/* crypto/dh/dh_key.c */
-/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
#include <stdio.h>
#include "cryptlib.h"
-#include "bn.h"
-#include "rand.h"
-#include "dh.h"
+#include <openssl/bn.h>
+#include <openssl/rand.h>
+#include <openssl/dh.h>
-int DH_generate_key(dh)
-DH *dh;
+static int generate_key(DH *dh);
+static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh);
+static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
+ const BIGNUM *a, const BIGNUM *p,
+ const BIGNUM *m, BN_CTX *ctx,
+ BN_MONT_CTX *m_ctx);
+static int dh_init(DH *dh);
+static int dh_finish(DH *dh);
+
+int DH_generate_key(DH *dh)
+ {
+ return dh->meth->generate_key(dh);
+ }
+
+int DH_compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
+ {
+ return dh->meth->compute_key(key, pub_key, dh);
+ }
+
+static DH_METHOD dh_ossl = {
+"OpenSSL DH Method",
+generate_key,
+compute_key,
+dh_bn_mod_exp,
+dh_init,
+dh_finish,
+0,
+NULL,
+NULL
+};
+
+const DH_METHOD *DH_OpenSSL(void)
+{
+ return &dh_ossl;
+}
+
+static int generate_key(DH *dh)
{
int ok=0;
- unsigned int i;
- BN_CTX *ctx=NULL;
+ int generate_new_key=0;
+ unsigned l;
+ BN_CTX *ctx;
+ BN_MONT_CTX *mont=NULL;
BIGNUM *pub_key=NULL,*priv_key=NULL;
- ctx=BN_CTX_new();
+ ctx = BN_CTX_new();
if (ctx == NULL) goto err;
if (dh->priv_key == NULL)
{
- i=dh->length;
- if (i == 0)
- {
- /* Make the number p-1 bits long */
- i=BN_num_bits(dh->p)-1;
- }
priv_key=BN_new();
if (priv_key == NULL) goto err;
- if (!BN_rand(priv_key,i,0,0)) goto err;
+ generate_new_key=1;
}
else
priv_key=dh->priv_key;
else
pub_key=dh->pub_key;
- if (!BN_mod_exp(pub_key,dh->g,priv_key,dh->p,ctx)) goto err;
+
+ if (dh->flags & DH_FLAG_CACHE_MONT_P)
+ {
+ mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
+ CRYPTO_LOCK_DH, dh->p, ctx);
+ if (!mont)
+ goto err;
+ }
+
+ if (generate_new_key)
+ {
+ l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */
+ if (!BN_rand(priv_key, l, 0, 0)) goto err;
+ }
+
+ {
+ BIGNUM local_prk;
+ BIGNUM *prk;
+
+ if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
+ {
+ BN_init(&local_prk);
+ prk = &local_prk;
+ BN_with_flags(prk, priv_key, BN_FLG_EXP_CONSTTIME);
+ }
+ else
+ prk = priv_key;
+
+ if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) goto err;
+ }
dh->pub_key=pub_key;
dh->priv_key=priv_key;
ok=1;
err:
if (ok != 1)
- DHerr(DH_F_DH_GENERATE_KEY,ERR_R_BN_LIB);
+ DHerr(DH_F_GENERATE_KEY,ERR_R_BN_LIB);
if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key);
if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
- if (ctx != NULL) BN_CTX_free(ctx);
+ BN_CTX_free(ctx);
return(ok);
}
-int DH_compute_key(key,pub_key,dh)
-unsigned char *key;
-BIGNUM *pub_key;
-DH *dh;
+static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
{
BN_CTX *ctx;
+ BN_MONT_CTX *mont=NULL;
BIGNUM *tmp;
int ret= -1;
+ int check_result;
- ctx=BN_CTX_new();
+ ctx = BN_CTX_new();
if (ctx == NULL) goto err;
- tmp=ctx->bn[ctx->tos++];
+ BN_CTX_start(ctx);
+ tmp = BN_CTX_get(ctx);
if (dh->priv_key == NULL)
{
- DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
+ DHerr(DH_F_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
goto err;
}
- if (!BN_mod_exp(tmp,pub_key,dh->priv_key,dh->p,ctx))
+
+ if (dh->flags & DH_FLAG_CACHE_MONT_P)
{
- DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
+ mont = BN_MONT_CTX_set_locked(&dh->method_mont_p,
+ CRYPTO_LOCK_DH, dh->p, ctx);
+ if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
+ {
+ /* XXX */
+ BN_set_flags(dh->priv_key, BN_FLG_EXP_CONSTTIME);
+ }
+ if (!mont)
+ goto err;
+ }
+
+ if (!DH_check_pub_key(dh, pub_key, &check_result) || check_result)
+ {
+ DHerr(DH_F_COMPUTE_KEY,DH_R_INVALID_PUBKEY);
+ goto err;
+ }
+
+ if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
+ {
+ DHerr(DH_F_COMPUTE_KEY,ERR_R_BN_LIB);
goto err;
}
ret=BN_bn2bin(tmp,key);
err:
- if (ctx != NULL) BN_CTX_free(ctx);
+ if (ctx != NULL)
+ {
+ BN_CTX_end(ctx);
+ BN_CTX_free(ctx);
+ }
return(ret);
}
+
+static int dh_bn_mod_exp(const DH *dh, BIGNUM *r,
+ const BIGNUM *a, const BIGNUM *p,
+ const BIGNUM *m, BN_CTX *ctx,
+ BN_MONT_CTX *m_ctx)
+ {
+ /* If a is only one word long and constant time is false, use the faster
+ * exponenentiation function.
+ */
+ if (a->top == 1 && ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) != 0))
+ {
+ BN_ULONG A = a->d[0];
+ return BN_mod_exp_mont_word(r,A,p,m,ctx,m_ctx);
+ }
+ else
+ return BN_mod_exp_mont(r,a,p,m,ctx,m_ctx);
+ }
+
+
+static int dh_init(DH *dh)
+ {
+ dh->flags |= DH_FLAG_CACHE_MONT_P;
+ return(1);
+ }
+
+static int dh_finish(DH *dh)
+ {
+ if(dh->method_mont_p)
+ BN_MONT_CTX_free(dh->method_mont_p);
+ return(1);
+ }
projects / openssl.git / blobdiff