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/* Copyright (c) 2017 Pieter 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 <stdlib.h>
#include <stdint.h>
#include <string.h>
#include "segwit_addr.h"
uint32_t bech32_polymod_step(uint32_t pre) {
uint8_t b = pre >> 25;
return ((pre & 0x1FFFFFF) << 5) ^
(-((b >> 0) & 1) & 0x3b6a57b2UL) ^
(-((b >> 1) & 1) & 0x26508e6dUL) ^
(-((b >> 2) & 1) & 0x1ea119faUL) ^
(-((b >> 3) & 1) & 0x3d4233ddUL) ^
(-((b >> 4) & 1) & 0x2a1462b3UL);
}
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 bech32_encode(char *output, const char *hrp, const uint8_t *data, size_t data_len) {
uint32_t chk = 1;
size_t i = 0;
while (hrp[i] != 0) {
int ch = hrp[i];
if (ch < 33 || ch > 126) {
return 0;
}
if (ch >= 'A' && ch <= 'Z') return 0;
chk = bech32_polymod_step(chk) ^ (ch >> 5);
++i;
}
if (i + 7 + data_len > 90) return 0;
chk = bech32_polymod_step(chk);
while (*hrp != 0) {
chk = bech32_polymod_step(chk) ^ (*hrp & 0x1f);
*(output++) = *(hrp++);
}
*(output++) = '1';
for (i = 0; i < data_len; ++i) {
if (*data >> 5) return 0;
chk = bech32_polymod_step(chk) ^ (*data);
*(output++) = charset[*(data++)];
}
for (i = 0; i < 6; ++i) {
chk = bech32_polymod_step(chk);
}
chk ^= 1;
for (i = 0; i < 6; ++i) {
*(output++) = charset[(chk >> ((5 - i) * 5)) & 0x1f];
}
*output = 0;
return 1;
}
int bech32_decode(char* hrp, uint8_t *data, size_t *data_len, const char *input) {
uint32_t chk = 1;
size_t i;
size_t input_len = strlen(input);
size_t hrp_len;
int have_lower = 0, have_upper = 0;
if (input_len < 8 || input_len > 90) {
return 0;
}
*data_len = 0;
while (*data_len < input_len && input[(input_len - 1) - *data_len] != '1') {
++(*data_len);
}
hrp_len = input_len - (1 + *data_len);
if (hrp_len < 1 || *data_len < 6) {
return 0;
}
*(data_len) -= 6;
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 = bech32_polymod_step(chk) ^ (ch >> 5);
}
hrp[i] = 0;
chk = bech32_polymod_step(chk);
for (i = 0; i < hrp_len; ++i) {
chk = bech32_polymod_step(chk) ^ (input[i] & 0x1f);
}
++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 = bech32_polymod_step(chk) ^ v;
if (i + 6 < 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 segwit_addr_encode(char *output, const char *hrp, int witver, const uint8_t *witprog, size_t witprog_len) {
uint8_t data[65];
size_t datalen = 0;
if (witver > 16) return 0;
if (witver == 0 && witprog_len != 20 && witprog_len != 32) return 0;
if (witprog_len < 2 || witprog_len > 40) return 0;
data[0] = witver;
convert_bits(data + 1, &datalen, 5, witprog, witprog_len, 8, 1);
++datalen;
return bech32_encode(output, hrp, data, datalen);
}
int segwit_addr_decode(int* witver, uint8_t* witdata, size_t* witdata_len, const char* hrp, const char* addr) {
uint8_t data[84];
char hrp_actual[84];
size_t data_len;
if (!bech32_decode(hrp_actual, data, &data_len, addr)) return 0;
if (data_len == 0 || data_len > 65) return 0;
if (strncmp(hrp, hrp_actual, 84) != 0) return 0;
if (data[0] > 16) return 0;
*witdata_len = 0;
if (!convert_bits(witdata, witdata_len, 8, data + 1, data_len - 1, 5, 0)) return 0;
if (*witdata_len < 2 || *witdata_len > 40) return 0;
if (data[0] == 0 && *witdata_len != 20 && *witdata_len != 32) return 0;
*witver = data[0];
return 1;
}