/* 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.com *//* 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_make_key.c  ECC Crypto, Tom St Denis*/  #ifdef MECC/**  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;   /* find key size */   for (x = 0; (keysize > ltc_ecc_sets[x].size) && (ltc_ecc_sets[x].size != 0); x++);   keysize = ltc_ecc_sets[x].size;   if (keysize > ECC_MAXSIZE || ltc_ecc_sets[x].size == 0) {      return CRYPT_INVALID_KEYSIZE;   }   err = ecc_make_key_ex(prng, wprng, key, &ltc_ecc_sets[x]);   key->idx = x;   return err;}int ecc_make_key_ex(prng_state *prng, int wprng, ecc_key *key, const ltc_ecc_set_type *dp){   int            err;   ecc_point     *base;   void          *prime;   unsigned char *buf;   int            keysize;   LTC_ARGCHK(key         != NULL);   LTC_ARGCHK(ltc_mp.name != NULL);   LTC_ARGCHK(dp          != NULL);   /* good prng? */   if ((err = prng_is_valid(wprng)) != CRYPT_OK) {      return err;   }   key->idx = -1;   key->dp  = dp;   keysize  = dp->size;   /* 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 ERR_BUF;   }   /* setup the key variables */   if ((err = mp_init_multi(&key->pubkey.x, &key->pubkey.y, &key->pubkey.z, &key->k, &prime, NULL)) != CRYPT_OK) {      goto ERR_BUF;   }   base = ltc_ecc_new_point();   if (base == NULL) {      err = CRYPT_MEM;      goto errkey;   }   /* read in the specs for this key */   if ((err = mp_read_radix(prime,   (char *)key->dp->prime, 16)) != CRYPT_OK)                  { goto errkey; }   if ((err = mp_read_radix(base->x, (char *)key->dp->Gx, 16)) != CRYPT_OK)                     { goto errkey; }   if ((err = mp_read_radix(base->y, (char *)key->dp->Gy, 16)) != CRYPT_OK)                     { goto errkey; }   if ((err = mp_set(base->z, 1)) != CRYPT_OK)                                                  { goto errkey; }   if ((err = mp_read_unsigned_bin(key->k, (unsigned char *)buf, keysize)) != CRYPT_OK)         { goto errkey; }   /* make the public key */   if ((err = ltc_mp.ecc_ptmul(key->k, base, &key->pubkey, prime, 1)) != CRYPT_OK)              { goto errkey; }   key->type = PK_PRIVATE;   /* free up ram */   err = CRYPT_OK;   goto cleanup;errkey:   mp_clear_multi(key->pubkey.x, key->pubkey.y, key->pubkey.z, key->k, NULL);cleanup:   ltc_ecc_del_point(base);   mp_clear(prime);ERR_BUF:#ifdef LTC_CLEAN_STACK   zeromem(buf, ECC_MAXSIZE);#endif   XFREE(buf);   return err;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_make_key.c,v $ *//* $Revision: 1.9 $ *//* $Date: 2006/12/04 02:50:11 $ */