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/**************************************************************************/
/* aes_context.cpp */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/**************************************************************************/
#include "core/crypto/aes_context.h"
Error AESContext::start(Mode p_mode, PackedByteArray p_key, PackedByteArray p_iv) {
ERR_FAIL_COND_V_MSG(mode != MODE_MAX, ERR_ALREADY_IN_USE, "AESContext already started. Call 'finish' before starting a new one.");
ERR_FAIL_COND_V_MSG(p_mode < 0 || p_mode >= MODE_MAX, ERR_INVALID_PARAMETER, "Invalid mode requested.");
// Key check.
int key_bits = p_key.size() << 3;
ERR_FAIL_COND_V_MSG(key_bits != 128 && key_bits != 256, ERR_INVALID_PARAMETER, "AES key must be either 16 or 32 bytes");
// Initialization vector.
if (p_mode == MODE_CBC_ENCRYPT || p_mode == MODE_CBC_DECRYPT) {
ERR_FAIL_COND_V_MSG(p_iv.size() != 16, ERR_INVALID_PARAMETER, "The initialization vector (IV) must be exactly 16 bytes.");
iv.resize(0);
iv.append_array(p_iv);
}
// Encryption/decryption key.
if (p_mode == MODE_CBC_ENCRYPT || p_mode == MODE_ECB_ENCRYPT) {
ctx.set_encode_key(p_key.ptr(), key_bits);
} else {
ctx.set_decode_key(p_key.ptr(), key_bits);
}
mode = p_mode;
return OK;
}
PackedByteArray AESContext::update(PackedByteArray p_src) {
ERR_FAIL_COND_V_MSG(mode < 0 || mode >= MODE_MAX, PackedByteArray(), "AESContext not started. Call 'start' before calling 'update'.");
int len = p_src.size();
ERR_FAIL_COND_V_MSG(len % 16, PackedByteArray(), "The number of bytes to be encrypted must be multiple of 16. Add padding if needed");
PackedByteArray out;
out.resize(len);
const uint8_t *src_ptr = p_src.ptr();
uint8_t *out_ptr = out.ptrw();
switch (mode) {
case MODE_ECB_ENCRYPT: {
for (int i = 0; i < len; i += 16) {
Error err = ctx.encrypt_ecb(src_ptr + i, out_ptr + i);
ERR_FAIL_COND_V(err != OK, PackedByteArray());
}
} break;
case MODE_ECB_DECRYPT: {
for (int i = 0; i < len; i += 16) {
Error err = ctx.decrypt_ecb(src_ptr + i, out_ptr + i);
ERR_FAIL_COND_V(err != OK, PackedByteArray());
}
} break;
case MODE_CBC_ENCRYPT: {
Error err = ctx.encrypt_cbc(len, iv.ptrw(), p_src.ptr(), out.ptrw());
ERR_FAIL_COND_V(err != OK, PackedByteArray());
} break;
case MODE_CBC_DECRYPT: {
Error err = ctx.decrypt_cbc(len, iv.ptrw(), p_src.ptr(), out.ptrw());
ERR_FAIL_COND_V(err != OK, PackedByteArray());
} break;
default:
ERR_FAIL_V_MSG(PackedByteArray(), "Bug!");
}
return out;
}
PackedByteArray AESContext::get_iv_state() {
ERR_FAIL_COND_V_MSG(mode != MODE_CBC_ENCRYPT && mode != MODE_CBC_DECRYPT, PackedByteArray(), "Calling 'get_iv_state' only makes sense when the context is started in CBC mode.");
PackedByteArray out;
out.append_array(iv);
return out;
}
void AESContext::finish() {
mode = MODE_MAX;
iv.resize(0);
}
void AESContext::_bind_methods() {
ClassDB::bind_method(D_METHOD("start", "mode", "key", "iv"), &AESContext::start, DEFVAL(PackedByteArray()));
ClassDB::bind_method(D_METHOD("update", "src"), &AESContext::update);
ClassDB::bind_method(D_METHOD("get_iv_state"), &AESContext::get_iv_state);
ClassDB::bind_method(D_METHOD("finish"), &AESContext::finish);
BIND_ENUM_CONSTANT(MODE_ECB_ENCRYPT);
BIND_ENUM_CONSTANT(MODE_ECB_DECRYPT);
BIND_ENUM_CONSTANT(MODE_CBC_ENCRYPT);
BIND_ENUM_CONSTANT(MODE_CBC_DECRYPT);
BIND_ENUM_CONSTANT(MODE_MAX);
}
AESContext::AESContext() {
}
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