/* 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_encrypt_key.c  ECC Crypto, Tom St Denis*/  #ifdef MECC/**  Encrypt a symmetric key with ECC   @param in         The symmetric key you want to encrypt  @param inlen      The length of the key to encrypt (octets)  @param out        [out] The destination for the ciphertext  @param outlen     [in/out] The max size and resulting size of the ciphertext  @param prng       An active PRNG state  @param wprng      The index of the PRNG you wish to use   @param hash       The index of the hash you want to use   @param key        The ECC key you want to encrypt to  @return CRYPT_OK if successful*/int ecc_encrypt_key(const unsigned char *in,   unsigned long inlen,                          unsigned char *out,  unsigned long *outlen,                           prng_state *prng, int wprng, int hash,                           ecc_key *key){    unsigned char *pub_expt, *ecc_shared, *skey;    ecc_key        pubkey;    unsigned long  x, y, pubkeysize;    int            err;    LTC_ARGCHK(in      != NULL);    LTC_ARGCHK(out     != NULL);    LTC_ARGCHK(outlen  != NULL);    LTC_ARGCHK(key     != NULL);    /* check that wprng/cipher/hash are not invalid */    if ((err = prng_is_valid(wprng)) != CRYPT_OK) {       return err;    }    if ((err = hash_is_valid(hash)) != CRYPT_OK) {       return err;    }    if (inlen > hash_descriptor[hash].hashsize) {       return CRYPT_INVALID_HASH;    }    /* make a random key and export the public copy */    if ((err = ecc_make_key_ex(prng, wprng, &pubkey, key->dp)) != CRYPT_OK) {       return err;    }    pub_expt   = XMALLOC(ECC_BUF_SIZE);    ecc_shared = XMALLOC(ECC_BUF_SIZE);    skey       = XMALLOC(MAXBLOCKSIZE);    if (pub_expt == NULL || ecc_shared == NULL || skey == NULL) {       if (pub_expt != NULL) {          XFREE(pub_expt);       }       if (ecc_shared != NULL) {          XFREE(ecc_shared);       }       if (skey != NULL) {          XFREE(skey);       }       ecc_free(&pubkey);       return CRYPT_MEM;    }    pubkeysize = ECC_BUF_SIZE;    if ((err = ecc_export(pub_expt, &pubkeysize, PK_PUBLIC, &pubkey)) != CRYPT_OK) {       ecc_free(&pubkey);       goto LBL_ERR;    }        /* make random key */    x        = ECC_BUF_SIZE;    if ((err = ecc_shared_secret(&pubkey, key, ecc_shared, &x)) != CRYPT_OK) {       ecc_free(&pubkey);       goto LBL_ERR;    }    ecc_free(&pubkey);    y = MAXBLOCKSIZE;    if ((err = hash_memory(hash, ecc_shared, x, skey, &y)) != CRYPT_OK) {       goto LBL_ERR;    }        /* Encrypt key */    for (x = 0; x < inlen; x++) {      skey[x] ^= in[x];    }    err = der_encode_sequence_multi(out, outlen,                                    LTC_ASN1_OBJECT_IDENTIFIER,  hash_descriptor[hash].OIDlen,   hash_descriptor[hash].OID,                                    LTC_ASN1_OCTET_STRING,       pubkeysize,                     pub_expt,                                    LTC_ASN1_OCTET_STRING,       inlen,                          skey,                                    LTC_ASN1_EOL,                0UL,                            NULL);LBL_ERR:#ifdef LTC_CLEAN_STACK    /* clean up */    zeromem(pub_expt,   ECC_BUF_SIZE);    zeromem(ecc_shared, ECC_BUF_SIZE);    zeromem(skey,       MAXBLOCKSIZE);#endif    XFREE(skey);    XFREE(ecc_shared);    XFREE(pub_expt);    return err;}#endif/* $Source: /cvs/libtom/libtomcrypt/src/pk/ecc/ecc_encrypt_key.c,v $ *//* $Revision: 1.4 $ *//* $Date: 2006/11/21 00:10:18 $ */