Deprecate |BN_mod_exp_mont_word| and simplify its implementation.
|BN_mod_exp_mont_word| is only useful when the base is a single word
in length and timing side channel protection of the exponent is not
needed. That's never the case in real life.
Keep the function in the API, but removes its single-word-base
optimized implementation with a call to |BN_mod_exp_mont|.
Change-Id: Ic25f6d4f187210b681c6ee6b87038b64a5744958
Reviewed-on: https://boringssl-review.googlesource.com/7731
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/include/openssl/bn.h b/include/openssl/bn.h
index c66f887..8e57965 100644
--- a/include/openssl/bn.h
+++ b/include/openssl/bn.h
@@ -802,9 +802,6 @@
BN_CTX *ctx,
const BN_MONT_CTX *mont);
-OPENSSL_EXPORT int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
- const BIGNUM *m, BN_CTX *ctx,
- const BN_MONT_CTX *mont);
OPENSSL_EXPORT int BN_mod_exp2_mont(BIGNUM *r, const BIGNUM *a1,
const BIGNUM *p1, const BIGNUM *a2,
const BIGNUM *p2, const BIGNUM *m,
@@ -829,6 +826,13 @@
* is updated. */
OPENSSL_EXPORT BIGNUM *BN_mpi2bn(const uint8_t *in, size_t len, BIGNUM *out);
+/* BN_mod_exp_mont_word is like |BN_mod_exp_mont| except that the base |a| is
+ * given as a |BN_ULONG| instead of a |BIGNUM *|. It returns one on success
+ * or zero otherwise. */
+OPENSSL_EXPORT int BN_mod_exp_mont_word(BIGNUM *r, BN_ULONG a, const BIGNUM *p,
+ const BIGNUM *m, BN_CTX *ctx,
+ const BN_MONT_CTX *mont);
+
/* Private functions */