path: root/lib/crypto/c_src/crypto.c

/* 
 * %CopyrightBegin%
 *
 * Copyright Ericsson AB 2010. All Rights Reserved.
 *
 * The contents of this file are subject to the Erlang Public License,
 * Version 1.1, (the "License"); you may not use this file except in
 * compliance with the License. You should have received a copy of the
 * Erlang Public License along with this software. If not, it can be
 * retrieved online at http://www.erlang.org/.
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * %CopyrightEnd%
 */

/*
 * Purpose:  Dynamically loadable NIF library for cryptography. 
 * Based on OpenSSL. 
 */

#ifdef __WIN32__
    #include <windows.h>
#endif

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include "erl_nif.h"

#define OPENSSL_THREAD_DEFINES
#include <openssl/opensslconf.h>

#include <openssl/crypto.h>
#include <openssl/des.h>
/* #include <openssl/idea.h> This is not supported on the openssl OTP requires */
#include <openssl/dsa.h>
#include <openssl/rsa.h>
#include <openssl/aes.h>
#include <openssl/md5.h>
#include <openssl/md4.h>
#include <openssl/sha.h>
#include <openssl/bn.h>
#include <openssl/objects.h>
#include <openssl/rc4.h>
#include <openssl/rc2.h>
#include <openssl/blowfish.h>
#include <openssl/rand.h>

#ifdef VALGRIND
    #  include <valgrind/memcheck.h>

/* libcrypto mixes supplied buffer contents into its entropy pool,
   which makes valgrind complain about the use of uninitialized data.
   We use this valgrind "request" to make sure that no such seemingly
   undefined data is returned.
*/
    #  define ERL_VALGRIND_MAKE_MEM_DEFINED(ptr,size) \
    VALGRIND_MAKE_MEM_DEFINED(ptr,size)

    #  define ERL_VALGRIND_ASSERT_MEM_DEFINED(ptr,size) \
    ((void) ((VALGRIND_CHECK_MEM_IS_DEFINED(ptr,size) == 0) ? 1 : \
    (fprintf(stderr,"\r\n####### VALGRIND_ASSSERT(%p,%ld) failed at %s:%d\r\n",\
	(ptr),(long)(size), __FILE__, __LINE__), abort(), 0)))
#else
    #  define ERL_VALGRIND_MAKE_MEM_DEFINED(ptr,size)
    #  define ERL_VALGRIND_ASSERT_MEM_DEFINED(ptr,size)
#endif

#ifdef DEBUG
    #  define ASSERT(e) \
    ((void) ((e) ? 1 : (fprintf(stderr,"Assert '%s' failed at %s:%d\n",\
				#e, __FILE__, __LINE__), abort(), 0)))
#else
    #  define ASSERT(e) ((void) 1)
#endif

#ifdef __GNUC__
    #  define INLINE __inline__
#elif defined(__WIN32__)
    #  define INLINE __forceinline
#else
    #  define INLINE
#endif


#define get_int32(s) ((((unsigned char*) (s))[0] << 24) | \
                      (((unsigned char*) (s))[1] << 16) | \
                      (((unsigned char*) (s))[2] << 8)  | \
                      (((unsigned char*) (s))[3]))

#define put_int32(s,i) \
{ (s)[0] = (char)(((i) >> 24) & 0xff);\
  (s)[1] = (char)(((i) >> 16) & 0xff);\
  (s)[2] = (char)(((i) >> 8) & 0xff);\
  (s)[3] = (char)((i) & 0xff);\
}

/* NIF interface declarations */
static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info);
static int reload(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info);
static int upgrade(ErlNifEnv* env, void** priv_data, void** old_priv_data, ERL_NIF_TERM load_info);
static void unload(ErlNifEnv* env, void* priv_data);

/* The NIFs: */
static ERL_NIF_TERM info_lib(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md5(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md5_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md5_update(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md5_final(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM sha(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM sha_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM sha_update(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM sha_final(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md4(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md4_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md4_update(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md4_final(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM md5_mac_n(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM sha_mac_n(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM des_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM des_ecb_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM des_ede3_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM aes_cfb_128_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rand_bytes_1(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rand_bytes_3(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rand_uniform_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM mod_exp_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM dss_verify(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rsa_verify(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM aes_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM exor(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rc4_encrypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rc4_set_key(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rc4_encrypt_with_state(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rc2_40_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rsa_sign_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM dss_sign_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rsa_public_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM rsa_private_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM dh_generate_parameters_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM dh_check(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM dh_generate_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM dh_compute_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM bf_cfb64_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM bf_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM bf_ecb_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
static ERL_NIF_TERM blowfish_ofb64_encrypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);


/* openssl callbacks */
#ifdef OPENSSL_THREADS
static void locking_function(int mode, int n, const char *file, int line);
static unsigned long id_function(void);
static struct CRYPTO_dynlock_value* dyn_create_function(const char *file,
							int line);
static void dyn_lock_function(int mode, struct CRYPTO_dynlock_value* ptr,
			      const char *file, int line);
static void dyn_destroy_function(struct CRYPTO_dynlock_value *ptr,
				 const char *file, int line);
#endif /* OPENSSL_THREADS */

/* helpers */
static void hmac_md5(unsigned char *key, int klen,
		     unsigned char *dbuf, int dlen, 
		     unsigned char *hmacbuf);
static void hmac_sha1(unsigned char *key, int klen,
		      unsigned char *dbuf, int dlen, 
		      unsigned char *hmacbuf);

static int library_refc = 0; /* number of users of this dynamic library */

static ErlNifFunc nif_funcs[] = {
    {"info_lib", 0, info_lib},
    {"md5", 1, md5},
    {"md5_init", 0, md5_init},
    {"md5_update", 2, md5_update},
    {"md5_final", 1, md5_final},
    {"sha", 1, sha},
    {"sha_init", 0, sha_init},
    {"sha_update", 2, sha_update},
    {"sha_final", 1, sha_final},
    {"md4", 1, md4},
    {"md4_init", 0, md4_init},
    {"md4_update", 2, md4_update},
    {"md4_final", 1, md4_final},
    {"md5_mac_n", 3, md5_mac_n},
    {"sha_mac_n", 3, sha_mac_n},
    {"des_cbc_crypt", 4, des_cbc_crypt},
    {"des_ecb_crypt", 3, des_ecb_crypt},
    {"des_ede3_cbc_crypt", 6, des_ede3_cbc_crypt},
    {"aes_cfb_128_crypt", 4, aes_cfb_128_crypt},
    {"rand_bytes", 1, rand_bytes_1},
    {"rand_bytes", 3, rand_bytes_3},
    {"rand_uniform_nif", 2, rand_uniform_nif},
    {"mod_exp_nif", 3, mod_exp_nif},
    {"dss_verify", 4, dss_verify},
    {"rsa_verify", 4, rsa_verify},
    {"aes_cbc_crypt", 4, aes_cbc_crypt},
    {"exor", 2, exor},
    {"rc4_encrypt", 2, rc4_encrypt},
    {"rc4_set_key", 1, rc4_set_key},
    {"rc4_encrypt_with_state", 2, rc4_encrypt_with_state},
    {"rc2_40_cbc_crypt", 4, rc2_40_cbc_crypt},
    {"rsa_sign_nif", 3, rsa_sign_nif},
    {"dss_sign_nif", 3, dss_sign_nif},
    {"rsa_public_crypt", 4, rsa_public_crypt},
    {"rsa_private_crypt", 4, rsa_private_crypt},
    {"dh_generate_parameters_nif", 2, dh_generate_parameters_nif},
    {"dh_check", 1, dh_check},
    {"dh_generate_key_nif", 2, dh_generate_key_nif},
    {"dh_compute_key_nif", 3, dh_compute_key_nif},
    {"bf_cfb64_crypt", 4, bf_cfb64_crypt},
    {"bf_cbc_crypt", 4, bf_cbc_crypt},
    {"bf_ecb_crypt", 3, bf_ecb_crypt},
    {"blowfish_ofb64_encrypt", 3, blowfish_ofb64_encrypt}
};

