--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/ecc/ecc_encrypt_key.c	Thu Jan 11 02:41:05 2007 +0000
@@ -0,0 +1,136 @@
+/* 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.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 $ */
+