openssl/crypto/bn_int.h

/*
 * Some BIGNUM functions assume most significant limb to be non-zero, which
 * is customarily arranged by bn_correct_top. Output from below functions
 * is not processed with bn_correct_top, and for this reason it may not be
 * returned out of public API. It may only be passed internally into other
 * functions known to support non-minimal or zero-padded BIGNUMs.
 */
int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
                          BN_MONT_CTX *mont, BN_CTX *ctx);
int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
                         BN_CTX *ctx);
bn/bn_{mont\|exp}.c: switch to zero-padded intermediate vectors. Note that exported functions maintain original behaviour, so that external callers won't observe difference. While internally we can now perform Montogomery multiplication on fixed-length vectors, fixed at modulus size. The new functions, bn_to_mont_fixed_top and bn_mul_mont_fixed_top, are declared in bn_int.h, because one can use them even outside bn, e.g. in RSA, DSA, ECDSA... Reviewed-by: Rich Salz <rsalz@openssl.org> (Merged from https://github.com/openssl/openssl/pull/6810) (cherry picked from commit 71883868ea5b33416ae8283bcc38dd2d97e5006b) Resolved conflicts: crypto/bn/bn_exp.c crypto/bn/bn_lcl.h crypto/bn/bn_mont.c crypto/include/internal/bn_int.h 2018-07-06 15:13:15 +02:00			`/*`
			`* Some BIGNUM functions assume most significant limb to be non-zero, which`
			`* is customarily arranged by bn_correct_top. Output from below functions`
			`* is not processed with bn_correct_top, and for this reason it may not be`
			`* returned out of public API. It may only be passed internally into other`
			`* functions known to support non-minimal or zero-padded BIGNUMs.`
			`*/`
			`int bn_mul_mont_fixed_top(BIGNUM r, const BIGNUM a, const BIGNUM *b,`
			`BN_MONT_CTX mont, BN_CTX ctx);`
			`int bn_to_mont_fixed_top(BIGNUM r, const BIGNUM a, BN_MONT_CTX *mont,`
			`BN_CTX *ctx);`