/** * Copyright (c) 2012-2014 Luke Dashjr * Copyright (c) 2013-2014 Pavol Rusnak * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. */ #include "base58.h" #include <stdbool.h> #include <string.h> #include "memzero.h" #include "ripemd160.h" #include "sha2.h" const char b58digits_ordered[] = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"; const int8_t b58digits_map[] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, -1, -1, -1, -1, -1, -1, -1, 9, 10, 11, 12, 13, 14, 15, 16, -1, 17, 18, 19, 20, 21, -1, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, -1, -1, -1, -1, -1, -1, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, -1, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, -1, -1, -1, -1, -1, }; typedef uint64_t b58_maxint_t; typedef uint32_t b58_almostmaxint_t; #define b58_almostmaxint_bits (sizeof(b58_almostmaxint_t) * 8) static const b58_almostmaxint_t b58_almostmaxint_mask = ((((b58_maxint_t)1) << b58_almostmaxint_bits) - 1); // Decodes a null-terminated Base58 string `b58` to binary and writes the result // at the end of the buffer `bin` of size `*binszp`. On success `*binszp` is set // to the number of valid bytes at the end of the buffer. bool b58tobin(void *bin, size_t *binszp, const char *b58) { size_t binsz = *binszp; if (binsz == 0) { return false; } const unsigned char *b58u = (const unsigned char *)b58; unsigned char *binu = bin; size_t outisz = (binsz + sizeof(b58_almostmaxint_t) - 1) / sizeof(b58_almostmaxint_t); b58_almostmaxint_t outi[outisz]; b58_maxint_t t = 0; b58_almostmaxint_t c = 0; size_t i = 0, j = 0; uint8_t bytesleft = binsz % sizeof(b58_almostmaxint_t); b58_almostmaxint_t zeromask = bytesleft ? (b58_almostmaxint_mask << (bytesleft * 8)) : 0; unsigned zerocount = 0; size_t b58sz = strlen(b58); memzero(outi, sizeof(outi)); // Leading zeros, just count for (i = 0; i < b58sz && b58u[i] == '1'; ++i) ++zerocount; for (; i < b58sz; ++i) { if (b58u[i] & 0x80) // High-bit set on invalid digit return false; if (b58digits_map[b58u[i]] == -1) // Invalid base58 digit return false; c = (unsigned)b58digits_map[b58u[i]]; for (j = outisz; j--;) { t = ((b58_maxint_t)outi[j]) * 58 + c; c = t >> b58_almostmaxint_bits; outi[j] = t & b58_almostmaxint_mask; } if (c) // Output number too big (carry to the next int32) return false; if (outi[0] & zeromask) // Output number too big (last int32 filled too far) return false; } j = 0; if (bytesleft) { for (i = bytesleft; i > 0; --i) { *(binu++) = (outi[0] >> (8 * (i - 1))) & 0xff; } ++j; } for (; j < outisz; ++j) { for (i = sizeof(*outi); i > 0; --i) { *(binu++) = (outi[j] >> (8 * (i - 1))) & 0xff; } } // locate the most significant byte binu = bin; for (i = 0; i < binsz; ++i) { if (binu[i]) break; } // prepend the correct number of null-bytes if (zerocount > i) { /* result too large */ return false; } *binszp = binsz - i + zerocount; return true; } int b58check(const void *bin, size_t binsz, HasherType hasher_type, const char *base58str) { unsigned char buf[32] = {0}; const uint8_t *binc = bin; unsigned i = 0; if (binsz < 4) return -4; hasher_Raw(hasher_type, bin, binsz - 4, buf); if (memcmp(&binc[binsz - 4], buf, 4)) return -1; // Check number of zeros is correct AFTER verifying checksum (to avoid // possibility of accessing base58str beyond the end) for (i = 0; binc[i] == '\0' && base58str[i] == '1'; ++i) { } // Just finding the end of zeros, nothing to do in loop if (binc[i] == '\0' || base58str[i] == '1') return -3; return binc[0]; } bool b58enc(char *b58, size_t *b58sz, const void *data, size_t binsz) { const uint8_t *bin = data; int carry = 0; size_t i = 0, j = 0, high = 0, zcount = 0; size_t size = 0; while (zcount < binsz && !bin[zcount]) ++zcount; size = (binsz - zcount) * 138 / 100 + 1; uint8_t buf[size]; memzero(buf, size); for (i = zcount, high = size - 1; i < binsz; ++i, high = j) { for (carry = bin[i], j = size - 1; (j > high) || carry; --j) { carry += 256 * buf[j]; buf[j] = carry % 58; carry /= 58; if (!j) { // Otherwise j wraps to maxint which is > high break; } } } for (j = 0; j < size && !buf[j]; ++j) ; if (*b58sz <= zcount + size - j) { *b58sz = zcount + size - j + 1; return false; } if (zcount) memset(b58, '1', zcount); for (i = zcount; j < size; ++i, ++j) b58[i] = b58digits_ordered[buf[j]]; b58[i] = '\0'; *b58sz = i + 1; return true; } int base58_encode_check(const uint8_t *data, int datalen, HasherType hasher_type, char *str, int strsize) { if (datalen > 128) { return 0; } uint8_t buf[datalen + 32]; memset(buf, 0, sizeof(buf)); uint8_t *hash = buf + datalen; memcpy(buf, data, datalen); hasher_Raw(hasher_type, data, datalen, hash); size_t res = strsize; bool success = b58enc(str, &res, buf, datalen + 4); memzero(buf, sizeof(buf)); return success ? res : 0; } int base58_decode_check(const char *str, HasherType hasher_type, uint8_t *data, int datalen) { if (datalen > 128) { return 0; } uint8_t d[datalen + 4]; memset(d, 0, sizeof(d)); size_t res = datalen + 4; if (b58tobin(d, &res, str) != true) { return 0; } uint8_t *nd = d + datalen + 4 - res; if (b58check(nd, res, hasher_type, str) < 0) { return 0; } memcpy(data, nd, res - 4); return res - 4; }