, + "ECC-384", + /* prime */ + "//////////////////////////////////////////x/////00000000003/" + "////", + + /* B */ + "ip4lf+8+v+IOZWLhu/Wj6HWTd6x+WK4I0nG8Zr0JXrh6LZcDYYxHdIg5oEtJ" + "x2hl", + + /* Order */ + "////////////////////////////////nsDDWVGtBTzO6WsoIB2dUkpi6MhC" + "nIbp", + + /* Gx and Gy */ + "geVA8hwB1JUEiSSUyo2jT6uTEsABfvkOMVT1u89KAZXL0l9TlrKfR3fKNZXo" + "TWgt", + + "DXVUIfOcB6zTdfY/afBSAVZq7RqecXHywTen4xNmkC0AOB7E7Nw1dNf37NoG" + "wWvV" +}, +#endif +#ifdef ECC521 +{ + 65, + "ECC-521", + /* prime */ + "V///////////////////////////////////////////////////////////" + "///////////////////////////", + + /* B */ + "56LFhbXZXoQ7vAQ8Q2sXK3kejfoMvcp5VEuj8cHZl49uLOPEL7iVfDx5bB0l" + "JknlmSrSz+8FImqyUz57zHhK3y0", + + /* Order */ + "V//////////////////////////////////////////+b66XuE/BvPhVym1I" + "FS9fT0xjScuYPn7hhjljnwHE6G9", + + /* Gx and Gy */ + "CQ5ZWQt10JfpPu+osOZbRH2d6I1EGK/jI7uAAzWQqqzkg5BNdVlvrae/Xt19" + "wB/gDupIBF1XMf2c/b+VZ72vRrc", + + "HWvAMfucZl015oANxGiVHlPcFL4ILURH6WNhxqN9pvcB9VkSfbUz2P0nL2v0" + "J+j1s4rF726edB2G8Y+b7QVqMPG", +}, +#endif +{ + 0, + NULL, NULL, NULL, NULL, NULL, NULL +} +}; + +static int is_valid_idx(int n) +{ + int x; + + for (x = 0; sets[x].size != 0; x++); + if ((n < 0) || (n >= x)) { + return 0; + } + return 1; +} + +static ecc_point *new_point(void) +{ + ecc_point *p; + p = XMALLOC(sizeof(ecc_point)); + if (p == NULL) { + return NULL; + } + if (mp_init_multi(&p->x, &p->y, &p->z, NULL) != MP_OKAY) { + XFREE(p); + return NULL; + } + return p; +} + +static void del_point(ecc_point *p) +{ + /* prevents free'ing null arguments */ + if (p != NULL) { + mp_clear_multi(&p->x, &p->y, &p->z, NULL); + XFREE(p); + } +} + +static int ecc_map(ecc_point *P, mp_int *modulus, mp_digit mp) +{ + mp_int t1, t2; + int err; + + if ((err = mp_init_multi(&t1, &t2, NULL)) != CRYPT_OK) { + return CRYPT_MEM; + } + + /* first map z back to normal */ + if ((err = mp_montgomery_reduce(&P->z, modulus, mp)) != MP_OKAY) { goto error; } + + /* get 1/z */ + if ((err = mp_invmod(&P->z, modulus, &t1)) != MP_OKAY) { goto error; } + + /* get 1/z^2 and 1/z^3 */ + if ((err = mp_sqr(&t1, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_mod(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_mul(&t1, &t2, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_mod(&t1, modulus, &t1)) != MP_OKAY) { goto error; } + + /* multiply against x/y */ + if ((err = mp_mul(&P->x, &t2, &P->x)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&P->x, modulus, mp)) != MP_OKAY) { goto error; } + if ((err = mp_mul(&P->y, &t1, &P->y)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&P->y, modulus, mp)) != MP_OKAY) { goto error; } + mp_set(&P->z, 1); + + err = CRYPT_OK; + goto done; +error: + err = mpi_to_ltc_error(err); +done: + mp_clear_multi(&t1, &t2, NULL); + return err; + +} + +/* double a point R = 2P, R can be P*/ +static int dbl_point(ecc_point *P, ecc_point *R, mp_int *modulus, mp_digit mp) +{ + mp_int t1, t2; + int err; + + if ((err = mp_init_multi(&t1, &t2, NULL)) != MP_OKAY) { + return mpi_to_ltc_error(err); + } + + if ((err = mp_copy(&P->x, &R->x)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&P->y, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&P->z, &R->z)) != MP_OKAY) { goto error; } + + /* t1 = Z * Z */ + if ((err = mp_sqr(&R->z, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + /* Z = Y * Z */ + if ((err = mp_mul(&R->z, &R->y, &R->z)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&R->z, modulus, mp)) != MP_OKAY) { goto error; } + /* Z = 2Z */ + if ((err = mp_mul_2(&R->z, &R->z)) != MP_OKAY) { goto error; } + if (mp_cmp(&R->z, modulus) != MP_LT) { + if ((err = mp_sub(&R->z, modulus, &R->z)) != MP_OKAY) { goto error; } + } + + /* T2 = X - T1 */ + if ((err = mp_sub(&R->x, &t1, &t2)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&t2, 0) == MP_LT) { + if ((err = mp_add(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + } + /* T1 = X + T1 */ + if ((err = mp_add(&t1, &R->x, &t1)) != MP_OKAY) { goto error; } + if (mp_cmp(&t1, modulus) != MP_LT) { + if ((err = mp_sub(&t1, modulus, &t1)) != MP_OKAY) { goto error; } + } + /* T2 = T1 * T2 */ + if ((err = mp_mul(&t1, &t2, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t2, modulus, mp)) != MP_OKAY) { goto error; } + /* T1 = 2T2 */ + if ((err = mp_mul_2(&t2, &t1)) != MP_OKAY) { goto error; } + if (mp_cmp(&t1, modulus) != MP_LT) { + if ((err = mp_sub(&t1, modulus, &t1)) != MP_OKAY) { goto error; } + } + /* T1 = T1 + T2 */ + if ((err = mp_add(&t1, &t2, &t1)) != MP_OKAY) { goto error; } + if (mp_cmp(&t1, modulus) != MP_LT) { + if ((err = mp_sub(&t1, modulus, &t1)) != MP_OKAY) { goto error; } + } + + /* Y = 2Y */ + if ((err = mp_mul_2(&R->y, &R->y)) != MP_OKAY) { goto error; } + if (mp_cmp(&R->y, modulus) != MP_LT) { + if ((err = mp_sub(&R->y, modulus, &R->y)) != MP_OKAY) { goto error; } + } + /* Y = Y * Y */ + if ((err = mp_sqr(&R->y, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&R->y, modulus, mp)) != MP_OKAY) { goto error; } + /* T2 = Y * Y */ + if ((err = mp_sqr(&R->y, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t2, modulus, mp)) != MP_OKAY) { goto error; } + /* T2 = T2/2 */ + if (mp_isodd(&t2)) { + if ((err = mp_add(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + } + if ((err = mp_div_2(&t2, &t2)) != MP_OKAY) { goto error; } + /* Y = Y * X */ + if ((err = mp_mul(&R->y, &R->x, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&R->y, modulus, mp)) != MP_OKAY) { goto error; } + + /* X = T1 * T1 */ + if ((err = mp_sqr(&t1, &R->x)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&R->x, modulus, mp)) != MP_OKAY) { goto error; } + /* X = X - Y */ + if ((err = mp_sub(&R->x, &R->y, &R->x)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&R->x, 0) == MP_LT) { + if ((err = mp_add(&R->x, modulus, &R->x)) != MP_OKAY) { goto error; } + } + /* X = X - Y */ + if ((err = mp_sub(&R->x, &R->y, &R->x)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&R->x, 0) == MP_LT) { + if ((err = mp_add(&R->x, modulus, &R->x)) != MP_OKAY) { goto error; } + } + + /* Y = Y - X */ + if ((err = mp_sub(&R->y, &R->x, &R->y)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&R->y, 0) == MP_LT) { + if ((err = mp_add(&R->y, modulus, &R->y)) != MP_OKAY) { goto error; } + } + /* Y = Y * T1 */ + if ((err = mp_mul(&R->y, &t1, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&R->y, modulus, mp)) != MP_OKAY) { goto error; } + /* Y = Y - T2 */ + if ((err = mp_sub(&R->y, &t2, &R->y)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&R->y, 0) == MP_LT) { + if ((err = mp_add(&R->y, modulus, &R->y)) != MP_OKAY) { goto error; } + } + + err = CRYPT_OK; + goto done; +error: + err = mpi_to_ltc_error(err); +done: + mp_clear_multi(&t1, &t2, NULL); + return err; +} + +/* add two different points over Z/pZ, R = P + Q, note R can equal either P or Q */ +static int add_point(ecc_point *P, ecc_point *Q, ecc_point *R, mp_int *modulus, mp_digit mp) +{ + mp_int t1, t2, x, y, z; + int err; + + if ((err = mp_init_multi(&t1, &t2, &x, &y, &z, NULL)) != MP_OKAY) { + return mpi_to_ltc_error(err); + } + + if ((err = mp_copy(&P->x, &x)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&P->y, &y)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&P->z, &z)) != MP_OKAY) { goto error; } + + /* T1 = Z' * Z' */ + if ((err = mp_sqr(&Q->z, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + /* X = X * T1 */ + if ((err = mp_mul(&t1, &x, &x)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&x, modulus, mp)) != MP_OKAY) { goto error; } + /* T1 = Z' * T1 */ + if ((err = mp_mul(&Q->z, &t1, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + /* Y = Y * T1 */ + if ((err = mp_mul(&t1, &y, &y)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&y, modulus, mp)) != MP_OKAY) { goto error; } + + /* T1 = Z*Z */ + if ((err = mp_sqr(&z, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + /* T2 = X' * T1 */ + if ((err = mp_mul(&Q->x, &t1, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t2, modulus, mp)) != MP_OKAY) { goto error; } + /* T1 = Z * T1 */ + if ((err = mp_mul(&z, &t1, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + /* T1 = Y' * T1 */ + if ((err = mp_mul(&Q->y, &t1, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + + /* Y = Y - T1 */ + if ((err = mp_sub(&y, &t1, &y)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&y, 0) == MP_LT) { + if ((err = mp_add(&y, modulus, &y)) != MP_OKAY) { goto error; } + } + /* T1 = 2T1 */ + if ((err = mp_mul_2(&t1, &t1)) != MP_OKAY) { goto error; } + if (mp_cmp(&t1, modulus) != MP_LT) { + if ((err = mp_sub(&t1, modulus, &t1)) != MP_OKAY) { goto error; } + } + /* T1 = Y + T1 */ + if ((err = mp_add(&t1, &y, &t1)) != MP_OKAY) { goto error; } + if (mp_cmp(&t1, modulus) != MP_LT) { + if ((err = mp_sub(&t1, modulus, &t1)) != MP_OKAY) { goto error; } + } + /* X = X - T2 */ + if ((err = mp_sub(&x, &t2, &x)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&x, 0) == MP_LT) { + if ((err = mp_add(&x, modulus, &x)) != MP_OKAY) { goto error; } + } + /* T2 = 2T2 */ + if ((err = mp_mul_2(&t2, &t2)) != MP_OKAY) { goto error; } + if (mp_cmp(&t2, modulus) != MP_LT) { + if ((err = mp_sub(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + } + /* T2 = X + T2 */ + if ((err = mp_add(&t2, &x, &t2)) != MP_OKAY) { goto error; } + if (mp_cmp(&t2, modulus) != MP_LT) { + if ((err = mp_sub(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + } + + /* if Z' != 1 */ + if (mp_cmp_d(&Q->z, 1) != MP_EQ) { + /* Z = Z * Z' */ + if ((err = mp_mul(&z, &Q->z, &z)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&z, modulus, mp)) != MP_OKAY) { goto error; } + } + /* Z = Z * X */ + if ((err = mp_mul(&z, &x, &z)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&z, modulus, mp)) != MP_OKAY) { goto error; } + + /* T1 = T1 * X */ + if ((err = mp_mul(&t1, &x, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + /* X = X * X */ + if ((err = mp_sqr(&x, &x)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&x, modulus, mp)) != MP_OKAY) { goto error; } + /* T2 = T2 * x */ + if ((err = mp_mul(&t2, &x, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t2, modulus, mp)) != MP_OKAY) { goto error; } + /* T1 = T1 * X */ + if ((err = mp_mul(&t1, &x, &t1)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t1, modulus, mp)) != MP_OKAY) { goto error; } + + /* X = Y*Y */ + if ((err = mp_sqr(&y, &x)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&x, modulus, mp)) != MP_OKAY) { goto error; } + /* X = X - T2 */ + if ((err = mp_sub(&x, &t2, &x)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&x, 0) == MP_LT) { + if ((err = mp_add(&x, modulus, &x)) != MP_OKAY) { goto error; } + } + + /* T2 = T2 - X */ + if ((err = mp_sub(&t2, &x, &t2)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&t2, 0) == MP_LT) { + if ((err = mp_add(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + } + /* T2 = T2 - X */ + if ((err = mp_sub(&t2, &x, &t2)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&t2, 0) == MP_LT) { + if ((err = mp_add(&t2, modulus, &t2)) != MP_OKAY) { goto error; } + } + /* T2 = T2 * Y */ + if ((err = mp_mul(&t2, &y, &t2)) != MP_OKAY) { goto error; } + if ((err = mp_montgomery_reduce(&t2, modulus, mp)) != MP_OKAY) { goto error; } + /* Y = T2 - T1 */ + if ((err = mp_sub(&t2, &t1, &y)) != MP_OKAY) { goto error; } + if (mp_cmp_d(&y, 0) == MP_LT) { + if ((err = mp_add(&y, modulus, &y)) != MP_OKAY) { goto error; } + } + /* Y = Y/2 */ + if (mp_isodd(&y)) { + if ((err = mp_add(&y, modulus, &y)) != MP_OKAY) { goto error; } + } + if ((err = mp_div_2(&y, &y)) != MP_OKAY) { goto error; } + + if ((err = mp_copy(&x, &R->x)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&y, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&z, &R->z)) != MP_OKAY) { goto error; } + + err = CRYPT_OK; + goto done; +error: + err = mpi_to_ltc_error(err); +done: + mp_clear_multi(&t1, &t2, &x, &y, &z, NULL); + return err; +} + +/* size of sliding window, don't change this! */ +#define WINSIZE 4 + +/* perform R = kG where k == integer and G == ecc_point */ +static int ecc_mulmod(mp_int *k, ecc_point *G, ecc_point *R, mp_int *modulus, int map) +{ + ecc_point *tG, *M[8]; + int i, j, err; + mp_int mu; + mp_digit buf, mp; + int first, bitbuf, bitcpy, bitcnt, mode, digidx; + + /* init montgomery reduction */ + if ((err = mp_montgomery_setup(modulus, &mp)) != MP_OKAY) { + return CRYPT_INVALID_ARG; + } + if ((err = mp_init(&mu)) != MP_OKAY) { + return CRYPT_MEM; + } + if ((err = mp_montgomery_calc_normalization(&mu, modulus)) != MP_OKAY) { + mp_clear(&mu); + return CRYPT_INVALID_ARG; + } + + /* alloc ram for window temps */ + for (i = 0; i < 8; i++) { + M[i] = new_point(); + if (M[i] == NULL) { + for (j = 0; j < i; j++) { + del_point(M[j]); + } + mp_clear(&mu); + return CRYPT_MEM; + } + } + + /* make a copy of G incase R==G */ + tG = new_point(); + if (tG == NULL) { err = CRYPT_MEM; goto done; } + + /* tG = G and convert to montgomery */ + if ((err = mp_mulmod(&G->x, &mu, modulus, &tG->x)) != MP_OKAY) { goto error; } + if ((err = mp_mulmod(&G->y, &mu, modulus, &tG->y)) != MP_OKAY) { goto error; } + if ((err = mp_mulmod(&G->z, &mu, modulus, &tG->z)) != MP_OKAY) { goto error; } + mp_clear(&mu); + + /* calc the M tab, which holds kG for k==8..15 */ + /* M[0] == 8G */ + if ((err = dbl_point(tG, M[0], modulus, mp)) != CRYPT_OK) { goto done; } + if ((err = dbl_point(M[0], M[0], modulus, mp)) != CRYPT_OK) { goto done; } + if ((err = dbl_point(M[0], M[0], modulus, mp)) != CRYPT_OK) { goto done; } + + /* now find (8+k)G for k=1..7 */ + for (j = 9; j < 16; j++) { + if ((err = add_point(M[j-9], tG, M[j-8], modulus, mp)) != CRYPT_OK) { goto done; } + } + + /* setup sliding window */ + mode = 0; + bitcnt = 1; + buf = 0; + digidx = k->used - 1; + bitcpy = bitbuf = 0; + first = 1; + + /* perform ops */ + for (;;) { + /* grab next digit as required */ + if (--bitcnt == 0) { + if (digidx == -1) { + break; + } + buf = k->dp[digidx--]; + bitcnt = (int) DIGIT_BIT; + } + + /* grab the next msb from the ltiplicand */ + i = (buf >> (DIGIT_BIT - 1)) & 1; + buf <<= 1; + + /* skip leading zero bits */ + if (mode == 0 && i == 0) { + continue; + } + + /* if the bit is zero and mode == 1 then we double */ + if (mode == 1 && i == 0) { + if ((err = dbl_point(R, R, modulus, mp)) != CRYPT_OK) { goto done; } + continue; + } + + /* else we add it to the window */ + bitbuf |= (i << (WINSIZE - ++bitcpy)); + mode = 2; + + if (bitcpy == WINSIZE) { + /* if this is the first window we do a simple copy */ + if (first == 1) { + /* R = kG [k = first window] */ + if ((err = mp_copy(&M[bitbuf-8]->x, &R->x)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&M[bitbuf-8]->y, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&M[bitbuf-8]->z, &R->z)) != MP_OKAY) { goto error; } + first = 0; + } else { + /* normal window */ + /* ok window is filled so double as required and add */ + /* double first */ + for (j = 0; j < WINSIZE; j++) { + if ((err = dbl_point(R, R, modulus, mp)) != CRYPT_OK) { goto done; } + } + + /* then add, bitbuf will be 8..15 [8..2^WINSIZE] guaranteed */ + if ((err = add_point(R, M[bitbuf-8], R, modulus, mp)) != CRYPT_OK) { goto done; } + } + /* empty window and reset */ + bitcpy = bitbuf = 0; + mode = 1; + } + } + + /* if bits remain then double/add */ + if (mode == 2 && bitcpy > 0) { + /* double then add */ + for (j = 0; j < bitcpy; j++) { + /* only double if we have had at least one add first */ + if (first == 0) { + if ((err = dbl_point(R, R, modulus, mp)) != CRYPT_OK) { goto done; } + } + + bitbuf <<= 1; + if ((bitbuf & (1 << WINSIZE)) != 0) { + if (first == 1){ + /* first add, so copy */ + if ((err = mp_copy(&tG->x, &R->x)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&tG->y, &R->y)) != MP_OKAY) { goto error; } + if ((err = mp_copy(&tG->z, &R->z)) != MP_OKAY) { goto error; } + first = 0; + } else { + /* then add */ + if ((err = add_point(R, tG, R, modulus, mp)) != CRYPT_OK) { goto done; } + } + } + } + } + + /* map R back from projective space */ + if (map) { + err = ecc_map(R, modulus, mp); + } else { + err = CRYPT_OK; + } + + goto done; +error: + err = mpi_to_ltc_error(err); +done: + del_point(tG); + for (i = 0; i < 8; i++) { + del_point(M[i]); + } + return err; +} + +#undef WINSIZE + +/** + Perform on the ECC system + @return CRYPT_OK if successful +*/ +int ecc_test(void) +{ + mp_int modulus, order; + ecc_point *G, *GG; + int i, err, primality; + + if ((err = mp_init_multi(&modulus, &order, NULL)) != MP_OKAY) { + return mpi_to_ltc_error(err); + } + + G = new_point(); + GG = new_point(); + if (G == NULL || GG == NULL) { + mp_clear_multi(&modulus, &order, NULL); + del_point(G); + del_point(GG); + return CRYPT_MEM; + } + + for (i = 0; sets[i].size; i++) { + #if 0 + printf("Testing %d\n", sets[i].size); + #endif + if ((err = mp_read_radix(&modulus, (char *)sets[i].prime, 64)) != MP_OKAY) { goto error; } + if ((err = mp_read_radix(&order, (char *)sets[i].order, 64)) != MP_OKAY) { goto error; } + + /* is prime actually prime? */ + if ((err = is_prime(&modulus, &primality)) != CRYPT_OK) { goto done; } + if (primality == 0) { + err = CRYPT_FAIL_TESTVECTOR; + goto done; + } + + /* is order prime ? */ + if ((err = is_prime(&order, &primality)) != CRYPT_OK) { goto done; } + if (primality == 0) { + err = CRYPT_FAIL_TESTVECTOR; + goto done; + } + + if ((err = mp_read_radix(&G->x, (char *)sets[i].Gx, 64)) != MP_OKAY) { goto error; } + if ((err = mp_read_radix(&G->y, (char *)sets[i].Gy, 64)) != MP_OKAY) { goto error; } + mp_set(&G->z, 1); + + /* then we should have G == (order + 1)G */ + if ((err = mp_add_d(&order, 1, &order)) != MP_OKAY) { goto error; } + if ((err = ecc_mulmod(&order, G, GG, &modulus, 1)) != CRYPT_OK) { goto done; } + if (mp_cmp(&G->x, &GG->x) != 0 || mp_cmp(&G->y, &GG->y) != 0) { + err = CRYPT_FAIL_TESTVECTOR; + goto done; + } + } + err = CRYPT_OK; + goto done; +error: + err = mpi_to_ltc_error(err); +done: + del_point(GG); + del_point(G); + mp_clear_multi(&order, &modulus, NULL); + return err; +} + +void ecc_sizes(int *low, int *high) +{ + int i; + LTC_ARGCHK(low != NULL); + LTC_ARGCHK(high != NULL); + + *low = INT_MAX; + *high = 0; + for (i = 0; sets[i].size != 0; i++) { + if (sets[i].size < *low) { + *low = sets[i].size; + } + if (sets[i].size > *high) { + *high = sets[i].size; + } + } +} + +/** + Make a new ECC key + @param prng An active PRNG state + @param wprng The index of the PRNG you wish to use + @param keysize The keysize for the new key (in octets from 20 to 65 bytes) + @param key [out] Destination of the newly created key + @return CRYPT_OK if successful, upon error all allocated memory will be freed +*/ +int ecc_make_key(prng_state *prng, int wprng, int keysize, ecc_key *key) +{ + int x, err; + ecc_point *base; + mp_int prime; + unsigned char *buf; + + LTC_ARGCHK(key != NULL); + + /* good prng? */ + if ((err = prng_is_valid(wprng)) != CRYPT_OK) { + return err; + } + + /* find key size */ + for (x = 0; (keysize > sets[x].size) && (sets[x].size != 0); x++); + keysize = sets[x].size; + + if (keysize > ECC_MAXSIZE || sets[x].size == 0) { + return CRYPT_INVALID_KEYSIZE; + } + key->idx = x; + + /* allocate ram */ + base = NULL; + buf = XMALLOC(ECC_MAXSIZE); + if (buf == NULL) { + return CRYPT_MEM; + } + + /* make up random string */ + if (prng_descriptor[wprng].read(buf, (unsigned long)keysize, prng) != (unsigned long)keysize) { + err = CRYPT_ERROR_READPRNG; + goto LBL_ERR2; + } + + /* setup the key variables */ + if ((err = mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, &prime, NULL)) != MP_OKAY) { + err = mpi_to_ltc_error(err); + goto LBL_ERR; + } + base = new_point(); + if (base == NULL) { + mp_clear_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, &prime, NULL); + err = CRYPT_MEM; + goto LBL_ERR; + } + + /* read in the specs for this key */ + if ((err = mp_read_radix(&prime, (char *)sets[key->idx].prime, 64)) != MP_OKAY) { goto error; } + if ((err = mp_read_radix(&base->x, (char *)sets[key->idx].Gx, 64)) != MP_OKAY) { goto error; } + if ((err = mp_read_radix(&base->y, (char *)sets[key->idx].Gy, 64)) != MP_OKAY) { goto error; } + mp_set(&base->z, 1); + if ((err = mp_read_unsigned_bin(&key->k, (unsigned char *)buf, keysize)) != MP_OKAY) { goto error; } + + /* make the public key */ + if ((err = ecc_mulmod(&key->k, base, &key->pubkey, &prime, 1)) != CRYPT_OK) { goto LBL_ERR; } + key->type = PK_PRIVATE; + + /* shrink key */ + if ((err = mp_shrink(&key->k)) != MP_OKAY) { goto error; } + if ((err = mp_shrink(&key->pubkey.x)) != MP_OKAY) { goto error; } + if ((err = mp_shrink(&key->pubkey.y)) != MP_OKAY) { goto error; } + if ((err = mp_shrink(&key->pubkey.z)) != MP_OKAY) { goto error; } + + /* free up ram */ + err = CRYPT_OK; + goto LBL_ERR; +error: + err = mpi_to_ltc_error(err); +LBL_ERR: + del_point(base); + mp_clear(&prime); +LBL_ERR2: +#ifdef LTC_CLEAN_STACK + zeromem(buf, ECC_MAXSIZE); +#endif + + XFREE(buf); + + return err; +} + +/** + Free an ECC key from memory + @param key The key you wish to free +*/ +void ecc_free(ecc_key *key) +{ + LTC_ARGCHK(key != NULL); + mp_clear_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL); +} + +/** + Export an ECC key as a binary packet + @param out [out] Destination for the key + @param outlen [in/out] Max size and resulting size of the exported key + @param type The type of key you want to export (PK_PRIVATE or PK_PUBLIC) + @param key The key to export + @return CRYPT_OK if successful +*/ +int ecc_export(unsigned char *out, unsigned long *outlen, int type, ecc_key *key) +{ + int err; + unsigned char flags[1]; + unsigned long key_size; + + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + LTC_ARGCHK(key != NULL); + + /* type valid? */ + if (key->type != PK_PRIVATE && type == PK_PRIVATE) { + return CRYPT_PK_TYPE_MISMATCH; + } + + if (is_valid_idx(key->idx) == 0) { + return CRYPT_INVALID_ARG; + } + + /* we store the NIST byte size */ + key_size = sets[key->idx].size; + + if (type == PK_PRIVATE) { + flags[0] = 1; + err = der_encode_sequence_multi(out, outlen, + LTC_ASN1_BIT_STRING, 1UL, flags, + LTC_ASN1_SHORT_INTEGER, 1UL, &key_size, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.x, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.y, + LTC_ASN1_INTEGER, 1UL, &key->k, + LTC_ASN1_EOL, 0UL, NULL); + } else { + flags[0] = 0; + err = der_encode_sequence_multi(out, outlen, + LTC_ASN1_BIT_STRING, 1UL, flags, + LTC_ASN1_SHORT_INTEGER, 1UL, &key_size, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.x, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.y, + LTC_ASN1_EOL, 0UL, NULL); + } + + return err; +} + +/** + Import an ECC key from a binary packet + @param in The packet to import + @param inlen The length of the packet + @param key [out] The destination of the import + @return CRYPT_OK if successful, upon error all allocated memory will be freed +*/ +int ecc_import(const unsigned char *in, unsigned long inlen, ecc_key *key) +{ + unsigned long key_size; + unsigned char flags[1]; + int err; + + LTC_ARGCHK(in != NULL); + LTC_ARGCHK(key != NULL); + + /* init key */ + if (mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL) != MP_OKAY) { + return CRYPT_MEM; + } + + /* find out what type of key it is */ + if ((err = der_decode_sequence_multi(in, inlen, + LTC_ASN1_BIT_STRING, 1UL, &flags, + LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { + goto error; + } + + + if (flags[0] == 1) { + /* private key */ + key->type = PK_PRIVATE; + if ((err = der_decode_sequence_multi(in, inlen, + LTC_ASN1_BIT_STRING, 