int
cryDes3UtilDecrypt(const char *sInBuf, int iInLen, char *sOutBuf, int *piOutLen,
const char sKey[24])
{
des3_context tCtx;
if (*piOutLen < (iInLen / 8 + (iInLen % 8 == 0 ? 0 : 1)) * 8)
return -1;
des3_set3key_dec(&tCtx, (unsigned char *)sKey);
*piOutLen = 0;
while (iInLen > 0) {
if (iInLen >= 8)
des3_crypt_ecb(&tCtx, (unsigned char *)sInBuf + *piOutLen,
(unsigned char *)sOutBuf + *piOutLen);
else {
memcpy(sOutBuf + *piOutLen, sInBuf + *piOutLen, iInLen);
memset(sOutBuf + *piOutLen + iInLen, 0, 8 - iInLen);
des3_crypt_ecb(&tCtx, (unsigned char *)sOutBuf + *piOutLen,
(unsigned char *)sOutBuf + *piOutLen);
}
*piOutLen += 8;
iInLen = iInLen > 8 ? iInLen - 8 : 0;
}
return 0;
}
static mrb_value mrb_des3_decrypt(mrb_state *mrb, mrb_value self) {
mrb_value mode, key, source, dest, iv;
unsigned char output[100];
des3_context ctx;
mrb_int len=16;
memset(output, 0, sizeof(output));
mrb_get_args(mrb, "SSSS", &mode, &key, &source, &iv);
des3_init(&ctx);
if (RSTRING_LEN(key) == 16) {
des3_set2key_dec(&ctx, RSTRING_PTR(key));
} else if (RSTRING_LEN(key) == 24) {
des3_set3key_dec(&ctx, RSTRING_PTR(key));
} else {
des3_free(&ctx);
return mrb_nil_value();
}
if (mrb_str_cmp(mrb, mode, mrb_str_new(mrb, "CBC", 3)) == 0) {
des3_crypt_cbc(&ctx, DES_DECRYPT, RSTRING_LEN(source), RSTRING_PTR(iv),
RSTRING_PTR(source), output);
len = RSTRING_LEN(source);
} else if (mrb_str_cmp(mrb, mode, mrb_str_new(mrb, "ECB", 3)) == 0) {
des3_crypt_ecb(&ctx, RSTRING_PTR(source), output);
len = 8;
} else {
des3_free(&ctx);
return mrb_nil_value();
}
des3_free(&ctx);
return mrb_str_new(mrb, output, len);
}
static int des3_crypt_ecb_wrap( void *ctx, operation_t operation,
const unsigned char *input, unsigned char *output )
{
((void) operation);
return des3_crypt_ecb( (des3_context *) ctx, input, output );
}
