/* Copyright (c) 2017 Jochen Hoenicke * based on code Copyright (c) 2017 Peter Wuille * * 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 <stdint.h> #include <stdlib.h> #include <string.h> #include "cash_addr.h" #define MAX_CASHADDR_SIZE 129 #define MAX_BASE32_SIZE 104 #define MAX_DATA_SIZE 65 #define MAX_HRP_SIZE 20 #define CHECKSUM_SIZE 8 uint64_t cashaddr_polymod_step(uint64_t pre) { uint8_t b = pre >> 35; return ((pre & 0x7FFFFFFFFULL) << 5) ^ (-((b >> 0) & 1) & 0x98f2bc8e61ULL) ^ (-((b >> 1) & 1) & 0x79b76d99e2ULL) ^ (-((b >> 2) & 1) & 0xf33e5fb3c4ULL) ^ (-((b >> 3) & 1) & 0xae2eabe2a8ULL) ^ (-((b >> 4) & 1) & 0x1e4f43e470ULL); } static const char* charset = "qpzry9x8gf2tvdw0s3jn54khce6mua7l"; static const int8_t charset_rev[128] = { -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, 15, -1, 10, 17, 21, 20, 26, 30, 7, 5, -1, -1, -1, -1, -1, -1, -1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1, 1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1, -1, 29, -1, 24, 13, 25, 9, 8, 23, -1, 18, 22, 31, 27, 19, -1, 1, 0, 3, 16, 11, 28, 12, 14, 6, 4, 2, -1, -1, -1, -1, -1}; int cash_encode(char* output, const char* hrp, const uint8_t* data, size_t data_len) { uint64_t chk = 1; size_t i = 0; while (hrp[i] != 0) { int ch = hrp[i]; if (ch < 33 || ch > 126) { return 0; } *(output++) = ch; chk = cashaddr_polymod_step(chk) ^ (ch & 0x1f); ++i; } if (i + 1 + data_len + CHECKSUM_SIZE > MAX_CASHADDR_SIZE) { return 0; } chk = cashaddr_polymod_step(chk); *(output++) = ':'; for (i = 0; i < data_len; ++i) { if (*data >> 5) return 0; chk = cashaddr_polymod_step(chk) ^ (*data); *(output++) = charset[*(data++)]; } for (i = 0; i < CHECKSUM_SIZE; ++i) { chk = cashaddr_polymod_step(chk); } chk ^= 1; for (i = 0; i < CHECKSUM_SIZE; ++i) { *(output++) = charset[(chk >> ((CHECKSUM_SIZE - 1 - i) * 5)) & 0x1f]; } *output = 0; return 1; } int cash_decode(char* hrp, uint8_t* data, size_t* data_len, const char* input) { uint64_t chk = 1; size_t i = 0; size_t input_len = strlen(input); size_t hrp_len = 0; int have_lower = 0, have_upper = 0; if (input_len < CHECKSUM_SIZE || input_len > MAX_CASHADDR_SIZE) { return 0; } *data_len = 0; while (*data_len < input_len && input[(input_len - 1) - *data_len] != ':') { ++(*data_len); } hrp_len = input_len - (1 + *data_len); if (1 + *data_len >= input_len || hrp_len > MAX_HRP_SIZE || *data_len < CHECKSUM_SIZE || *data_len > CHECKSUM_SIZE + MAX_BASE32_SIZE) { return 0; } // subtract checksum *(data_len) -= CHECKSUM_SIZE; for (i = 0; i < hrp_len; ++i) { int ch = input[i]; if (ch < 33 || ch > 126) { return 0; } if (ch >= 'a' && ch <= 'z') { have_lower = 1; } else if (ch >= 'A' && ch <= 'Z') { have_upper = 1; ch = (ch - 'A') + 'a'; } hrp[i] = ch; chk = cashaddr_polymod_step(chk) ^ (ch & 0x1f); } hrp[i] = 0; chk = cashaddr_polymod_step(chk); ++i; while (i < input_len) { int v = (input[i] & 0x80) ? -1 : charset_rev[(int)input[i]]; if (input[i] >= 'a' && input[i] <= 'z') have_lower = 1; if (input[i] >= 'A' && input[i] <= 'Z') have_upper = 1; if (v == -1) { return 0; } chk = cashaddr_polymod_step(chk) ^ v; if (i + CHECKSUM_SIZE < input_len) { data[i - (1 + hrp_len)] = v; } ++i; } if (have_lower && have_upper) { return 0; } return chk == 1; } static int convert_bits(uint8_t* out, size_t* outlen, int outbits, const uint8_t* in, size_t inlen, int inbits, int pad) { uint32_t val = 0; int bits = 0; uint32_t maxv = (((uint32_t)1) << outbits) - 1; while (inlen--) { val = (val << inbits) | *(in++); bits += inbits; while (bits >= outbits) { bits -= outbits; out[(*outlen)++] = (val >> bits) & maxv; } } if (pad) { if (bits) { out[(*outlen)++] = (val << (outbits - bits)) & maxv; } } else if (((val << (outbits - bits)) & maxv) || bits >= inbits) { return 0; } return 1; } int cash_addr_encode(char* output, const char* hrp, const uint8_t* data, size_t data_len) { uint8_t base32[MAX_BASE32_SIZE] = {0}; size_t base32len = 0; if (data_len < 2 || data_len > MAX_DATA_SIZE) return 0; convert_bits(base32, &base32len, 5, data, data_len, 8, 1); return cash_encode(output, hrp, base32, base32len); } int cash_addr_decode(uint8_t* witdata, size_t* witdata_len, const char* hrp, const char* addr) { uint8_t data[MAX_BASE32_SIZE] = {0}; char hrp_actual[MAX_HRP_SIZE + 1] = {0}; size_t data_len = 0; if (!cash_decode(hrp_actual, data, &data_len, addr)) return 0; if (data_len == 0 || data_len > MAX_BASE32_SIZE) return 0; if (strncmp(hrp, hrp_actual, MAX_HRP_SIZE + 1) != 0) return 0; *witdata_len = 0; if (!convert_bits(witdata, witdata_len, 8, data, data_len, 5, 0)) return 0; if (*witdata_len < 2 || *witdata_len > MAX_DATA_SIZE) return 0; return 1; }