1UL, flags, + LTC_ASN1_SHORT_INTEGER, 1UL, &key_size, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.x, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.y, + LTC_ASN1_INTEGER, 1UL, &key->k, + LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { + goto error; + } + } else { + /* public key */ + /* private key */ + key->type = PK_PUBLIC; + if ((err = der_decode_sequence_multi(in, inlen, + LTC_ASN1_BIT_STRING, 1UL, flags, + LTC_ASN1_SHORT_INTEGER, 1UL, &key_size, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.x, + LTC_ASN1_INTEGER, 1UL, &key->pubkey.y, + LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) { + goto error; + } + } + + /* find the idx */ + for (key->idx = 0; sets[key->idx].size && (unsigned long)sets[key->idx].size != key_size; ++key->idx); + if (sets[key->idx].size == 0) { + err = CRYPT_INVALID_PACKET; + goto error; + } + + /* set z */ + mp_set(&key->pubkey.z, 1); + + /* we're good */ + return CRYPT_OK; +error: + mp_clear_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, NULL); + return err; +} + +/** + Create an ECC shared secret between two keys + @param private_key The private ECC key + @param public_key The public key + @param out [out] Destination of the shared secret (Conforms to EC-DH from ANSI X9.63) + @param outlen [in/out] The max size and resulting size of the shared secret + @return CRYPT_OK if successful +*/ +int ecc_shared_secret(ecc_key *private_key, ecc_key *public_key, + unsigned char *out, unsigned long *outlen) +{ + unsigned long x; + ecc_point *result; + mp_int prime; + int err; + + LTC_ARGCHK(private_key != NULL); + LTC_ARGCHK(public_key != NULL); + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(outlen != NULL); + + /* type valid? */ + if (private_key->type != PK_PRIVATE) { + return CRYPT_PK_NOT_PRIVATE; + } + + if (is_valid_idx(private_key->idx) == 0) { + return CRYPT_INVALID_ARG; + } + + if (private_key->idx != public_key->idx) { + return CRYPT_PK_TYPE_MISMATCH; + } + + /* make new point */ + result = new_point(); + if (result == NULL) { + return CRYPT_MEM; + } + + if ((err = mp_init(&prime)) != MP_OKAY) { + del_point(result); + return mpi_to_ltc_error(err); + } + + if ((err = mp_read_radix(&prime, (char *)sets[private_key->idx].prime, 64)) != MP_OKAY) { goto error; } + if ((err = ecc_mulmod(&private_key->k, &public_key->pubkey, result, &prime, 1)) != CRYPT_OK) { goto done1; } + + x = (unsigned long)mp_unsigned_bin_size(&prime); + if (*outlen < x) { + err = CRYPT_BUFFER_OVERFLOW; + goto done1; + } + zeromem(out, x); + if ((err = mp_to_unsigned_bin(&result->x, out + (x - mp_unsigned_bin_size(&result->x)))) != MP_OKAY) { goto error; } + + err = CRYPT_OK; + *outlen = x; + goto done1; +error: + err = mpi_to_ltc_error(err); +done1: + mp_clear(&prime); + del_point(result); + return err; +} + +/** + Get the size of an ECC key + @param key The key to get the size of + @return The size (octets) of the key or INT_MAX on error +*/ +int ecc_get_size(ecc_key *key) +{ + LTC_ARGCHK(key != NULL); + if (is_valid_idx(key->idx)) + return sets[key->idx].size; + else + return INT_MAX; /* large value known to cause it to fail when passed to ecc_make_key() */ +} + +#include "ecc_sys.c" + +#endif + + + +/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc.c,v $ */ +/* $Revision: 1.20 $ */ +/* $Date: 2005/06/14 20:42:28 $ */ |