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/*
* Copyright (C) 2013 Tobias Brunner
* Hochschule fuer Technik Rapperswil
*
* Copyright (C) 2010 Martin Willi
* Copyright (C) 2010 revosec AG
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*/
#include "aead.h"
#include <utils/debug.h>
#include <crypto/iv/iv_gen_rand.h>
typedef struct private_aead_t private_aead_t;
/**
* Private data of an aead_t object.
*/
struct private_aead_t {
/**
* Public aead_t interface.
*/
aead_t public;
/**
* traditional crypter
*/
crypter_t *crypter;
/**
* traditional signer
*/
signer_t *signer;
/**
* IV generator
*/
iv_gen_t *iv_gen;
};
METHOD(aead_t, encrypt, bool,
private_aead_t *this, chunk_t plain, chunk_t assoc, chunk_t iv,
chunk_t *encrypted)
{
chunk_t encr, sig;
if (!this->signer->get_signature(this->signer, assoc, NULL) ||
!this->signer->get_signature(this->signer, iv, NULL))
{
return FALSE;
}
if (encrypted)
{
if (!this->crypter->encrypt(this->crypter, plain, iv, &encr))
{
return FALSE;
}
if (!this->signer->allocate_signature(this->signer, encr, &sig))
{
free(encr.ptr);
return FALSE;
}
*encrypted = chunk_cat("cmm", iv, encr, sig);
}
else
{
if (!this->crypter->encrypt(this->crypter, plain, iv, NULL) ||
!this->signer->get_signature(this->signer,
plain, plain.ptr + plain.len))
{
return FALSE;
}
}
return TRUE;
}
METHOD(aead_t, decrypt, bool,
private_aead_t *this, chunk_t encrypted, chunk_t assoc, chunk_t iv,
chunk_t *plain)
{
chunk_t sig;
size_t bs;
bs = this->crypter->get_block_size(this->crypter);
sig.len = this->signer->get_block_size(this->signer);
if (sig.len > encrypted.len || (encrypted.len - sig.len) % bs)
{
DBG1(DBG_LIB, "invalid encrypted data length %d with block size %d",
encrypted.len - sig.len, bs);
return FALSE;
}
chunk_split(encrypted, "mm", encrypted.len - sig.len,
&encrypted, sig.len, &sig);
if (!this->signer->get_signature(this->signer, assoc, NULL) ||
!this->signer->get_signature(this->signer, iv, NULL))
{
return FALSE;
}
if (!this->signer->verify_signature(this->signer, encrypted, sig))
{
DBG1(DBG_LIB, "MAC verification failed");
return FALSE;
}
return this->crypter->decrypt(this->crypter, encrypted, iv, plain);
}
METHOD(aead_t, get_block_size, size_t,
private_aead_t *this)
{
return this->crypter->get_block_size(this->crypter);
}
METHOD(aead_t, get_icv_size, size_t,
private_aead_t *this)
{
return this->signer->get_block_size(this->signer);
}
METHOD(aead_t, get_iv_size, size_t,
private_aead_t *this)
{
return this->crypter->get_iv_size(this->crypter);
}
METHOD(aead_t, get_iv_gen, iv_gen_t*,
private_aead_t *this)
{
return this->iv_gen;
}
METHOD(aead_t, get_key_size, size_t,
private_aead_t *this)
{
return this->crypter->get_key_size(this->crypter) +
this->signer->get_key_size(this->signer);
}
METHOD(aead_t, set_key, bool,
private_aead_t *this, chunk_t key)
{
chunk_t sig, enc;
chunk_split(key, "mm", this->signer->get_key_size(this->signer), &sig,
this->crypter->get_key_size(this->crypter), &enc);
return this->signer->set_key(this->signer, sig) &&
this->crypter->set_key(this->crypter, enc);
}
METHOD(aead_t, destroy, void,
private_aead_t *this)
{
this->iv_gen->destroy(this->iv_gen);
this->crypter->destroy(this->crypter);
this->signer->destroy(this->signer);
free(this);
}
/**
* See header
*/
aead_t *aead_create(crypter_t *crypter, signer_t *signer)
{
private_aead_t *this;
INIT(this,
.public = {
.encrypt = _encrypt,
.decrypt = _decrypt,
.get_block_size = _get_block_size,
.get_icv_size = _get_icv_size,
.get_iv_size = _get_iv_size,
.get_iv_gen = _get_iv_gen,
.get_key_size = _get_key_size,
.set_key = _set_key,
.destroy = _destroy,
},
.crypter = crypter,
.signer = signer,
.iv_gen = iv_gen_rand_create(),
);
return &this->public;
}
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