diff --git a/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c b/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c index 64d15819..51667d02 100644 --- a/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c +++ b/src/libsodium/crypto_core/curve25519/ref10/curve25519_ref10.c @@ -1913,6 +1913,61 @@ ge_scalarmult_base(ge_p3 *h, const unsigned char *a) } } +/* multiply by the order of the main subgroup l = 2^252+27742317777372353535851937790883648493 */ +void +ge_mul_l(ge_p3 *r, const ge_p3 *A) +{ + static const signed char aslide[253] = { + 13, 0, 0, 0, 0, -1, 0, 0, 0, 0, -11, 0, 0, 0, 0, 0, 0, -5, 0, 0, 0, 0, 0, 0, -3, 0, 0, 0, 0, -13, 0, 0, 0, 0, 7, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, -13, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, -13, 0, 0, 0, 0, 0, 0, -3, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 3, 0, 0, 0, 0, -11, 0, 0, 0, 0, 0, 0, 0, 15, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, -1, 0, 0, 0, 0, 7, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1 + }; + ge_cached Ai[8]; + ge_p1p1 t; + ge_p3 u; + ge_p3 A2; + int i; + + ge_p3_to_cached(&Ai[0], A); + ge_p3_dbl(&t, A); + ge_p1p1_to_p3(&A2, &t); + ge_add(&t, &A2, &Ai[0]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[1], &u); + ge_add(&t, &A2, &Ai[1]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[2], &u); + ge_add(&t, &A2, &Ai[2]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[3], &u); + ge_add(&t, &A2, &Ai[3]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[4], &u); + ge_add(&t, &A2, &Ai[4]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[5], &u); + ge_add(&t, &A2, &Ai[5]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[6], &u); + ge_add(&t, &A2, &Ai[6]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[7], &u); + + ge_p3_0(r); + + for (i = 252; i >= 0; --i) { + ge_p3_dbl(&t, r); + + if (aslide[i] > 0) { + ge_p1p1_to_p3(&u, &t); + ge_add(&t, &u, &Ai[aslide[i] / 2]); + } else if (aslide[i] < 0) { + ge_p1p1_to_p3(&u, &t); + ge_sub(&t, &u, &Ai[(-aslide[i]) / 2]); + } + + ge_p1p1_to_p3(r, &t); + } +} + /* Input: a[0]+256*a[1]+...+256^31*a[31] = a diff --git a/src/libsodium/crypto_sign/ed25519/ref10/keypair.c b/src/libsodium/crypto_sign/ed25519/ref10/keypair.c index 131a36a5..bdc6b017 100644 --- a/src/libsodium/crypto_sign/ed25519/ref10/keypair.c +++ b/src/libsodium/crypto_sign/ed25519/ref10/keypair.c @@ -42,13 +42,6 @@ crypto_sign_ed25519_keypair(unsigned char *pk, unsigned char *sk) return ret; } -/* 2^252+27742317777372353535851937790883648493 */ -static const unsigned char L[32] = { - 0xed, 0xd3, 0xf5, 0x5c, 0x1a, 0x63, 0x12, 0x58, 0xd6, 0x9c, 0xf7, - 0xa2, 0xde, 0xf9, 0xde, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, - 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10 -}; - int crypto_sign_ed25519_pk_to_curve25519(unsigned char *curve25519_pk, const unsigned char *ed25519_pk) @@ -62,7 +55,7 @@ crypto_sign_ed25519_pk_to_curve25519(unsigned char *curve25519_pk, ge_frombytes_negate_vartime(&A, ed25519_pk) != 0) { return -1; } - ge_scalarmult_vartime(&pl, L, &A); + ge_mul_l(&pl, &A); if (fe_isnonzero(pl.X)) { return -1; } diff --git a/src/libsodium/include/sodium/private/curve25519_ref10.h b/src/libsodium/include/sodium/private/curve25519_ref10.h index 2b9caeb1..4d6315e8 100644 --- a/src/libsodium/include/sodium/private/curve25519_ref10.h +++ b/src/libsodium/include/sodium/private/curve25519_ref10.h @@ -123,6 +123,7 @@ typedef struct { #define ge_scalarmult_base crypto_core_curve25519_ref10_ge_scalarmult_base #define ge_double_scalarmult_vartime crypto_core_curve25519_ref10_ge_double_scalarmult_vartime #define ge_scalarmult_vartime crypto_core_curve25519_ref10_ge_scalarmult_vartime +#define ge_mul_l crypto_core_curve25519_ref10_ge_mul_l extern void ge_tobytes(unsigned char *,const ge_p2 *); extern void ge_p3_tobytes(unsigned char *,const ge_p3 *); @@ -145,6 +146,7 @@ extern void ge_sub(ge_p1p1 *,const ge_p3 *,const ge_cached *); extern void ge_scalarmult_base(ge_p3 *,const unsigned char *); extern void ge_double_scalarmult_vartime(ge_p2 *,const unsigned char *,const ge_p3 *,const unsigned char *); extern void ge_scalarmult_vartime(ge_p3 *,const unsigned char *,const ge_p3 *); +extern void ge_mul_l(ge_p3 *r, const ge_p3 *A); /* The set of scalars is \Z/l