ERL_NIF_INIT(crypto,nif_funcs,load,reload,upgrade,unload)


#define MD5_CTX_LEN     (sizeof(MD5_CTX))
#define MD5_LEN         16
#define MD5_LEN_96      12
#define MD4_CTX_LEN     (sizeof(MD4_CTX))
#define MD4_LEN         16
#define SHA_CTX_LEN     (sizeof(SHA_CTX))
#define SHA_LEN         20
#define SHA_LEN_96      12
#define HMAC_INT_LEN    64

#define HMAC_IPAD       0x36
#define HMAC_OPAD       0x5c


static ErlNifRWLock** lock_vec = NULL; /* Static locks used by openssl */
static ERL_NIF_TERM atom_true;
static ERL_NIF_TERM atom_false;
static ERL_NIF_TERM atom_sha;
static ERL_NIF_TERM atom_md5;
static ERL_NIF_TERM atom_error;
static ERL_NIF_TERM atom_rsa_pkcs1_padding;
static ERL_NIF_TERM atom_rsa_pkcs1_oaep_padding;
static ERL_NIF_TERM atom_rsa_no_padding;
static ERL_NIF_TERM atom_undefined;

static ERL_NIF_TERM atom_ok;
static ERL_NIF_TERM atom_not_prime;
static ERL_NIF_TERM atom_not_strong_prime;
static ERL_NIF_TERM atom_unable_to_check_generator;
static ERL_NIF_TERM atom_not_suitable_generator;
static ERL_NIF_TERM atom_check_failed;
static ERL_NIF_TERM atom_unknown;
static ERL_NIF_TERM atom_none;


static int is_ok_load_info(ErlNifEnv* env, ERL_NIF_TERM load_info)
{
    int i;
    return enif_get_int(env,load_info,&i) && i == 101;
}
static void* crypto_alloc(size_t size)
{   
    return enif_alloc(size);
}
static void* crypto_realloc(void* ptr, size_t size)
{
    return enif_realloc(ptr, size);
}   
static void crypto_free(void* ptr)
{   
    enif_free(ptr); 
}

static int load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
{
    ErlNifSysInfo sys_info;
    CRYPTO_set_mem_functions(crypto_alloc, crypto_realloc, crypto_free);

    if (!is_ok_load_info(env, load_info)) {
	return -1;
    }

#ifdef OPENSSL_THREADS
    enif_system_info(&sys_info, sizeof(sys_info));

    if (sys_info.scheduler_threads > 1) {
	int i;
	lock_vec = enif_alloc(CRYPTO_num_locks()*sizeof(*lock_vec));
	if (lock_vec==NULL) return -1;
	memset(lock_vec,0,CRYPTO_num_locks()*sizeof(*lock_vec));

	for (i=CRYPTO_num_locks()-1; i>=0; --i) {
	    lock_vec[i] = enif_rwlock_create("crypto_stat");
	    if (lock_vec[i]==NULL) return -1;
	}
	CRYPTO_set_locking_callback(locking_function);
	CRYPTO_set_id_callback(id_function);
	CRYPTO_set_dynlock_create_callback(dyn_create_function);
	CRYPTO_set_dynlock_lock_callback(dyn_lock_function);
	CRYPTO_set_dynlock_destroy_callback(dyn_destroy_function);
    }
    /* else no need for locks */
#endif /* OPENSSL_THREADS */

    atom_true = enif_make_atom(env,"true");
    atom_false = enif_make_atom(env,"false");
    atom_sha = enif_make_atom(env,"sha");
    atom_md5 = enif_make_atom(env,"md5");
    atom_error = enif_make_atom(env,"error");
    atom_rsa_pkcs1_padding = enif_make_atom(env,"rsa_pkcs1_padding");
    atom_rsa_pkcs1_oaep_padding = enif_make_atom(env,"rsa_pkcs1_oaep_padding");
    atom_rsa_no_padding = enif_make_atom(env,"rsa_no_padding");
    atom_undefined = enif_make_atom(env,"undefined");
    atom_ok = enif_make_atom(env,"ok");
    atom_not_prime = enif_make_atom(env,"not_prime");
    atom_not_strong_prime = enif_make_atom(env,"not_strong_prime");
    atom_unable_to_check_generator = enif_make_atom(env,"unable_to_check_generator");
    atom_not_suitable_generator = enif_make_atom(env,"not_suitable_generator");
    atom_check_failed = enif_make_atom(env,"check_failed");
    atom_unknown = enif_make_atom(env,"unknown");
    atom_none = enif_make_atom(env,"none");

    *priv_data = NULL;
    library_refc++;
    return 0;
}

static int reload(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
{   
    if (*priv_data != NULL) {
	return -1; /* Don't know how to do that */
    }
    if (library_refc == 0) {
	/* No support for real library upgrade. The tricky thing is to know
	   when to (re)set the callbacks for allocation and locking. */
	return -2;
    }
    if (!is_ok_load_info(env, load_info)) {
	return -1;
    }
    return 0;    
}

static int upgrade(ErlNifEnv* env, void** priv_data, void** old_priv_data,
		   ERL_NIF_TERM load_info)
{
    int i;
    if (*old_priv_data != NULL) {
	return -1; /* Don't know how to do that */
    }
    i = reload(env,priv_data,load_info);
    if (i != 0) {
	return i;
    }
    library_refc++;
    return 0;
}

static void unload(ErlNifEnv* env, void* priv_data)
{
    if (--library_refc <= 0) {
	CRYPTO_cleanup_all_ex_data();

	if (lock_vec != NULL) {
	    int i;
	    for (i=CRYPTO_num_locks()-1; i>=0; --i) {
		if (lock_vec[i] != NULL) {
		    enif_rwlock_destroy(lock_vec[i]);
		}
	    }
	    enif_free(lock_vec);
	}
    }
    /*else NIF library still used by other (new) module code */
}

static ERL_NIF_TERM info_lib(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{
    /* [{<<"OpenSSL">>,9470143,<<"OpenSSL 0.9.8k 25 Mar 2009">>}] */

    static const char libname[] = "OpenSSL";
    unsigned name_sz = strlen(libname);
    const char* ver = SSLeay_version(SSLEAY_VERSION);
    unsigned ver_sz = strlen(ver);
    ERL_NIF_TERM name_term, ver_term;

    memcpy(enif_make_new_binary(env, name_sz, &name_term), libname, name_sz);    
    memcpy(enif_make_new_binary(env, ver_sz, &ver_term), ver, ver_sz);

    return enif_make_list1(env, enif_make_tuple3(env, name_term,
						 enif_make_int(env, SSLeay()),
						 ver_term));
}

