radare2/libr/crypto/p/crypto_rot.c
2019-06-13 19:12:51 +02:00

108 lines
2.4 KiB
C

/* radare - LGPL - Copyright 2009-2017 - pancake */
#include <r_lib.h>
#include <r_crypto.h>
int mod(int a, int b) {
if (b < 0) {
return mod (-a, -b);
}
int ret = a % b;
if (ret < 0) {
ret += b;
}
return ret;
}
static bool rot_init(ut8 *rotkey, const ut8 *key, int keylen) {
if (rotkey && key && keylen > 0) {
int i = atoi ((const char *)key);
*rotkey = (ut8)mod (i, 26);
return true;
}
return false;
}
static void rot_crypt(ut8 key, const ut8 *inbuf, ut8 *outbuf, int buflen) {
int i;
for (i = 0; i < buflen; i++) {
outbuf[i] = inbuf[i];
if ((inbuf[i] < 'a' || inbuf[i] > 'z') && (inbuf[i] < 'A' || inbuf[i] > 'Z')) {
continue;
}
outbuf[i] += key;
outbuf[i] -= (inbuf[i] >= 'a' && inbuf[i] <= 'z') ? 'a' : 'A';
outbuf[i] = mod (outbuf[i], 26);
outbuf[i] += (inbuf[i] >= 'a' && inbuf[i] <= 'z') ? 'a' : 'A';
}
}
static void rot_decrypt(ut8 key, const ut8 *inbuf, ut8 *outbuf, int buflen) {
int i;
for (i = 0; i < buflen; i++) {
outbuf[i] = inbuf[i];
if ((inbuf[i] < 'a' || inbuf[i] > 'z') && (inbuf[i] < 'A' || inbuf[i] > 'Z')) {
continue;
}
outbuf[i] += 26; //adding so that subtracting does not make it negative
outbuf[i] -= key;
outbuf[i] -= (inbuf[i] >= 'a' && inbuf[i] <= 'z') ? 'a' : 'A';
outbuf[i] = mod (outbuf[i], 26);
outbuf[i] += (inbuf[i] >= 'a' && inbuf[i] <= 'z') ? 'a' : 'A';
}
}
static ut8 rot_key;
static int flag = 0;
static bool rot_set_key(RCrypto *cry, const ut8 *key, int keylen, int mode, int direction) {
flag = direction;
return rot_init (&rot_key, key, keylen);
}
static int rot_get_key_size(RCrypto *cry) {
//Returning number of bytes occupied by ut8
return 1;
}
static bool rot_use(const char *algo) {
return !strcmp (algo, "rot");
}
static bool update(RCrypto *cry, const ut8 *buf, int len) {
ut8 *obuf = calloc (1, len);
if (!obuf) {
return false;
}
if (flag == 0) {
rot_crypt (rot_key, buf, obuf, len);
} else if (flag == 1) {
rot_decrypt (rot_key, buf, obuf, len);
}
r_crypto_append (cry, obuf, len);
free (obuf);
return true;
}
static bool final(RCrypto *cry, const ut8 *buf, int len) {
return update (cry, buf, len);
}
RCryptoPlugin r_crypto_plugin_rot = {
.name = "rot",
.set_key = rot_set_key,
.get_key_size = rot_get_key_size,
.use = rot_use,
.update = update,
.final = final
};
#ifndef R2_PLUGIN_INCORE
R_API RLibStruct radare_plugin = {
.type = R_LIB_TYPE_CRYPTO,
.data = &r_crypto_plugin_rot,
.version = R2_VERSION
};
#endif