mirror of
https://github.com/minetest/irrlicht.git
synced 2024-11-05 01:40:44 +01:00
8310a3fbad
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6000 dfc29bdd-3216-0410-991c-e03cc46cb475
139 lines
4.9 KiB
C++
139 lines
4.9 KiB
C++
/*
|
|
---------------------------------------------------------------------------
|
|
Copyright (c) 2002, Dr Brian Gladman < >, Worcester, UK.
|
|
All rights reserved.
|
|
|
|
LICENSE TERMS
|
|
|
|
The free distribution and use of this software in both source and binary
|
|
form is allowed (with or without changes) provided that:
|
|
|
|
1. distributions of this source code include the above copyright
|
|
notice, this list of conditions and the following disclaimer;
|
|
|
|
2. distributions in binary form include the above copyright
|
|
notice, this list of conditions and the following disclaimer
|
|
in the documentation and/or other associated materials;
|
|
|
|
3. the copyright holder's name is not used to endorse products
|
|
built using this software without specific written permission.
|
|
|
|
ALTERNATIVELY, provided that this notice is retained in full, this product
|
|
may be distributed under the terms of the GNU General Public License (GPL),
|
|
in which case the provisions of the GPL apply INSTEAD OF those given above.
|
|
|
|
DISCLAIMER
|
|
|
|
This software is provided 'as is' with no explicit or implied warranties
|
|
in respect of its properties, including, but not limited to, correctness
|
|
and/or fitness for purpose.
|
|
-------------------------------------------------------------------------
|
|
Issue Date: 26/08/2003
|
|
|
|
This file implements password based file encryption and authentication
|
|
using AES in CTR mode, HMAC-SHA1 authentication and RFC2898 password
|
|
based key derivation.
|
|
|
|
*/
|
|
|
|
#include <memory.h>
|
|
|
|
#include "fileenc.h"
|
|
|
|
/* subroutine for data encryption/decryption */
|
|
/* this could be speeded up a lot by aligning */
|
|
/* buffers and using 32 bit operations */
|
|
|
|
static void encr_data(unsigned char data[], unsigned long d_len, fcrypt_ctx cx[1])
|
|
{
|
|
unsigned long i = 0, pos = cx->encr_pos;
|
|
|
|
while(i < d_len)
|
|
{
|
|
if(pos == BLOCK_SIZE)
|
|
{ unsigned int j = 0;
|
|
/* increment encryption nonce */
|
|
while(j < 8 && !++cx->nonce[j])
|
|
++j;
|
|
/* encrypt the nonce to form next xor buffer */
|
|
aes_encrypt(cx->nonce, cx->encr_bfr, cx->encr_ctx);
|
|
pos = 0;
|
|
}
|
|
|
|
data[i++] ^= cx->encr_bfr[pos++];
|
|
}
|
|
|
|
cx->encr_pos = pos;
|
|
}
|
|
|
|
int fcrypt_init(
|
|
int mode, /* the mode to be used (input) */
|
|
const unsigned char pwd[], /* the user specified password (input) */
|
|
unsigned int pwd_len, /* the length of the password (input) */
|
|
const unsigned char salt[], /* the salt (input) */
|
|
#ifdef PASSWORD_VERIFIER
|
|
unsigned char pwd_ver[PWD_VER_LENGTH], /* 2 byte password verifier (output) */
|
|
#endif
|
|
fcrypt_ctx cx[1]) /* the file encryption context (output) */
|
|
{
|
|
unsigned char kbuf[2 * MAX_KEY_LENGTH + PWD_VER_LENGTH];
|
|
|
|
if(pwd_len > MAX_PWD_LENGTH)
|
|
return PASSWORD_TOO_LONG;
|
|
|
|
if(mode < 1 || mode > 3)
|
|
return BAD_MODE;
|
|
|
|
cx->mode = mode;
|
|
cx->pwd_len = pwd_len;
|
|
/* initialise the encryption nonce and buffer pos */
|
|
cx->encr_pos = BLOCK_SIZE;
|
|
|
|
/* if we need a random component in the encryption */
|
|
/* nonce, this is where it would have to be set */
|
|
memset(cx->nonce, 0, BLOCK_SIZE * sizeof(unsigned char));
|
|
/* initialise for authentication */
|
|
hmac_sha_begin(cx->auth_ctx);
|
|
|
|
/* derive the encryption and authetication keys and the password verifier */
|
|
derive_key(pwd, pwd_len, salt, SALT_LENGTH(mode), KEYING_ITERATIONS,
|
|
kbuf, 2 * KEY_LENGTH(mode) + PWD_VER_LENGTH);
|
|
/* set the encryption key */
|
|
aes_encrypt_key(kbuf, KEY_LENGTH(mode), cx->encr_ctx);
|
|
/* set the authentication key */
|
|
hmac_sha_key(kbuf + KEY_LENGTH(mode), KEY_LENGTH(mode), cx->auth_ctx);
|
|
#ifdef PASSWORD_VERIFIER
|
|
memcpy(pwd_ver, kbuf + 2 * KEY_LENGTH(mode), PWD_VER_LENGTH);
|
|
#endif
|
|
/* clear the buffer holding the derived key values */
|
|
memset(kbuf, 0, 2 * KEY_LENGTH(mode) + PWD_VER_LENGTH);
|
|
|
|
return GOOD_RETURN;
|
|
}
|
|
|
|
/* perform 'in place' encryption and authentication */
|
|
|
|
void fcrypt_encrypt(unsigned char data[], unsigned int data_len, fcrypt_ctx cx[1])
|
|
{
|
|
encr_data(data, data_len, cx);
|
|
hmac_sha_data(data, data_len, cx->auth_ctx);
|
|
}
|
|
|
|
/* perform 'in place' authentication and decryption */
|
|
|
|
void fcrypt_decrypt(unsigned char data[], unsigned int data_len, fcrypt_ctx cx[1])
|
|
{
|
|
hmac_sha_data(data, data_len, cx->auth_ctx);
|
|
encr_data(data, data_len, cx);
|
|
}
|
|
|
|
/* close encryption/decryption and return the MAC value */
|
|
|
|
int fcrypt_end(unsigned char mac[], fcrypt_ctx cx[1])
|
|
{
|
|
hmac_sha_end(mac, MAC_LENGTH(cx->mode), cx->auth_ctx);
|
|
memset(cx, 0, sizeof(fcrypt_ctx)); /* clear the encryption context */
|
|
return MAC_LENGTH(cx->mode); /* return MAC length in bytes */
|
|
}
|
|
|