static ERL_NIF_TERM md5(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Data) */
    ErlNifBinary ibin;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &ibin)) {
	return enif_make_badarg(env);
    }
    MD5((unsigned char *) ibin.data, ibin.size,
	enif_make_new_binary(env,MD5_LEN, &ret));
    return ret;
}
static ERL_NIF_TERM md5_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* () */   
    ERL_NIF_TERM ret;
    MD5_Init((MD5_CTX *) enif_make_new_binary(env, MD5_CTX_LEN, &ret));
    return ret;
}
static ERL_NIF_TERM md5_update(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context, Data) */
    MD5_CTX* new_ctx;
    ErlNifBinary ctx_bin, data_bin;
    ERL_NIF_TERM ret;
    if (!enif_inspect_binary(env, argv[0], &ctx_bin)
	|| ctx_bin.size != MD5_CTX_LEN
	|| !enif_inspect_iolist_as_binary(env, argv[1], &data_bin)) {
	return enif_make_badarg(env);
    }
    new_ctx = (MD5_CTX*) enif_make_new_binary(env,MD5_CTX_LEN, &ret);
    memcpy(new_ctx, ctx_bin.data, MD5_CTX_LEN);
    MD5_Update(new_ctx, data_bin.data, data_bin.size);
    return ret;
}
static ERL_NIF_TERM md5_final(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context) */
    ErlNifBinary ctx_bin;
    MD5_CTX ctx_clone; 
    ERL_NIF_TERM ret;    
    if (!enif_inspect_binary(env, argv[0], &ctx_bin) || ctx_bin.size != MD5_CTX_LEN) {
	return enif_make_badarg(env);
    }
    memcpy(&ctx_clone, ctx_bin.data, MD5_CTX_LEN); /* writable */
    MD5_Final(enif_make_new_binary(env, MD5_LEN, &ret), &ctx_clone);
    return ret;
}

static ERL_NIF_TERM sha(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Data) */    
    ErlNifBinary ibin;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &ibin)) {
	return enif_make_badarg(env);
    }
    SHA1((unsigned char *) ibin.data, ibin.size,
	 enif_make_new_binary(env,SHA_LEN, &ret));
    return ret;
}
static ERL_NIF_TERM sha_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* () */   
    ERL_NIF_TERM ret;
    SHA1_Init((SHA_CTX *) enif_make_new_binary(env, SHA_CTX_LEN, &ret));
    return ret;
}
static ERL_NIF_TERM sha_update(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context, Data) */
    SHA_CTX* new_ctx;
    ErlNifBinary ctx_bin, data_bin;
    ERL_NIF_TERM ret;
    if (!enif_inspect_binary(env, argv[0], &ctx_bin) || ctx_bin.size != SHA_CTX_LEN
	|| !enif_inspect_iolist_as_binary(env, argv[1], &data_bin)) {
	return enif_make_badarg(env);
    }
    new_ctx = (SHA_CTX*) enif_make_new_binary(env,SHA_CTX_LEN, &ret);
    memcpy(new_ctx, ctx_bin.data, SHA_CTX_LEN);
    SHA1_Update(new_ctx, data_bin.data, data_bin.size);
    return ret;
}
static ERL_NIF_TERM sha_final(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context) */
    ErlNifBinary ctx_bin;
    SHA_CTX ctx_clone;
    ERL_NIF_TERM ret;
    if (!enif_inspect_binary(env, argv[0], &ctx_bin) || ctx_bin.size != SHA_CTX_LEN) {
	return enif_make_badarg(env);
    }
    memcpy(&ctx_clone, ctx_bin.data, SHA_CTX_LEN); /* writable */
    SHA1_Final(enif_make_new_binary(env, SHA_LEN, &ret), &ctx_clone);    
    return ret;
}

static ERL_NIF_TERM md4(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Data) */    
    ErlNifBinary ibin;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &ibin)) {
	return enif_make_badarg(env);
    }
    MD4((unsigned char *) ibin.data, ibin.size,
	enif_make_new_binary(env,MD4_LEN, &ret));
    return ret;
}
static ERL_NIF_TERM md4_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* () */   
    ERL_NIF_TERM ret;
    MD4_Init((MD4_CTX *) enif_make_new_binary(env, MD4_CTX_LEN, &ret));
    return ret;
}
static ERL_NIF_TERM md4_update(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context, Data) */
    MD4_CTX* new_ctx;
    ErlNifBinary ctx_bin, data_bin;
    ERL_NIF_TERM ret;
    if (!enif_inspect_binary(env, argv[0], &ctx_bin) || ctx_bin.size != MD4_CTX_LEN
	|| !enif_inspect_iolist_as_binary(env, argv[1], &data_bin)) {
	return enif_make_badarg(env);
    }
    new_ctx = (MD4_CTX*) enif_make_new_binary(env,MD4_CTX_LEN, &ret);
    memcpy(new_ctx, ctx_bin.data, MD4_CTX_LEN);
    MD4_Update(new_ctx, data_bin.data, data_bin.size);
    return ret;
}
static ERL_NIF_TERM md4_final(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Context) */
    ErlNifBinary ctx_bin;
    MD4_CTX ctx_clone;
    ERL_NIF_TERM ret;    
    if (!enif_inspect_binary(env, argv[0], &ctx_bin) || ctx_bin.size != MD4_CTX_LEN) {
	return enif_make_badarg(env);
    }
    memcpy(&ctx_clone, ctx_bin.data, MD4_CTX_LEN); /* writable */
    MD4_Final(enif_make_new_binary(env, MD4_LEN, &ret), &ctx_clone);    
    return ret;
}

static ERL_NIF_TERM md5_mac_n(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, Data, MacSize) */
    unsigned char hmacbuf[SHA_DIGEST_LENGTH];
    ErlNifBinary key, data;
    unsigned mac_sz;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key)
	|| !enif_inspect_iolist_as_binary(env, argv[1], &data)
	|| !enif_get_uint(env,argv[2],&mac_sz) || mac_sz > MD5_LEN) {
	return enif_make_badarg(env);
    }
    hmac_md5(key.data, key.size, data.data, data.size, hmacbuf);
    memcpy(enif_make_new_binary(env, mac_sz, &ret), hmacbuf, mac_sz);
    return ret;
}

static ERL_NIF_TERM sha_mac_n(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, Data, MacSize) */
    unsigned char hmacbuf[SHA_DIGEST_LENGTH];
    ErlNifBinary key, data;
    unsigned mac_sz;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key)
	|| !enif_inspect_iolist_as_binary(env, argv[1], &data)
	|| !enif_get_uint(env,argv[2],&mac_sz) || mac_sz > SHA_LEN) {
	return enif_make_badarg(env);
    }
    hmac_sha1(key.data, key.size, data.data, data.size, hmacbuf);
    memcpy(enif_make_new_binary(env, mac_sz, &ret),
	   hmacbuf, mac_sz);
    return ret;
}

static ERL_NIF_TERM des_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, Ivec, Text, IsEncrypt) */    
    ErlNifBinary key, ivec, text;
    DES_key_schedule schedule;
    DES_cblock ivec_clone; /* writable copy */
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key) || key.size != 8
	|| !enif_inspect_binary(env, argv[1], &ivec) || ivec.size != 8
	|| !enif_inspect_iolist_as_binary(env, argv[2], &text)
	|| text.size % 8 != 0) {
	return enif_make_badarg(env);
    }
    memcpy(&ivec_clone, ivec.data, 8);
    DES_set_key((const_DES_cblock*)key.data, &schedule);
    DES_ncbc_encrypt(text.data, enif_make_new_binary(env, text.size, &ret),
		     text.size, &schedule, &ivec_clone, (argv[3] == atom_true));
    return ret;
}

