diff options
Diffstat (limited to 'src/lib/utils')
| -rw-r--r-- | src/lib/utils/poly_dbl.cpp | 152 | ||||
| -rw-r--r-- | src/lib/utils/poly_dbl.h | 18 |
2 files changed, 65 insertions, 105 deletions
diff --git a/src/lib/utils/poly_dbl.cpp b/src/lib/utils/poly_dbl.cpp index 0cea4957b..2b989db57 100644 --- a/src/lib/utils/poly_dbl.cpp +++ b/src/lib/utils/poly_dbl.cpp @@ -10,120 +10,74 @@ namespace Botan { -void poly_double_n(uint8_t b[], size_t n) - { - if(n == 8) - return poly_double_8(b); - else if(n == 16) - return poly_double_16(b); - else if(n == 24) - return poly_double_24(b); - else if(n == 32) - return poly_double_32(b); - else if(n == 64) - return poly_double_64(b); - else - throw Invalid_Argument("Unsupported size for poly_double_n"); - } - -void poly_double_8(uint8_t b[8]) - { - const uint64_t poly = 0x1B; - uint64_t b0 = load_be<uint64_t>(b, 0); - const uint64_t carry0 = (b0 >> 63); - b0 = (b0 << 1) ^ (carry0 * poly); - store_be(b0, b); - } +namespace { -void poly_double_16(uint8_t b[16]) +template<size_t LIMBS, uint64_t POLY> +void poly_double(uint8_t out[], const uint8_t in[]) { - const uint64_t poly = 0x87; + uint64_t W[LIMBS]; + load_be(W, in, LIMBS); - uint64_t b0 = load_be<uint64_t>(b, 0); - uint64_t b1 = load_be<uint64_t>(b, 1); + const uint64_t carry = POLY * (W[0] >> 63); + for(size_t i = 0; i != LIMBS - 1; ++i) + W[i] = (W[i] << 1) ^ (W[i+1] >> 63); + W[LIMBS-1] = (W[LIMBS-1] << 1) ^ carry; - const uint64_t carry0 = (b0 >> 63); - - b0 = (b0 << 1) ^ (b1 >> 63); - b1 = (b1 << 1) ^ (carry0 * poly); - - store_be(b0, b); - store_be(b1, b+8); + copy_out_be(out, LIMBS*8, W); } -void poly_double_24(uint8_t b[24]) +template<size_t LIMBS, uint64_t POLY> +void poly_double_le(uint8_t out[], const uint8_t in[]) { - const uint64_t poly = 0x87; - - uint64_t b0 = load_be<uint64_t>(b, 0); - uint64_t b1 = load_be<uint64_t>(b, 1); - uint64_t b2 = load_be<uint64_t>(b, 2); + uint64_t W[LIMBS]; + load_le(W, in, LIMBS); - const uint64_t carry0 = (b0 >> 63); + const uint64_t carry = POLY * (W[LIMBS-1] >> 63); + for(size_t i = 0; i != LIMBS - 1; ++i) + W[LIMBS-1-i] = (W[LIMBS-1-i] << 1) ^ (W[LIMBS-2-i] >> 63); + W[0] = (W[0] << 1) ^ carry; - b0 = (b0 << 1) ^ (b1 >> 63); - b1 = (b1 << 1) ^ (b2 >> 63); - b2 = (b2 << 1) ^ (carry0 * poly); - - store_be(b0, b); - store_be(b1, b+8); - store_be(b2, b+16); + copy_out_le(out, LIMBS*8, W); } -void poly_double_32(uint8_t b[32]) - { - const uint64_t poly = 0x425; - - uint64_t b0 = load_be<uint64_t>(b, 0); - uint64_t b1 = load_be<uint64_t>(b, 1); - uint64_t b2 = load_be<uint64_t>(b, 2); - uint64_t b3 = load_be<uint64_t>(b, 3); - - const uint64_t carry0 = (b0 >> 63); - - b0 = (b0 << 1) ^ (b1 >> 63); - b1 = (b1 << 1) ^ (b2 >> 63); - b2 = (b2 << 1) ^ (b3 >> 63); - b3 = (b3 << 1) ^ (carry0 * poly); +} - store_be(b0, b); - store_be(b1, b+8); - store_be(b2, b+16); - store_be(b3, b+24); +void poly_double_n(uint8_t out[], const uint8_t in[], size_t n) + { + switch(n) + { + case 8: + return poly_double<1, 0x1B>(out, in); + case 16: + return poly_double<2, 0x87>(out, in); + case 24: + return poly_double<3, 0x87>(out, in); + case 32: + return poly_double<4, 0x425>(out, in); + case 64: + return poly_double<8, 0x125>(out, in); + default: + throw Invalid_Argument("Unsupported size for poly_double_n"); + } } -void poly_double_64(uint8_t b[64]) +void poly_double_n_le(uint8_t out[], const uint8_t in[], size_t n) { - const uint64_t poly = 0x125; - - uint64_t b0 = load_be<uint64_t>(b, 0); - uint64_t b1 = load_be<uint64_t>(b, 1); - uint64_t b2 = load_be<uint64_t>(b, 2); - uint64_t b3 = load_be<uint64_t>(b, 3); - uint64_t b4 = load_be<uint64_t>(b, 4); - uint64_t b5 = load_be<uint64_t>(b, 5); - uint64_t b6 = load_be<uint64_t>(b, 6); - uint64_t b7 = load_be<uint64_t>(b, 7); - - const uint64_t carry0 = (b0 >> 63); - - b0 = (b0 << 1) ^ (b1 >> 63); - b1 = (b1 << 1) ^ (b2 >> 63); - b2 = (b2 << 1) ^ (b3 >> 63); - b3 = (b3 << 1) ^ (b4 >> 63); - b4 = (b4 << 1) ^ (b5 >> 63); - b5 = (b5 << 1) ^ (b6 >> 63); - b6 = (b6 << 1) ^ (b7 >> 63); - b7 = (b7 << 1) ^ (carry0 * poly); - - store_be(b0, b); - store_be(b1, b+8); - store_be(b2, b+16); - store_be(b3, b+24); - store_be(b4, b+32); - store_be(b5, b+40); - store_be(b6, b+48); - store_be(b7, b+56); + switch(n) + { + case 8: + return poly_double_le<1, 0x1B>(out, in); + case 16: + return poly_double_le<2, 0x87>(out, in); + case 24: + return poly_double_le<3, 0x87>(out, in); + case 32: + return poly_double_le<4, 0x425>(out, in); + case 64: + return poly_double_le<8, 0x125>(out, in); + default: + throw Invalid_Argument("Unsupported size for poly_double_n_le"); + } } } diff --git a/src/lib/utils/poly_dbl.h b/src/lib/utils/poly_dbl.h index df3b419c3..c79af3ada 100644 --- a/src/lib/utils/poly_dbl.h +++ b/src/lib/utils/poly_dbl.h @@ -11,14 +11,20 @@ namespace Botan { -void BOTAN_DLL poly_double_n(uint8_t b[], size_t n); +/** +* Polynomial doubling in GF(2^n) +*/ +void BOTAN_DLL poly_double_n(uint8_t out[], const uint8_t in[], size_t n); -void poly_double_8(uint8_t b[8]); -void poly_double_16(uint8_t b[16]); -void poly_double_24(uint8_t b[24]); -void poly_double_32(uint8_t b[32]); -void poly_double_64(uint8_t b[64]); +inline void poly_double_n(uint8_t buf[], size_t n) + { + return poly_double_n(buf, buf, n); + } +/* +* Little endian convention - used for XTS +*/ +void poly_double_n_le(uint8_t out[], const uint8_t in[], size_t n); } |