base58.c File Reference

#include "btc/base58.h"
#include <string.h>
#include <sys/types.h>
#include "sha2.h"

Go to the source code of this file.

Functions
int	btc_base58_decode (void *bin, size_t *binszp, const char *b58)
int	btc_b58check (const void *bin, size_t binsz, const char *base58str)
int	btc_base58_encode (char *b58, size_t *b58sz, const void *data, size_t binsz)
int	btc_base58_encode_check (const uint8_t *data, int datalen, char *str, int strsize)
int	btc_base58_decode_check (const char *str, uint8_t *data, size_t datalen)

Variables
static const int8_t	b58digits_map []
static const char	b58digits_ordered []

Function Documentation

int btc_b58check	(	const void *	bin,
		size_t	binsz,
		const char *	base58str
	)

Definition at line 127 of file base58.c.

References sha256_Raw().

Referenced by btc_base58_decode_check().

{
    unsigned char buf[32];
    const uint8_t *binc = bin;
    unsigned i;
    if (binsz < 4) {
        return -4;
    }
    sha256_Raw(bin, binsz - 4, buf);
    sha256_Raw(buf, 32, 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];
}

int btc_base58_decode	(	void *	bin,
		size_t *	binszp,
		const char *	b58
	)

Definition at line 42 of file base58.c.

References b58digits_map.

Referenced by btc_base58_decode_check().

{
    size_t binsz = *binszp;
    const unsigned char *b58u = (const void *)b58;
    unsigned char *binu = bin;
    size_t outisz = (binsz + 3) / 4;
    uint32_t outi[outisz];
    uint64_t t;
    uint32_t c;
    size_t i, j;
    uint8_t bytesleft = binsz % 4;
    uint32_t zeromask = bytesleft ? (0xffffffff << (bytesleft * 8)) : 0;
    unsigned zerocount = 0;
    size_t b58sz;

    b58sz = strlen(b58);

    memset(outi, 0, outisz * sizeof(*outi));

    // Leading zeros, just count
    for (i = 0; i < b58sz && !b58digits_map[b58u[i]]; ++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 = ((uint64_t)outi[j]) * 58 + c;
            c = (t & 0x3f00000000) >> 32;
            outi[j] = t & 0xffffffff;
        }
        if (c) {
            // Output number too big (carry to the next int32)
            memset(outi, 0, outisz * sizeof(*outi));
            return false;
        }
        if (outi[0] & zeromask) {
            // Output number too big (last int32 filled too far)
            memset(outi, 0, outisz * sizeof(*outi));
            return false;
        }
    }

    j = 0;
    switch (bytesleft) {
        case 3:
            *(binu++) = (outi[0] &   0xff0000) >> 16;
        case 2:
            *(binu++) = (outi[0] &     0xff00) >>  8;
        case 1:
            *(binu++) = (outi[0] &       0xff);
            ++j;
        default:
            break;
    }

    for (; j < outisz; ++j) {
        *(binu++) = (outi[j] >> 0x18) & 0xff;
        *(binu++) = (outi[j] >> 0x10) & 0xff;
        *(binu++) = (outi[j] >>    8) & 0xff;
        *(binu++) = (outi[j] >>    0) & 0xff;
    }

    // Count canonical base58 byte count
    binu = bin;
    for (i = 0; i < binsz; ++i) {
        if (binu[i]) {
            break;
        }
        --*binszp;
    }
    *binszp += zerocount;

    memset(outi, 0, outisz * sizeof(*outi));
    return true;
}

int btc_base58_decode_check	(	const char *	str,
		uint8_t *	data,
		size_t	datalen
	)

Definition at line 219 of file base58.c.

References btc_b58check(), and btc_base58_decode().

Referenced by btc_hdnode_deserialize(), and btc_tx_add_address_out().

{
    int ret;
    size_t strl = strlen(str);

    /* buffer needs to be at least the strsize, will be used
       for the whole decoding */
    if (strl > 128 || datalen < strl) {
        return 0;
    }

    size_t binsize = strl;
    if (btc_base58_decode(data, &binsize, str) != true) {
        ret = 0;
    }

    memmove(data, data+strl-binsize, binsize);
    memset(data+binsize, 0, datalen-binsize);

    if (btc_b58check(data, binsize, str) < 0) {
        ret = 0;
    } else {
        ret = binsize;
    }
    return ret;
}

int btc_base58_encode	(	char *	b58,
		size_t *	b58sz,
		const void *	data,
		size_t	binsz
	)

Definition at line 154 of file base58.c.

References b58digits_ordered.

Referenced by btc_base58_encode_check().

{
    const uint8_t *bin = data;
    int carry;
    ssize_t i, j, high, zcount = 0;
    size_t size;

    while (zcount < (ssize_t)binsz && !bin[zcount]) {
        ++zcount;
    }

    size = (binsz - zcount) * 138 / 100 + 1;
    uint8_t buf[size];
    memset(buf, 0, size);

    for (i = zcount, high = size - 1; i < (ssize_t)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;
        }
    }

    for (j = 0; j < (ssize_t)size && !buf[j]; ++j);

    if (*b58sz <= zcount + size - j) {
        *b58sz = zcount + size - j + 1;
        memset(buf, 0, size);
        return false;
    }

    if (zcount) {
        memset(b58, '1', zcount);
    }
    for (i = zcount; j < (ssize_t)size; ++i, ++j) {
        b58[i] = b58digits_ordered[buf[j]];
    }
    b58[i] = '\0';
    *b58sz = i + 1;

    memset(buf, 0, size);
    return true;
}

int btc_base58_encode_check	(	const uint8_t *	data,
		int	len,
		char *	str,
		int	strsize
	)

Copyright (c) 2013-2014 Tomas Dzetkulic 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.

Definition at line 198 of file base58.c.

References btc_base58_encode(), and sha256_Raw().

Referenced by btc_hdnode_serialize().

{
    int ret;
    if (datalen > 128) {
        return 0;
    }
    uint8_t buf[datalen + 32];
    uint8_t *hash = buf + datalen;
    memcpy(buf, data, datalen);
    sha256_Raw(data, datalen, hash);
    sha256_Raw(hash, 32, hash);
    size_t res = strsize;
    if (btc_base58_encode(str, &res, buf, datalen + 4) != true) {
        ret = 0;
    } else {
        ret = res;
    }
    memset(buf, 0, sizeof(buf));
    return ret;
}

Variable Documentation

const int8_t b58digits_map[]

static

Initial value:

= {
    -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,
}

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.

Definition at line 31 of file base58.c.

Referenced by btc_base58_decode().

const char b58digits_ordered[]

static

Initial value:

=
    "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"

Definition at line 151 of file base58.c.

Referenced by btc_base58_encode().