static ERL_NIF_TERM des_ecb_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, Text/Cipher, IsEncrypt) */
    ErlNifBinary key, text;
    DES_key_schedule schedule;
    ERL_NIF_TERM ret;
    if (!enif_inspect_iolist_as_binary(env, argv[0], &key) || key.size != 8 ||
	!enif_inspect_iolist_as_binary(env, argv[1], &text) || text.size != 8) {
	return enif_make_badarg(env);
    }
    DES_set_key((const_DES_cblock*)key.data, &schedule);
    DES_ecb_encrypt((const_DES_cblock*)text.data,
		    (DES_cblock*)enif_make_new_binary(env, 8, &ret),
		    &schedule, (argv[2] == atom_true));
    return ret;
}

static ERL_NIF_TERM des_ede3_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key1, Key2, Key3, IVec, Text/Cipher, IsEncrypt) */    
    ErlNifBinary key1, key2, key3, ivec, text;
    DES_key_schedule schedule1, schedule2, schedule3;
    DES_cblock ivec_clone; /* writable copy */
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key1) || key1.size != 8
	|| !enif_inspect_iolist_as_binary(env, argv[1], &key2) || key2.size != 8
	|| !enif_inspect_iolist_as_binary(env, argv[2], &key3) || key3.size != 8
	|| !enif_inspect_binary(env, argv[3], &ivec) || ivec.size != 8
	|| !enif_inspect_iolist_as_binary(env, argv[4], &text)
	|| text.size % 8 != 0) {
	return enif_make_badarg(env);
    }

    memcpy(&ivec_clone, ivec.data, 8);
    DES_set_key((const_DES_cblock*)key1.data, &schedule1);
    DES_set_key((const_DES_cblock*)key2.data, &schedule2);
    DES_set_key((const_DES_cblock*)key3.data, &schedule3);
    DES_ede3_cbc_encrypt(text.data, enif_make_new_binary(env,text.size,&ret), 
			 text.size, &schedule1, &schedule2, &schedule3,
			 &ivec_clone, (argv[5] == atom_true));
    return ret;
}

static ERL_NIF_TERM aes_cfb_128_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, IVec, Data, IsEncrypt) */    
    ErlNifBinary key, ivec, text;
    AES_KEY aes_key;
    unsigned char ivec_clone[16]; /* writable copy */
    int new_ivlen = 0;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key) || key.size != 16
	|| !enif_inspect_binary(env, argv[1], &ivec) || ivec.size != 16
	|| !enif_inspect_iolist_as_binary(env, argv[2], &text)
	|| text.size % 16 != 0) {
	return enif_make_badarg(env);
    }

    memcpy(ivec_clone, ivec.data, 16);
    AES_set_encrypt_key(key.data, 128, &aes_key);
    AES_cfb128_encrypt((unsigned char *) text.data,
		       enif_make_new_binary(env, text.size, &ret), 
		       text.size, &aes_key, ivec_clone, &new_ivlen,
		       (argv[3] == atom_true));
    return ret;
}

static ERL_NIF_TERM rand_bytes_1(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Bytes) */     
    unsigned bytes;
    unsigned char* data;
    ERL_NIF_TERM ret;
    if (!enif_get_uint(env, argv[0], &bytes)) {
	return enif_make_badarg(env);
    }
    data = enif_make_new_binary(env, bytes, &ret);
    RAND_pseudo_bytes(data, bytes);
    ERL_VALGRIND_MAKE_MEM_DEFINED(data, bytes);
    return ret;
}
static ERL_NIF_TERM rand_bytes_3(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Bytes, TopMask, BottomMask) */    
    unsigned bytes;
    unsigned char* data;
    unsigned top_mask, bot_mask;
    ERL_NIF_TERM ret;
    if (!enif_get_uint(env, argv[0], &bytes)
	|| !enif_get_uint(env, argv[1], &top_mask)
	|| !enif_get_uint(env, argv[2], &bot_mask)) {
	return enif_make_badarg(env);
    }
    data = enif_make_new_binary(env, bytes, &ret);
    RAND_pseudo_bytes(data, bytes);
    ERL_VALGRIND_MAKE_MEM_DEFINED(data, bytes);
    if (bytes > 0) {
	data[bytes-1] |= top_mask;
	data[0] |= bot_mask;
    }
    return ret;
}

static int get_bn_from_mpint(ErlNifEnv* env, ERL_NIF_TERM term, BIGNUM** bnp)
{
    ErlNifBinary bin;
    int sz;
    if (!enif_inspect_binary(env,term,&bin)) {
	return 0;
    }
    ERL_VALGRIND_ASSERT_MEM_DEFINED(bin.data, bin.size);
    sz = bin.size - 4;
    if (sz < 0 || get_int32(bin.data) != sz) {
	return 0;
    }
    *bnp = BN_bin2bn(bin.data+4, sz, NULL);
    return 1;
}

static ERL_NIF_TERM rand_uniform_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Lo,Hi) */
    BIGNUM *bn_from = NULL, *bn_to, *bn_rand;
    unsigned char* data;
    unsigned dlen;
    ERL_NIF_TERM ret;
    if (!get_bn_from_mpint(env, argv[0], &bn_from)
	|| !get_bn_from_mpint(env, argv[1], &bn_rand)) {
	if (bn_from) BN_free(bn_from);
	return enif_make_badarg(env);
    }

    bn_to = BN_new();
    BN_sub(bn_to, bn_rand, bn_from);
    BN_pseudo_rand_range(bn_rand, bn_to);      
    BN_add(bn_rand, bn_rand, bn_from);
    dlen = BN_num_bytes(bn_rand);
    data = enif_make_new_binary(env, dlen+4, &ret);
    put_int32(data, dlen);
    BN_bn2bin(bn_rand, data+4);
    ERL_VALGRIND_MAKE_MEM_DEFINED(data+4, dlen);
    BN_free(bn_rand);
    BN_free(bn_from);
    BN_free(bn_to);
    return ret;
}

static ERL_NIF_TERM mod_exp_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Base,Exponent,Modulo) */
    BIGNUM *bn_base=NULL, *bn_exponent=NULL, *bn_modulo, *bn_result;
    BN_CTX *bn_ctx;
    unsigned char* ptr;
    unsigned dlen;      
    ERL_NIF_TERM ret;

    if (!get_bn_from_mpint(env, argv[0], &bn_base)
	|| !get_bn_from_mpint(env, argv[1], &bn_exponent)
	|| !get_bn_from_mpint(env, argv[2], &bn_modulo)) {

	if (bn_base) BN_free(bn_base);
	if (bn_exponent) BN_free(bn_exponent);
	return enif_make_badarg(env);
    }
    bn_result = BN_new();
    bn_ctx = BN_CTX_new();
    BN_mod_exp(bn_result, bn_base, bn_exponent, bn_modulo, bn_ctx);
    dlen = BN_num_bytes(bn_result);
    ptr = enif_make_new_binary(env, dlen+4, &ret);
    put_int32(ptr, dlen);
    BN_bn2bin(bn_result, ptr+4);
    BN_free(bn_result);
    BN_CTX_free(bn_ctx);
    BN_free(bn_modulo);
    BN_free(bn_exponent);
    BN_free(bn_base);
    return ret;
}

static int inspect_mpint(ErlNifEnv* env, ERL_NIF_TERM term, ErlNifBinary* bin)
{    
    return enif_inspect_binary(env, term, bin) &&
    bin->size >= 4 && get_int32(bin->data) == bin->size-4;
}

