diff options
Diffstat (limited to 'comm/third_party/botan/src/lib/codec/base58/base58.cpp')
| -rw-r--r-- | comm/third_party/botan/src/lib/codec/base58/base58.cpp | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/codec/base58/base58.cpp b/comm/third_party/botan/src/lib/codec/base58/base58.cpp new file mode 100644 index 0000000000..a6d509012d --- /dev/null +++ b/comm/third_party/botan/src/lib/codec/base58/base58.cpp @@ -0,0 +1,189 @@ +/* +* (C) 2018,2020 Jack Lloyd +* +* Botan is released under the Simplified BSD License (see license.txt) +*/ + +#include <botan/base58.h> +#include <botan/exceptn.h> +#include <botan/bigint.h> +#include <botan/divide.h> +#include <botan/loadstor.h> +#include <botan/internal/ct_utils.h> +#include <botan/hash.h> + +namespace Botan { + +namespace { + +uint32_t sha256_d_checksum(const uint8_t input[], size_t input_length) + { + std::unique_ptr<HashFunction> sha256 = HashFunction::create_or_throw("SHA-256"); + + std::vector<uint8_t> checksum(32); + + sha256->update(input, input_length); + sha256->final(checksum); + + sha256->update(checksum); + sha256->final(checksum); + + return load_be<uint32_t>(checksum.data(), 0); + } + +char lookup_base58_char(uint8_t x) + { + // "123456789 ABCDEFGH JKLMN PQRSTUVWXYZ abcdefghijk mnopqrstuvwxyz" + BOTAN_DEBUG_ASSERT(x < 58); + + const auto is_dec_19 = CT::Mask<uint8_t>::is_lte(x, 8); + const auto is_alpha_AH = CT::Mask<uint8_t>::is_within_range(x, 9, 16); + const auto is_alpha_JN = CT::Mask<uint8_t>::is_within_range(x, 17, 21); + const auto is_alpha_PZ = CT::Mask<uint8_t>::is_within_range(x, 22, 32); + const auto is_alpha_ak = CT::Mask<uint8_t>::is_within_range(x, 33, 43); + // otherwise in 'm'-'z' + + const char c_19 = '1' + x; + const char c_AH = 'A' + (x - 9); + const char c_JN = 'J' + (x - 17); + const char c_PZ = 'P' + (x - 22); + const char c_ak = 'a' + (x - 33); + const char c_mz = 'm' + (x - 44); + + char ret = c_mz; + ret = is_dec_19.select(c_19, ret); + ret = is_alpha_AH.select(c_AH, ret); + ret = is_alpha_JN.select(c_JN, ret); + ret = is_alpha_PZ.select(c_PZ, ret); + ret = is_alpha_ak.select(c_ak, ret); + + return ret; + } + +std::string base58_encode(BigInt v, size_t leading_zeros) + { + const uint8_t radix = 58; + + std::string result; + BigInt q; + + while(v.is_nonzero()) + { + uint8_t r; + ct_divide_u8(v, radix, q, r); + result.push_back(lookup_base58_char(r)); + v.swap(q); + } + + for(size_t i = 0; i != leading_zeros; ++i) + result.push_back('1'); // 'zero' byte + + return std::string(result.rbegin(), result.rend()); + } + +template<typename T, typename Z> +size_t count_leading_zeros(const T input[], size_t input_length, Z zero) + { + size_t leading_zeros = 0; + + while(leading_zeros < input_length && input[leading_zeros] == zero) + leading_zeros += 1; + + return leading_zeros; + } + +uint8_t base58_value_of(char input) + { + // "123456789 ABCDEFGH JKLMN PQRSTUVWXYZ abcdefghijk mnopqrstuvwxyz" + + const uint8_t c = static_cast<uint8_t>(input); + + const auto is_dec_19 = CT::Mask<uint8_t>::is_within_range(c, uint8_t('1'), uint8_t('9')); + const auto is_alpha_AH = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('H')); + const auto is_alpha_JN = CT::Mask<uint8_t>::is_within_range(c, uint8_t('J'), uint8_t('N')); + const auto is_alpha_PZ = CT::Mask<uint8_t>::is_within_range(c, uint8_t('P'), uint8_t('Z')); + + const auto is_alpha_ak = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('k')); + const auto is_alpha_mz = CT::Mask<uint8_t>::is_within_range(c, uint8_t('m'), uint8_t('z')); + + const uint8_t c_dec_19 = c - uint8_t('1'); + const uint8_t c_AH = c - uint8_t('A') + 9; + const uint8_t c_JN = c - uint8_t('J') + 17; + const uint8_t c_PZ = c - uint8_t('P') + 22; + + const uint8_t c_ak = c - uint8_t('a') + 33; + const uint8_t c_mz = c - uint8_t('m') + 44; + + uint8_t ret = 0xFF; // default value + + ret = is_dec_19.select(c_dec_19, ret); + ret = is_alpha_AH.select(c_AH, ret); + ret = is_alpha_JN.select(c_JN, ret); + ret = is_alpha_PZ.select(c_PZ, ret); + ret = is_alpha_ak.select(c_ak, ret); + ret = is_alpha_mz.select(c_mz, ret); + return ret; + } + +} + +std::string base58_encode(const uint8_t input[], size_t input_length) + { + BigInt v(input, input_length); + return base58_encode(v, count_leading_zeros(input, input_length, 0)); + } + +std::string base58_check_encode(const uint8_t input[], size_t input_length) + { + BigInt v(input, input_length); + v <<= 32; + v += sha256_d_checksum(input, input_length); + return base58_encode(v, count_leading_zeros(input, input_length, 0)); + } + +std::vector<uint8_t> base58_decode(const char input[], size_t input_length) + { + const size_t leading_zeros = count_leading_zeros(input, input_length, '1'); + + BigInt v; + + for(size_t i = leading_zeros; i != input_length; ++i) + { + const char c = input[i]; + + if(c == ' ' || c == '\n') + continue; + + const uint8_t idx = base58_value_of(c); + + if(idx == 0xFF) + throw Decoding_Error("Invalid base58"); + + v *= 58; + v += idx; + } + + std::vector<uint8_t> output(v.bytes() + leading_zeros); + v.binary_encode(output.data() + leading_zeros); + return output; + } + +std::vector<uint8_t> base58_check_decode(const char input[], size_t input_length) + { + std::vector<uint8_t> dec = base58_decode(input, input_length); + + if(dec.size() < 4) + throw Decoding_Error("Invalid base58 too short for checksum"); + + const uint32_t computed_checksum = sha256_d_checksum(dec.data(), dec.size() - 4); + const uint32_t checksum = load_be<uint32_t>(&dec[dec.size()-4], 0); + + if(checksum != computed_checksum) + throw Decoding_Error("Invalid base58 checksum"); + + dec.resize(dec.size() - 4); + + return dec; + } + +} |