--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/ecc/ecc.c	Sat Mar 25 12:59:58 2006 +0000
@@ -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, [email protected], 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 $ */