static ERL_NIF_TERM dss_verify(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (DigestType,Data,Signature,Key=[P, Q, G, Y]) */
    ErlNifBinary data_bin, sign_bin;
    BIGNUM *dsa_p = NULL, *dsa_q = NULL, *dsa_g = NULL, *dsa_y = NULL;
    unsigned char hmacbuf[SHA_DIGEST_LENGTH];
    ERL_NIF_TERM head, tail;
    DSA *dsa;
    int i;

    if (!inspect_mpint(env, argv[2], &sign_bin)
	|| !enif_get_list_cell(env, argv[3], &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa_p)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa_q)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa_g)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa_y)
	|| !enif_is_empty_list(env,tail)) {
    badarg:
	if (dsa_p) BN_free(dsa_p);
	if (dsa_q) BN_free(dsa_q);
	if (dsa_g) BN_free(dsa_g);
	if (dsa_y) BN_free(dsa_y);
	return enif_make_badarg(env);
    }
    if (argv[0] == atom_sha && inspect_mpint(env, argv[1], &data_bin)) {
	SHA1(data_bin.data+4, data_bin.size-4, hmacbuf);
    }
    else if (argv[0] == atom_none && enif_inspect_binary(env, argv[1], &data_bin)
	     && data_bin.size == SHA_DIGEST_LENGTH) {
	memcpy(hmacbuf, data_bin.data, SHA_DIGEST_LENGTH);
    }
    else {
	goto badarg;
    }

    dsa = DSA_new();
    dsa->p = dsa_p;
    dsa->q = dsa_q;
    dsa->g = dsa_g;
    dsa->priv_key = NULL;
    dsa->pub_key = dsa_y;
    i =  DSA_verify(0, hmacbuf, SHA_DIGEST_LENGTH,
		    sign_bin.data+4, sign_bin.size-4, dsa);
    DSA_free(dsa);
    return(i > 0) ? atom_true : atom_false;
}

static ERL_NIF_TERM rsa_verify(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Type, Data, Signature, Key=[E,N]) */
    ErlNifBinary data_bin, sign_bin;
    unsigned char hmacbuf[SHA_DIGEST_LENGTH];
    ERL_NIF_TERM head, tail, ret;
    int i, is_sha;
    RSA* rsa = RSA_new();

    if (argv[0] == atom_sha) is_sha = 1;
    else if (argv[0] == atom_md5) is_sha = 0;
    else goto badarg;

    if (!inspect_mpint(env, argv[1], &data_bin)
	|| !inspect_mpint(env, argv[2], &sign_bin)
	|| !enif_get_list_cell(env, argv[3], &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->e)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->n)
	|| !enif_is_empty_list(env, tail)) {
    badarg:
	ret = enif_make_badarg(env);
    }
    else {
	if (is_sha) {
	    SHA1(data_bin.data+4, data_bin.size-4, hmacbuf);
	    i = RSA_verify(NID_sha1, hmacbuf, SHA_DIGEST_LENGTH,
			   sign_bin.data+4, sign_bin.size-4, rsa);
	}
	else {
	    MD5(data_bin.data+4, data_bin.size-4, hmacbuf);
	    i = RSA_verify(NID_md5, hmacbuf, MD5_DIGEST_LENGTH,
			   sign_bin.data+4, sign_bin.size-4, rsa);
	}
	ret = (i==1 ? atom_true : atom_false);
    }
    RSA_free(rsa);
    return ret;
}

static ERL_NIF_TERM aes_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, IVec, Data, IsEncrypt) */
    ErlNifBinary key_bin, ivec_bin, data_bin;
    AES_KEY aes_key;
    unsigned char ivec[16];
    int i;
    unsigned char* ret_ptr;
    ERL_NIF_TERM ret;    

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
	|| (key_bin.size != 16 && key_bin.size != 32)
	|| !enif_inspect_binary(env, argv[1], &ivec_bin)
	|| ivec_bin.size != 16
	|| !enif_inspect_iolist_as_binary(env, argv[2], &data_bin)
	|| data_bin.size % 16 != 0) {

	return enif_make_badarg(env);
    }

    if (argv[3] == atom_true) {
	i = AES_ENCRYPT;
	AES_set_encrypt_key(key_bin.data, key_bin.size*8, &aes_key);
    }
    else {
	i = AES_DECRYPT;
	AES_set_decrypt_key(key_bin.data, key_bin.size*8, &aes_key);
    }

    ret_ptr = enif_make_new_binary(env, data_bin.size, &ret);
    memcpy(ivec, ivec_bin.data, 16); /* writable copy */
    AES_cbc_encrypt(data_bin.data, ret_ptr, data_bin.size, &aes_key, ivec, i);
    return ret;
}

static ERL_NIF_TERM exor(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Data1, Data2) */
    ErlNifBinary d1, d2;
    unsigned char* ret_ptr;
    int i;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env,argv[0], &d1)
	|| !enif_inspect_iolist_as_binary(env,argv[1], &d2)
	|| d1.size != d2.size) {
	return enif_make_badarg(env);
    }
    ret_ptr = enif_make_new_binary(env, d1.size, &ret);

    for (i=0; i<d1.size; i++) {
	ret_ptr[i] = d1.data[i] ^ d2.data[i];
    }
    return ret;
}

static ERL_NIF_TERM rc4_encrypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, Data) */
    ErlNifBinary key, data;
    RC4_KEY rc4_key;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env,argv[0], &key)
	|| !enif_inspect_iolist_as_binary(env,argv[1], &data)) {
	return enif_make_badarg(env);
    }
    RC4_set_key(&rc4_key, key.size, key.data);
    RC4(&rc4_key, data.size, data.data,
	enif_make_new_binary(env, data.size, &ret));
    return ret;
}   

static ERL_NIF_TERM rc4_set_key(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key) */
    ErlNifBinary key;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env,argv[0], &key)) {
	return enif_make_badarg(env);
    }
    RC4_set_key((RC4_KEY*)enif_make_new_binary(env, sizeof(RC4_KEY), &ret),
		key.size, key.data);        
    return ret;
}

static ERL_NIF_TERM rc4_encrypt_with_state(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (State, Data) */

    ErlNifBinary state, data;
    RC4_KEY* rc4_key;
    ERL_NIF_TERM new_state, new_data;

    if (!enif_inspect_iolist_as_binary(env,argv[0], &state)
	|| state.size != sizeof(RC4_KEY)
	|| !enif_inspect_iolist_as_binary(env,argv[1], &data)) {
	return enif_make_badarg(env);
    }
    rc4_key = (RC4_KEY*)enif_make_new_binary(env, sizeof(RC4_KEY), &new_state);
    memcpy(rc4_key, state.data, sizeof(RC4_KEY));
    RC4(rc4_key, data.size, data.data,
	enif_make_new_binary(env, data.size, &new_data));

    return enif_make_tuple2(env,new_state,new_data);
}   

static ERL_NIF_TERM rc2_40_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key,IVec,Data,IsEncrypt) */
    ErlNifBinary key_bin, ivec_bin, data_bin;
    RC2_KEY rc2_key;
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
	|| key_bin.size != 5
	|| !enif_inspect_binary(env, argv[1], &ivec_bin)
	|| ivec_bin.size != 8
	|| !enif_inspect_iolist_as_binary(env, argv[2], &data_bin)) {

