Bech32 (BIP173) address support

Makefile

@@ -50,6 +50,7 @@ SRCS  += blake2b.c blake2s.c
 SRCS  += chacha20poly1305/chacha20poly1305.c chacha20poly1305/chacha_merged.c chacha20poly1305/poly1305-donna.c chacha20poly1305/rfc7539.c
 SRCS  += rc4.c
 SRCS  += nem.c
+SRCS  += segwit_addr.c
 
 OBJS   = $(SRCS:.c=.o)
 

ecdsa.h

@@ -48,10 +48,16 @@ typedef struct {
 
 } ecdsa_curve;
 
+// 4 byte prefix + 40 byte data (segwit)
 #define MAX_ADDR_RAW_SIZE (4 + 40)
+// bottle neck is segwit bech32:
+// 4 human readable prefix + 1 separator + 64 data + 6 checksum + 1 NUL
+// the standard says 83 characters in hrp, but currently all coins use only 2
+#define MAX_ADDR_SIZE (4+1+64+6+1)
+// 4 byte prefix + 32 byte privkey + 1 byte compressed marker
 #define MAX_WIF_RAW_SIZE (4 + 32 + 1)
-#define MAX_ADDR_SIZE (54)
-#define MAX_WIF_SIZE (58)
+// (4+32+1 + 4 [checksum]) * 8 / log2(58) plus NUL.
+#define MAX_WIF_SIZE (57)
 
 void point_copy(const curve_point *cp1, curve_point *cp2);
 void point_add(const ecdsa_curve *curve, const curve_point *cp1, curve_point *cp2);

segwit_addr.c

@@ -0,0 +1,191 @@
+/* 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;
+}

segwit_addr.h

@@ -0,0 +1,101 @@
+/* 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.
+ */
+
+#ifndef _SEGWIT_ADDR_H_
+#define _SEGWIT_ADDR_H_ 1
+
+#include <stdint.h>
+
+/** Encode a SegWit address
+ *
+ *  Out: output:   Pointer to a buffer of size 73 + strlen(hrp) that will be
+ *                 updated to contain the null-terminated address.
+ *  In:  hrp:      Pointer to the null-terminated human readable part to use
+ *                 (chain/network specific).
+ *       ver:      Version of the witness program (between 0 and 16 inclusive).
+ *       prog:     Data bytes for the witness program (between 2 and 40 bytes).
+ *       prog_len: Number of data bytes in prog.
+ *  Returns 1 if successful.
+ */
+int segwit_addr_encode(
+    char *output,
+    const char *hrp,
+    int ver,
+    const uint8_t *prog,
+    size_t prog_len
+);
+
+/** Decode a SegWit address
+ *
+ *  Out: ver:      Pointer to an int that will be updated to contain the witness
+ *                 program version (between 0 and 16 inclusive).
+ *       prog:     Pointer to a buffer of size 40 that will be updated to
+ *                 contain the witness program bytes.
+ *       prog_len: Pointer to a size_t that will be updated to contain the length
+ *                 of bytes in prog.
+ *       hrp:      Pointer to the null-terminated human readable part that is
+ *                 expected (chain/network specific).
+ *       addr:     Pointer to the null-terminated address.
+ *  Returns 1 if successful.
+ */
+int segwit_addr_decode(
+    int* ver,
+    uint8_t* prog,
+    size_t* prog_len,
+    const char* hrp,
+    const char* addr
+);
+
+/** Encode a Bech32 string
+ *
+ *  Out: output:  Pointer to a buffer of size strlen(hrp) + data_len + 8 that
+ *                will be updated to contain the null-terminated Bech32 string.
+ *  In: hrp :     Pointer to the null-terminated human readable part.
+ *      data :    Pointer to an array of 5-bit values.
+ *      data_len: Length of the data array.
+ *  Returns 1 if successful.
+ */
+int bech32_encode(
+    char *output,
+    const char *hrp,
+    const uint8_t *data,
+    size_t data_len
+);
+
+/** Decode a Bech32 string
+ *
+ *  Out: hrp:      Pointer to a buffer of size strlen(input) - 6. Will be
+ *                 updated to contain the null-terminated human readable part.
+ *       data:     Pointer to a buffer of size strlen(input) - 8 that will
+ *                 hold the encoded 5-bit data values.
+ *       data_len: Pointer to a size_t that will be updated to be the number
+ *                 of entries in data.
+ *  In: input:     Pointer to a null-terminated Bech32 string.
+ *  Returns 1 if succesful.
+ */
+int bech32_decode(
+    char *hrp,
+    uint8_t *data,
+    size_t *data_len,
+    const char *input
+);
+
+#endif

test_check.c

@@ -4053,6 +4053,8 @@ START_TEST(test_rc4_rfc6229)
 }
 END_TEST
 
+#include "test_segwit.c"
+
 // define test suite and cases
 Suite *test_suite(void)
 {
@@ -4266,6 +4268,10 @@ Suite *test_suite(void)
 	tcase_add_test(tc, test_rc4_rfc6229);
 	suite_add_tcase(s, tc);
 
+	tc = tcase_create("segwit");
+	tcase_add_test(tc, test_segwit);
+	suite_add_tcase(s, tc);
+
 	return s;
 }