diff options
Diffstat (limited to 'src/crypto/crypto-ops.c')
| -rw-r--r-- | src/crypto/crypto-ops.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/src/crypto/crypto-ops.c b/src/crypto/crypto-ops.c index b5c62bce4..f8e767875 100644 --- a/src/crypto/crypto-ops.c +++ b/src/crypto/crypto-ops.c @@ -1234,6 +1234,51 @@ void ge_double_scalarmult_base_vartime(ge_p2 *r, const unsigned char *a, const g } } +void ge_double_scalarmult_base_vartime_p3(ge_p3 *r3, const unsigned char *a, const ge_p3 *A, const unsigned char *b) { + signed char aslide[256]; + signed char bslide[256]; + ge_dsmp Ai; /* A, 3A, 5A, 7A, 9A, 11A, 13A, 15A */ + ge_p1p1 t; + ge_p3 u; + ge_p2 r; + int i; + + slide(aslide, a); + slide(bslide, b); + ge_dsm_precomp(Ai, A); + + ge_p2_0(&r); + + for (i = 255; i >= 0; --i) { + if (aslide[i] || bslide[i]) break; + } + + for (; i >= 0; --i) { + ge_p2_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]); + } + + if (bslide[i] > 0) { + ge_p1p1_to_p3(&u, &t); + ge_madd(&t, &u, &ge_Bi[bslide[i]/2]); + } else if (bslide[i] < 0) { + ge_p1p1_to_p3(&u, &t); + ge_msub(&t, &u, &ge_Bi[(-bslide[i])/2]); + } + + if (i == 0) + ge_p1p1_to_p3(r3, &t); + else + ge_p1p1_to_p2(&r, &t); + } +} + /* From ge_frombytes.c, modified */ int ge_frombytes_vartime(ge_p3 *h, const unsigned char *s) { @@ -2000,6 +2045,70 @@ void ge_scalarmult(ge_p2 *r, const unsigned char *a, const ge_p3 *A) { } } +void ge_scalarmult_p3(ge_p3 *r3, const unsigned char *a, const ge_p3 *A) { + signed char e[64]; + int carry, carry2, i; + ge_cached Ai[8]; /* 1 * A, 2 * A, ..., 8 * A */ + ge_p1p1 t; + ge_p3 u; + ge_p2 r; + + carry = 0; /* 0..1 */ + for (i = 0; i < 31; i++) { + carry += a[i]; /* 0..256 */ + carry2 = (carry + 8) >> 4; /* 0..16 */ + e[2 * i] = carry - (carry2 << 4); /* -8..7 */ + carry = (carry2 + 8) >> 4; /* 0..1 */ + e[2 * i + 1] = carry2 - (carry << 4); /* -8..7 */ + } + carry += a[31]; /* 0..128 */ + carry2 = (carry + 8) >> 4; /* 0..8 */ + e[62] = carry - (carry2 << 4); /* -8..7 */ + e[63] = carry2; /* 0..8 */ + + ge_p3_to_cached(&Ai[0], A); + for (i = 0; i < 7; i++) { + ge_add(&t, A, &Ai[i]); + ge_p1p1_to_p3(&u, &t); + ge_p3_to_cached(&Ai[i + 1], &u); + } + + ge_p2_0(&r); + for (i = 63; i >= 0; i--) { + signed char b = e[i]; + unsigned char bnegative = negative(b); + unsigned char babs = b - (((-bnegative) & b) << 1); + ge_cached cur, minuscur; + ge_p2_dbl(&t, &r); + ge_p1p1_to_p2(&r, &t); + ge_p2_dbl(&t, &r); + ge_p1p1_to_p2(&r, &t); + ge_p2_dbl(&t, &r); + ge_p1p1_to_p2(&r, &t); + ge_p2_dbl(&t, &r); + ge_p1p1_to_p3(&u, &t); + ge_cached_0(&cur); + ge_cached_cmov(&cur, &Ai[0], equal(babs, 1)); + ge_cached_cmov(&cur, &Ai[1], equal(babs, 2)); + ge_cached_cmov(&cur, &Ai[2], equal(babs, 3)); + ge_cached_cmov(&cur, &Ai[3], equal(babs, 4)); + ge_cached_cmov(&cur, &Ai[4], equal(babs, 5)); + ge_cached_cmov(&cur, &Ai[5], equal(babs, 6)); + ge_cached_cmov(&cur, &Ai[6], equal(babs, 7)); + ge_cached_cmov(&cur, &Ai[7], equal(babs, 8)); + fe_copy(minuscur.YplusX, cur.YminusX); + fe_copy(minuscur.YminusX, cur.YplusX); + fe_copy(minuscur.Z, cur.Z); + fe_neg(minuscur.T2d, cur.T2d); + ge_cached_cmov(&cur, &minuscur, bnegative); + ge_add(&t, &u, &cur); + if (i == 0) + ge_p1p1_to_p3(r3, &t); + else + ge_p1p1_to_p2(&r, &t); + } +} + void ge_double_scalarmult_precomp_vartime2(ge_p2 *r, const unsigned char *a, const ge_dsmp Ai, const unsigned char *b, const ge_dsmp Bi) { signed char aslide[256]; signed char bslide[256]; @@ -2039,6 +2148,49 @@ void ge_double_scalarmult_precomp_vartime2(ge_p2 *r, const unsigned char *a, con } } +void ge_double_scalarmult_precomp_vartime2_p3(ge_p3 *r3, const unsigned char *a, const ge_dsmp Ai, const unsigned char *b, const ge_dsmp Bi) { + signed char aslide[256]; + signed char bslide[256]; + ge_p1p1 t; + ge_p3 u; + ge_p2 r; + int i; + + slide(aslide, a); + slide(bslide, b); + + ge_p2_0(&r); + + for (i = 255; i >= 0; --i) { + if (aslide[i] || bslide[i]) break; + } + + for (; i >= 0; --i) { + ge_p2_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]); + } + + if (bslide[i] > 0) { + ge_p1p1_to_p3(&u, &t); + ge_add(&t, &u, &Bi[bslide[i]/2]); + } else if (bslide[i] < 0) { + ge_p1p1_to_p3(&u, &t); + ge_sub(&t, &u, &Bi[(-bslide[i])/2]); + } + + if (i == 0) + ge_p1p1_to_p3(r3, &t); + else + ge_p1p1_to_p2(&r, &t); + } +} + void ge_double_scalarmult_precomp_vartime(ge_p2 *r, const unsigned char *a, const ge_p3 *A, const unsigned char *b, const ge_dsmp Bi) { ge_dsmp Ai; /* A, 3A, 5A, 7A, 9A, 11A, 13A, 15A */ |