	return enif_make_badarg(env);
    }

    RC2_set_key(&rc2_key, 5, key_bin.data, 40);
    RC2_cbc_encrypt(data_bin.data,
		    enif_make_new_binary(env, data_bin.size, &ret), 
		    data_bin.size, &rc2_key,
		    ivec_bin.data,
		    (argv[3] == atom_true));

    return ret;
}   

static ERL_NIF_TERM rsa_sign_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Type,Data,Key=[E,N,D]) */
    ErlNifBinary data_bin, ret_bin;
    ERL_NIF_TERM head, tail;
    unsigned char hmacbuf[SHA_DIGEST_LENGTH];
    unsigned rsa_s_len;
    RSA *rsa = RSA_new();
    int i, is_sha;

    if (argv[0] == atom_sha) is_sha = 1;
    else if (argv[0] == atom_md5) is_sha = 0;
    else goto badarg;

    if (!inspect_mpint(env,argv[1],&data_bin)
	|| !enif_get_list_cell(env, argv[2], &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->e)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->n)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->d)
	|| !enif_is_empty_list(env,tail)) {
    badarg:
	RSA_free(rsa);
	return enif_make_badarg(env);
    }
    enif_alloc_binary(RSA_size(rsa), &ret_bin);
    if (is_sha) {
	SHA1(data_bin.data+4, data_bin.size-4, hmacbuf);
	ERL_VALGRIND_ASSERT_MEM_DEFINED(hmacbuf, SHA_DIGEST_LENGTH);
	i =  RSA_sign(NID_sha1, hmacbuf, SHA_DIGEST_LENGTH,
		      ret_bin.data, &rsa_s_len, rsa);
    }
    else {
	MD5(data_bin.data+4, data_bin.size-4, hmacbuf);
	ERL_VALGRIND_ASSERT_MEM_DEFINED(hmacbuf, MD5_DIGEST_LENGTH);
	i = RSA_sign(NID_md5, hmacbuf,MD5_DIGEST_LENGTH,
		     ret_bin.data, &rsa_s_len, rsa);     
    }
    RSA_free(rsa);
    if (i) {
	ERL_VALGRIND_MAKE_MEM_DEFINED(ret_bin.data, rsa_s_len);
	if (rsa_s_len != data_bin.size) {
	    enif_realloc_binary(&ret_bin, rsa_s_len);
	    ERL_VALGRIND_ASSERT_MEM_DEFINED(ret_bin.data, rsa_s_len);
	}
	return enif_make_binary(env,&ret_bin);
    }
    else {
	enif_release_binary(&ret_bin);
	return atom_error;
    }
}

static ERL_NIF_TERM dss_sign_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (DigesType, Data, Key=[P,Q,G,PrivKey]) */
    ErlNifBinary data_bin, ret_bin;
    ERL_NIF_TERM head, tail;
    unsigned char hmacbuf[SHA_DIGEST_LENGTH];
    unsigned int dsa_s_len;
    DSA* dsa = DSA_new();
    int i;

    dsa->pub_key  = NULL;
    if (!enif_get_list_cell(env, argv[2], &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa->p)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa->q)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa->g)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dsa->priv_key)
	|| !enif_is_empty_list(env,tail)) {
	goto badarg;	
    }
    if (argv[0] == atom_sha && inspect_mpint(env, argv[1], &data_bin)) {
	SHA1(data_bin.data+4, data_bin.size-4, hmacbuf);
    }
    else if (argv[0] == atom_none && enif_inspect_binary(env,argv[1],&data_bin) 
	     && data_bin.size == SHA_DIGEST_LENGTH) {
	memcpy(hmacbuf, data_bin.data, SHA_DIGEST_LENGTH);
    }
    else {
    badarg:
	DSA_free(dsa);
	return enif_make_badarg(env);
    }

    enif_alloc_binary(DSA_size(dsa), &ret_bin);
    i =  DSA_sign(NID_sha1, hmacbuf, SHA_DIGEST_LENGTH,
		  ret_bin.data, &dsa_s_len, dsa);
    DSA_free(dsa);
    if (i) {
	if (dsa_s_len != ret_bin.size) {
	    enif_realloc_binary(&ret_bin, dsa_s_len);
	}
	return enif_make_binary(env, &ret_bin);
    }
    else {
	return atom_error;
    }
}

static int rsa_pad(ERL_NIF_TERM term, int* padding)
{
    if (term == atom_rsa_pkcs1_padding) {
	*padding = RSA_PKCS1_PADDING;
    }
    else if (term == atom_rsa_pkcs1_oaep_padding) {
	*padding = RSA_PKCS1_OAEP_PADDING;
    }
    else if (term == atom_rsa_no_padding) {
	*padding = RSA_NO_PADDING;
    }
    else {
	return 0;
    }
    return 1;
}

static ERL_NIF_TERM rsa_public_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Data, PublKey=[E,N], Padding, IsEncrypt) */
    ErlNifBinary data_bin, ret_bin;
    ERL_NIF_TERM head, tail;
    int padding, i;
    RSA* rsa = RSA_new();

    if (!enif_inspect_binary(env, argv[0], &data_bin)
	|| !enif_get_list_cell(env, argv[1], &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->e)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->n)
	|| !enif_is_empty_list(env,tail)
	|| !rsa_pad(argv[2], &padding)) {

	RSA_free(rsa);
	return enif_make_badarg(env);
    }

    enif_alloc_binary(RSA_size(rsa), &ret_bin); 

    if (argv[3] == atom_true) {
	ERL_VALGRIND_ASSERT_MEM_DEFINED(data_bin.data,data_bin.size);
	i = RSA_public_encrypt(data_bin.size, data_bin.data,
			       ret_bin.data, rsa, padding);
	if (i > 0) {
	    ERL_VALGRIND_MAKE_MEM_DEFINED(ret_bin.data, i);
	}
    }
    else {
	i = RSA_public_decrypt(data_bin.size, data_bin.data,
			       ret_bin.data, rsa, padding);    
	if (i > 0) {
	    ERL_VALGRIND_MAKE_MEM_DEFINED(ret_bin.data, i);
	    enif_realloc_binary(&ret_bin, i);
	}
    }
    RSA_free(rsa);
    if (i > 0) {
	return enif_make_binary(env,&ret_bin);
    }
    else {
	enif_release_binary(&ret_bin);
	return atom_error;
    }
}

static ERL_NIF_TERM rsa_private_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Data, PublKey=[E,N,D], Padding, IsEncrypt) */
    ErlNifBinary data_bin, ret_bin;
    ERL_NIF_TERM head, tail;
    int padding, i;
    RSA* rsa = RSA_new();

    if (!enif_inspect_binary(env, argv[0], &data_bin)
	|| !enif_get_list_cell(env, argv[1], &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->e)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->n)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &rsa->d)
	|| !enif_is_empty_list(env,tail)
	|| !rsa_pad(argv[2], &padding)) {

