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Diffstat (limited to 'comm/third_party/botan/src/lib/utils/poly_dbl/poly_dbl.cpp')
-rw-r--r-- | comm/third_party/botan/src/lib/utils/poly_dbl/poly_dbl.cpp | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/utils/poly_dbl/poly_dbl.cpp b/comm/third_party/botan/src/lib/utils/poly_dbl/poly_dbl.cpp new file mode 100644 index 0000000000..8c728a1480 --- /dev/null +++ b/comm/third_party/botan/src/lib/utils/poly_dbl/poly_dbl.cpp @@ -0,0 +1,115 @@ +/* +* (C) 2017,2018 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/internal/poly_dbl.h> +#include <botan/loadstor.h> +#include <botan/exceptn.h> + +namespace Botan { + +namespace { + +/* +* 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); + + BOTAN_IF_CONSTEXPR(LIMBS > 0) + { + 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; + + copy_out_be(out, LIMBS*8, W); + } + +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); + + BOTAN_IF_CONSTEXPR(LIMBS > 0) + { + 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; + + copy_out_le(out, LIMBS*8, W); + } + +} + +void poly_double_n(uint8_t out[], const uint8_t in[], size_t n) + { + switch(n) + { + case 8: + return poly_double<1, MinWeightPolynomial::P64>(out, in); + case 16: + return poly_double<2, MinWeightPolynomial::P128>(out, in); + case 24: + return poly_double<3, MinWeightPolynomial::P192>(out, in); + case 32: + return poly_double<4, MinWeightPolynomial::P256>(out, in); + case 64: + return poly_double<8, MinWeightPolynomial::P512>(out, in); + case 128: + return poly_double<16, MinWeightPolynomial::P1024>(out, in); + default: + throw Invalid_Argument("Unsupported size for poly_double_n"); + } + } + +void poly_double_n_le(uint8_t out[], const uint8_t in[], size_t n) + { + switch(n) + { + case 8: + return poly_double_le<1, MinWeightPolynomial::P64>(out, in); + case 16: + return poly_double_le<2, MinWeightPolynomial::P128>(out, in); + case 24: + return poly_double_le<3, MinWeightPolynomial::P192>(out, in); + case 32: + return poly_double_le<4, MinWeightPolynomial::P256>(out, in); + case 64: + return poly_double_le<8, MinWeightPolynomial::P512>(out, in); + case 128: + return poly_double_le<16, MinWeightPolynomial::P1024>(out, in); + default: + throw Invalid_Argument("Unsupported size for poly_double_n_le"); + } + } + +} |