diff options
Diffstat (limited to 'src/lib/utils/poly_dbl/poly_dbl.cpp')
| -rw-r--r-- | src/lib/utils/poly_dbl/poly_dbl.cpp | 48 |
1 files changed, 35 insertions, 13 deletions
diff --git a/src/lib/utils/poly_dbl/poly_dbl.cpp b/src/lib/utils/poly_dbl/poly_dbl.cpp index 2b989db57..62c7695da 100644 --- a/src/lib/utils/poly_dbl/poly_dbl.cpp +++ b/src/lib/utils/poly_dbl/poly_dbl.cpp @@ -1,5 +1,5 @@ /* -* (C) 2017 Jack Lloyd +* (C) 2017,2018 Jack Lloyd * * Botan is released under the Simplified BSD License (see license.txt) */ @@ -12,12 +12,28 @@ namespace Botan { namespace { -template<size_t LIMBS, uint64_t POLY> +/* +* The minimum weight irreducible binary polynomial of size n +* +* See http://www.hpl.hp.com/techreports/98/HPL-98-135.pdf +*/ +enum class MinWeightPolynomial : uint64_t { + P64 = 0x1B, + P128 = 0x87, + P192 = 0x87, + P256 = 0x425, + P512 = 0x125, + P1024 = 0x80043, +}; + +template<size_t LIMBS, MinWeightPolynomial P> void poly_double(uint8_t out[], const uint8_t in[]) { uint64_t W[LIMBS]; load_be(W, in, LIMBS); + const uint64_t POLY = static_cast<uint64_t>(P); + 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); @@ -26,12 +42,14 @@ void poly_double(uint8_t out[], const uint8_t in[]) copy_out_be(out, LIMBS*8, W); } -template<size_t LIMBS, uint64_t POLY> +template<size_t LIMBS, MinWeightPolynomial P> void poly_double_le(uint8_t out[], const uint8_t in[]) { uint64_t W[LIMBS]; load_le(W, in, LIMBS); + const uint64_t POLY = static_cast<uint64_t>(P); + 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); @@ -47,15 +65,17 @@ 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); + return poly_double<1, MinWeightPolynomial::P64>(out, in); case 16: - return poly_double<2, 0x87>(out, in); + return poly_double<2, MinWeightPolynomial::P128>(out, in); case 24: - return poly_double<3, 0x87>(out, in); + return poly_double<3, MinWeightPolynomial::P192>(out, in); case 32: - return poly_double<4, 0x425>(out, in); + return poly_double<4, MinWeightPolynomial::P256>(out, in); case 64: - return poly_double<8, 0x125>(out, in); + return poly_double<8, MinWeightPolynomial::P512>(out, in); + case 128: + return poly_double<8, MinWeightPolynomial::P1024>(out, in); default: throw Invalid_Argument("Unsupported size for poly_double_n"); } @@ -66,15 +86,17 @@ void poly_double_n_le(uint8_t out[], const uint8_t in[], size_t n) switch(n) { case 8: - return poly_double_le<1, 0x1B>(out, in); + return poly_double_le<1, MinWeightPolynomial::P64>(out, in); case 16: - return poly_double_le<2, 0x87>(out, in); + return poly_double_le<2, MinWeightPolynomial::P128>(out, in); case 24: - return poly_double_le<3, 0x87>(out, in); + return poly_double_le<3, MinWeightPolynomial::P192>(out, in); case 32: - return poly_double_le<4, 0x425>(out, in); + return poly_double_le<4, MinWeightPolynomial::P256>(out, in); case 64: - return poly_double_le<8, 0x125>(out, in); + return poly_double_le<8, MinWeightPolynomial::P512>(out, in); + case 128: + return poly_double_le<8, MinWeightPolynomial::P1024>(out, in); default: throw Invalid_Argument("Unsupported size for poly_double_n_le"); } |