	RSA_free(rsa);
	return enif_make_badarg(env);
    }

    enif_alloc_binary(RSA_size(rsa), &ret_bin); 

    if (argv[3] == atom_true) {
	ERL_VALGRIND_ASSERT_MEM_DEFINED(data_bin.data,data_bin.size);
	i = RSA_private_encrypt(data_bin.size, data_bin.data,
				ret_bin.data, rsa, padding);
	if (i > 0) {
	    ERL_VALGRIND_MAKE_MEM_DEFINED(ret_bin.data, i);
	}
    }
    else {
	i = RSA_private_decrypt(data_bin.size, data_bin.data,
				ret_bin.data, rsa, padding);       
	if (i > 0) {
	    ERL_VALGRIND_MAKE_MEM_DEFINED(ret_bin.data, i);
	    enif_realloc_binary(&ret_bin, i);
	}
    }
    RSA_free(rsa);
    if (i > 0) {
	return enif_make_binary(env,&ret_bin);
    }
    else {
	enif_release_binary(&ret_bin);
	return atom_error;
    }
}

static ERL_NIF_TERM dh_generate_parameters_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (PrimeLen, Generator) */
    int prime_len, generator;
    DH* dh_params;
    int p_len, g_len;
    unsigned char *p_ptr, *g_ptr;
    ERL_NIF_TERM ret_p, ret_g;

    if (!enif_get_int(env, argv[0], &prime_len)
	|| !enif_get_int(env, argv[1], &generator)) {

	return enif_make_badarg(env);
    }
    dh_params = DH_generate_parameters(prime_len, generator, NULL, NULL);
    if (dh_params == NULL) {
	return atom_error;
    }
    p_len = BN_num_bytes(dh_params->p);
    g_len = BN_num_bytes(dh_params->g);
    p_ptr = enif_make_new_binary(env, p_len+4, &ret_p);
    g_ptr = enif_make_new_binary(env, g_len+4, &ret_g);
    put_int32(p_ptr, p_len);
    put_int32(g_ptr, g_len);
    BN_bn2bin(dh_params->p, p_ptr+4);
    BN_bn2bin(dh_params->g, g_ptr+4);
    ERL_VALGRIND_MAKE_MEM_DEFINED(p_ptr+4, p_len);                
    ERL_VALGRIND_MAKE_MEM_DEFINED(g_ptr+4, g_len);
    DH_free(dh_params);
    return enif_make_list2(env, ret_p, ret_g);    
}

static ERL_NIF_TERM dh_check(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* ([PrimeLen, Generator]) */
    DH* dh_params = DH_new();
    int i;
    ERL_NIF_TERM ret, head, tail;

    if (!enif_get_list_cell(env, argv[0], &head, &tail)   
	|| !get_bn_from_mpint(env, head, &dh_params->p)
	|| !enif_get_list_cell(env, tail, &head, &tail)   
	|| !get_bn_from_mpint(env, head, &dh_params->g)
	|| !enif_is_empty_list(env,tail)) {

	DH_free(dh_params);
	return enif_make_badarg(env);
    }
    if (DH_check(dh_params, &i)) {
	if (i == 0) ret = atom_ok;
	else if (i & DH_CHECK_P_NOT_PRIME) ret = atom_not_prime;
	else if (i & DH_CHECK_P_NOT_SAFE_PRIME)	ret = atom_not_strong_prime;
	else if (i & DH_UNABLE_TO_CHECK_GENERATOR) ret = atom_unable_to_check_generator;
	else if (i & DH_NOT_SUITABLE_GENERATOR)	ret = atom_not_suitable_generator;
	else ret = enif_make_tuple2(env, atom_unknown, enif_make_uint(env, i));
    }
    else { /* Check Failed */       
	ret = enif_make_tuple2(env, atom_error, atom_check_failed);
    }
    DH_free(dh_params);
    return ret;
}   

static ERL_NIF_TERM dh_generate_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (PrivKey, DHParams=[P,G]) */
    DH* dh_params = DH_new();
    int pub_len, prv_len;
    unsigned char *pub_ptr, *prv_ptr;
    ERL_NIF_TERM ret, ret_pub, ret_prv, head, tail;

    if (!(get_bn_from_mpint(env, argv[0], &dh_params->priv_key)
	  || argv[0] == atom_undefined)
	|| !enif_get_list_cell(env, argv[1], &head, &tail)
	|| !get_bn_from_mpint(env, head, &dh_params->p)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dh_params->g)
	|| !enif_is_empty_list(env, tail)) {
	DH_free(dh_params);
	return enif_make_badarg(env);
    }

    if (DH_generate_key(dh_params)) {
	pub_len = BN_num_bytes(dh_params->pub_key);
	prv_len = BN_num_bytes(dh_params->priv_key);    
	pub_ptr = enif_make_new_binary(env, pub_len+4, &ret_pub);
	prv_ptr = enif_make_new_binary(env, prv_len+4, &ret_prv);
	put_int32(pub_ptr, pub_len);
	put_int32(prv_ptr, prv_len);
	BN_bn2bin(dh_params->pub_key, pub_ptr+4);
	BN_bn2bin(dh_params->priv_key, prv_ptr+4);
	ERL_VALGRIND_MAKE_MEM_DEFINED(pub_ptr+4, pub_len);    
	ERL_VALGRIND_MAKE_MEM_DEFINED(prv_ptr+4, prv_len);
	ret = enif_make_tuple2(env, ret_pub, ret_prv);
    }
    else {
	ret = atom_error;
    }
    DH_free(dh_params);
    return ret;
}

static ERL_NIF_TERM dh_compute_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (OthersPublicKey, MyPrivateKey, DHParams=[P,G]) */
    DH* dh_params = DH_new();
    BIGNUM* pubkey = NULL;
    int i;
    ErlNifBinary ret_bin;
    ERL_NIF_TERM ret, head, tail;

    if (!get_bn_from_mpint(env, argv[0], &pubkey)
	|| !get_bn_from_mpint(env, argv[1], &dh_params->priv_key)       
	|| !enif_get_list_cell(env, argv[2], &head, &tail)
	|| !get_bn_from_mpint(env, head, &dh_params->p)
	|| !enif_get_list_cell(env, tail, &head, &tail)
	|| !get_bn_from_mpint(env, head, &dh_params->g)
	|| !enif_is_empty_list(env, tail)) {

	ret = enif_make_badarg(env);
    }
    else {
	enif_alloc_binary(DH_size(dh_params), &ret_bin);
	i = DH_compute_key(ret_bin.data, pubkey, dh_params);
	if (i > 0) {
	    if (i != ret_bin.size) {
		enif_realloc_binary(&ret_bin, i); 
	    }
	    ret = enif_make_binary(env, &ret_bin);
	}
	else {
	    ret = atom_error;
	}
    }
    if (pubkey) BN_free(pubkey);
    DH_free(dh_params);
    return ret;
}

static ERL_NIF_TERM bf_cfb64_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])    
{/* (Key, Ivec, Data, IsEncrypt) */
    ErlNifBinary key_bin, ivec_bin, data_bin;
    BF_KEY bf_key; /* blowfish key 8 */
    unsigned char bf_tkey[8]; /* blowfish ivec */    
    int bf_n = 0; /* blowfish ivec pos */
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
	|| !enif_inspect_binary(env, argv[1], &ivec_bin)
	|| ivec_bin.size != 8 
	|| !enif_inspect_iolist_as_binary(env, argv[2], &data_bin)) {
	return enif_make_badarg(env);
    }

    BF_set_key(&bf_key, key_bin.size, key_bin.data);
    memcpy(bf_tkey, ivec_bin.data, 8);
    BF_cfb64_encrypt(data_bin.data, enif_make_new_binary(env,data_bin.size,&ret),
		     data_bin.size, &bf_key, bf_tkey, &bf_n,
		     (argv[3] == atom_true ? BF_ENCRYPT : BF_DECRYPT));
    return ret;
}

static ERL_NIF_TERM bf_cbc_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (Key, Ivec, Data, IsEncrypt) */
    ErlNifBinary key_bin, ivec_bin, data_bin;
    BF_KEY bf_key; /* blowfish key 8 */
    unsigned char bf_tkey[8]; /* blowfish ivec */    
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
	|| !enif_inspect_binary(env, argv[1], &ivec_bin)
	|| ivec_bin.size != 8 
	|| !enif_inspect_iolist_as_binary(env, argv[2], &data_bin)
	|| data_bin.size % 8 != 0) {
	return enif_make_badarg(env);
    }

