120 lines
3.7 KiB
C
120 lines
3.7 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* gurantee it works.
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*
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* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
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*/
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/* compliant base64 code donated by Wayne Scott (wscott@bitmover.com) */
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#include "mycrypt.h"
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#ifdef BASE64
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static const char *codes =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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static const unsigned char map[256] = {
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 62, 255, 255, 255, 63,
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52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 255, 255,
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255, 254, 255, 255, 255, 0, 1, 2, 3, 4, 5, 6,
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7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
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19, 20, 21, 22, 23, 24, 25, 255, 255, 255, 255, 255,
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255, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36,
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37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
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49, 50, 51, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
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255, 255, 255, 255 };
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int base64_encode(const unsigned char *in, unsigned long len,
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unsigned char *out, unsigned long *outlen)
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{
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unsigned long i, len2, leven;
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unsigned char *p;
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_ARGCHK(in != NULL);
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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/* valid output size ? */
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len2 = 4 * ((len + 2) / 3);
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if (*outlen < len2 + 1) {
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return CRYPT_BUFFER_OVERFLOW;
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}
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p = out;
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leven = 3*(len / 3);
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for (i = 0; i < leven; i += 3) {
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*p++ = codes[in[0] >> 2];
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*p++ = codes[((in[0] & 3) << 4) + (in[1] >> 4)];
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*p++ = codes[((in[1] & 0xf) << 2) + (in[2] >> 6)];
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*p++ = codes[in[2] & 0x3f];
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in += 3;
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}
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/* Pad it if necessary... */
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if (i < len) {
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unsigned a = in[0];
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unsigned b = (i+1 < len) ? in[1] : 0;
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unsigned c = 0;
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*p++ = codes[a >> 2];
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*p++ = codes[((a & 3) << 4) + (b >> 4)];
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*p++ = (i+1 < len) ? codes[((b & 0xf) << 2) + (c >> 6)] : '=';
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*p++ = '=';
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}
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/* append a NULL byte */
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*p = '\0';
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/* return ok */
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*outlen = p - out;
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return CRYPT_OK;
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}
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int base64_decode(const unsigned char *in, unsigned long len,
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unsigned char *out, unsigned long *outlen)
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{
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unsigned long t, x, y, z;
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unsigned char c;
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int g = 3;
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_ARGCHK(in != NULL);
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_ARGCHK(out != NULL);
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_ARGCHK(outlen != NULL);
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for (x = y = z = t = 0; x < len; x++) {
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c = map[in[x]];
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if (c == 255) continue;
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if (c == 254) { c = 0; g--; }
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t = (t<<6)|c;
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if (++y == 4) {
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if (z + g > *outlen) { return CRYPT_BUFFER_OVERFLOW; }
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out[z++] = (unsigned char)((t>>16)&255);
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if (g > 1) out[z++] = (unsigned char)((t>>8)&255);
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if (g > 2) out[z++] = (unsigned char)(t&255);
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y = t = 0;
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}
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}
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if (y != 0) {
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return CRYPT_INVALID_PACKET;
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}
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*outlen = z;
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return CRYPT_OK;
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}
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#endif
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