    BF_set_key(&bf_key, key_bin.size, key_bin.data);
    memcpy(bf_tkey, ivec_bin.data, 8);
    BF_cbc_encrypt(data_bin.data, enif_make_new_binary(env,data_bin.size,&ret),
		   data_bin.size, &bf_key, bf_tkey,
		   (argv[3] == atom_true ? BF_ENCRYPT : BF_DECRYPT));
    return ret;
}

static ERL_NIF_TERM bf_ecb_crypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])    
{/* (Key, Data, IsEncrypt) */
    ErlNifBinary key_bin, data_bin;
    BF_KEY bf_key; /* blowfish key 8 */
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
	|| !enif_inspect_iolist_as_binary(env, argv[1], &data_bin)
	|| data_bin.size < 8) {
	return enif_make_badarg(env);
    }
    BF_set_key(&bf_key, key_bin.size, key_bin.data);
    BF_ecb_encrypt(data_bin.data, enif_make_new_binary(env,data_bin.size,&ret),
		   &bf_key, (argv[2] == atom_true ? BF_ENCRYPT : BF_DECRYPT));
    return ret;
}

static ERL_NIF_TERM blowfish_ofb64_encrypt(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])    
{/* (Key, IVec, Data) */
    ErlNifBinary key_bin, ivec_bin, data_bin;
    BF_KEY bf_key; /* blowfish key 8 */
    unsigned char bf_tkey[8]; /* blowfish ivec */    
    int bf_n = 0; /* blowfish ivec pos */
    ERL_NIF_TERM ret;

    if (!enif_inspect_iolist_as_binary(env, argv[0], &key_bin)
	|| !enif_inspect_binary(env, argv[1], &ivec_bin)
	|| ivec_bin.size != 8 
	|| !enif_inspect_iolist_as_binary(env, argv[2], &data_bin)) {
	return enif_make_badarg(env);
    }

    BF_set_key(&bf_key, key_bin.size, key_bin.data);
    memcpy(bf_tkey, ivec_bin.data, 8);
    BF_ofb64_encrypt(data_bin.data, enif_make_new_binary(env,data_bin.size,&ret),
		     data_bin.size, &bf_key, bf_tkey, &bf_n);
    return ret;
}



#ifdef OPENSSL_THREADS /* vvvvvvvvvvvvvvv OPENSSL_THREADS vvvvvvvvvvvvvvvv */

static INLINE void locking(int mode, ErlNifRWLock* lock)
{
    switch (mode) {
    case CRYPTO_LOCK|CRYPTO_READ:
	enif_rwlock_rlock(lock);
	break;
    case CRYPTO_LOCK|CRYPTO_WRITE:
	enif_rwlock_rwlock(lock);
	break;
    case CRYPTO_UNLOCK|CRYPTO_READ:
	enif_rwlock_runlock(lock);
	break;
    case CRYPTO_UNLOCK|CRYPTO_WRITE:
	enif_rwlock_rwunlock(lock);
	break;
    default:
	ASSERT(!"Invalid lock mode");
    }
}

/* Callback from openssl for static locking
 */
static void locking_function(int mode, int n, const char *file, int line)
{
    ASSERT(n>=0 && n<CRYPTO_num_locks());

    locking(mode, lock_vec[n]);
}

/* Callback from openssl for thread id
 */
static unsigned long id_function(void)
{
    return(unsigned long) enif_thread_self();
}

/* Callbacks for dynamic locking, not used by current openssl version (0.9.8)
 */
static struct CRYPTO_dynlock_value* dyn_create_function(const char *file, int line) {
    return(struct CRYPTO_dynlock_value*) enif_rwlock_create("crypto_dyn");
}
static void dyn_lock_function(int mode, struct CRYPTO_dynlock_value* ptr,const char *file, int line)
{
    locking(mode, (ErlNifRWLock*)ptr);
}
static void dyn_destroy_function(struct CRYPTO_dynlock_value *ptr, const char *file, int line)
{
    enif_rwlock_destroy((ErlNifRWLock*)ptr);
}

#endif /* ^^^^^^^^^^^^^^^^^^^^^^ OPENSSL_THREADS ^^^^^^^^^^^^^^^^^^^^^^ */

/* HMAC */

static void hmac_md5(unsigned char *key, int klen, unsigned char *dbuf, int dlen,
		     unsigned char *hmacbuf)
{
    MD5_CTX ctx;
    char ipad[HMAC_INT_LEN];
    char opad[HMAC_INT_LEN];
    unsigned char nkey[MD5_LEN];
    int i;

    /* Change key if longer than 64 bytes */
    if (klen > HMAC_INT_LEN) {
	MD5(key, klen, nkey);
	key = nkey;
	klen = MD5_LEN;
    }

    memset(ipad, '\0', sizeof(ipad));
    memset(opad, '\0', sizeof(opad));
    memcpy(ipad, key, klen);
    memcpy(opad, key, klen);

    for (i = 0; i < HMAC_INT_LEN; i++) {
	ipad[i] ^= HMAC_IPAD;
	opad[i] ^= HMAC_OPAD;
    }

    /* inner MD5 */
    MD5_Init(&ctx);
    MD5_Update(&ctx, ipad, HMAC_INT_LEN);
    MD5_Update(&ctx, dbuf, dlen);
    MD5_Final((unsigned char *) hmacbuf, &ctx);
    /* outer MD5 */
    MD5_Init(&ctx);
    MD5_Update(&ctx, opad, HMAC_INT_LEN);
    MD5_Update(&ctx, hmacbuf, MD5_LEN);
    MD5_Final((unsigned char *) hmacbuf, &ctx);
}

static void hmac_sha1(unsigned char *key, int klen,
		      unsigned char *dbuf, int dlen, 
		      unsigned char *hmacbuf)
{
    SHA_CTX ctx;
    char ipad[HMAC_INT_LEN];
    char opad[HMAC_INT_LEN];
    unsigned char nkey[SHA_LEN];
    int i;

    /* Change key if longer than 64 bytes */
    if (klen > HMAC_INT_LEN) {
	SHA1(key, klen, nkey);
	key = nkey;
	klen = SHA_LEN;
    }

    memset(ipad, '\0', sizeof(ipad));
    memset(opad, '\0', sizeof(opad));
    memcpy(ipad, key, klen);
    memcpy(opad, key, klen);

    for (i = 0; i < HMAC_INT_LEN; i++) {
	ipad[i] ^= HMAC_IPAD;
	opad[i] ^= HMAC_OPAD;
    }

    /* inner SHA */
    SHA1_Init(&ctx);
    SHA1_Update(&ctx, ipad, HMAC_INT_LEN);
    SHA1_Update(&ctx, dbuf, dlen);
    SHA1_Final((unsigned char *) hmacbuf, &ctx);
    /* outer SHA */
    SHA1_Init(&ctx);
    SHA1_Update(&ctx, opad, HMAC_INT_LEN);
    SHA1_Update(&ctx, hmacbuf, SHA_LEN);
    SHA1_Final((unsigned char *) hmacbuf, &ctx);
}