1/**************************************************************************/
2/* aes_context.cpp */
3/**************************************************************************/
4/* This file is part of: */
5/* GODOT ENGINE */
6/* https://godotengine.org */
7/**************************************************************************/
8/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
9/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
10/* */
11/* Permission is hereby granted, free of charge, to any person obtaining */
12/* a copy of this software and associated documentation files (the */
13/* "Software"), to deal in the Software without restriction, including */
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16/* permit persons to whom the Software is furnished to do so, subject to */
17/* the following conditions: */
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20/* included in all copies or substantial portions of the Software. */
21/* */
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28/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
29/**************************************************************************/
30
31#include "core/crypto/aes_context.h"
32
33Error AESContext::start(Mode p_mode, PackedByteArray p_key, PackedByteArray p_iv) {
34 ERR_FAIL_COND_V_MSG(mode != MODE_MAX, ERR_ALREADY_IN_USE, "AESContext already started. Call 'finish' before starting a new one.");
35 ERR_FAIL_COND_V_MSG(p_mode < 0 || p_mode >= MODE_MAX, ERR_INVALID_PARAMETER, "Invalid mode requested.");
36 // Key check.
37 int key_bits = p_key.size() << 3;
38 ERR_FAIL_COND_V_MSG(key_bits != 128 && key_bits != 256, ERR_INVALID_PARAMETER, "AES key must be either 16 or 32 bytes");
39 // Initialization vector.
40 if (p_mode == MODE_CBC_ENCRYPT || p_mode == MODE_CBC_DECRYPT) {
41 ERR_FAIL_COND_V_MSG(p_iv.size() != 16, ERR_INVALID_PARAMETER, "The initialization vector (IV) must be exactly 16 bytes.");
42 iv.resize(0);
43 iv.append_array(p_iv);
44 }
45 // Encryption/decryption key.
46 if (p_mode == MODE_CBC_ENCRYPT || p_mode == MODE_ECB_ENCRYPT) {
47 ctx.set_encode_key(p_key.ptr(), key_bits);
48 } else {
49 ctx.set_decode_key(p_key.ptr(), key_bits);
50 }
51 mode = p_mode;
52 return OK;
53}
54
55PackedByteArray AESContext::update(PackedByteArray p_src) {
56 ERR_FAIL_COND_V_MSG(mode < 0 || mode >= MODE_MAX, PackedByteArray(), "AESContext not started. Call 'start' before calling 'update'.");
57 int len = p_src.size();
58 ERR_FAIL_COND_V_MSG(len % 16, PackedByteArray(), "The number of bytes to be encrypted must be multiple of 16. Add padding if needed");
59 PackedByteArray out;
60 out.resize(len);
61 const uint8_t *src_ptr = p_src.ptr();
62 uint8_t *out_ptr = out.ptrw();
63 switch (mode) {
64 case MODE_ECB_ENCRYPT: {
65 for (int i = 0; i < len; i += 16) {
66 Error err = ctx.encrypt_ecb(src_ptr + i, out_ptr + i);
67 ERR_FAIL_COND_V(err != OK, PackedByteArray());
68 }
69 } break;
70 case MODE_ECB_DECRYPT: {
71 for (int i = 0; i < len; i += 16) {
72 Error err = ctx.decrypt_ecb(src_ptr + i, out_ptr + i);
73 ERR_FAIL_COND_V(err != OK, PackedByteArray());
74 }
75 } break;
76 case MODE_CBC_ENCRYPT: {
77 Error err = ctx.encrypt_cbc(len, iv.ptrw(), p_src.ptr(), out.ptrw());
78 ERR_FAIL_COND_V(err != OK, PackedByteArray());
79 } break;
80 case MODE_CBC_DECRYPT: {
81 Error err = ctx.decrypt_cbc(len, iv.ptrw(), p_src.ptr(), out.ptrw());
82 ERR_FAIL_COND_V(err != OK, PackedByteArray());
83 } break;
84 default:
85 ERR_FAIL_V_MSG(PackedByteArray(), "Bug!");
86 }
87 return out;
88}
89
90PackedByteArray AESContext::get_iv_state() {
91 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.");
92 PackedByteArray out;
93 out.append_array(iv);
94 return out;
95}
96
97void AESContext::finish() {
98 mode = MODE_MAX;
99 iv.resize(0);
100}
101
102void AESContext::_bind_methods() {
103 ClassDB::bind_method(D_METHOD("start", "mode", "key", "iv"), &AESContext::start, DEFVAL(PackedByteArray()));
104 ClassDB::bind_method(D_METHOD("update", "src"), &AESContext::update);
105 ClassDB::bind_method(D_METHOD("get_iv_state"), &AESContext::get_iv_state);
106 ClassDB::bind_method(D_METHOD("finish"), &AESContext::finish);
107 BIND_ENUM_CONSTANT(MODE_ECB_ENCRYPT);
108 BIND_ENUM_CONSTANT(MODE_ECB_DECRYPT);
109 BIND_ENUM_CONSTANT(MODE_CBC_ENCRYPT);
110 BIND_ENUM_CONSTANT(MODE_CBC_DECRYPT);
111 BIND_ENUM_CONSTANT(MODE_MAX);
112}
113
114AESContext::AESContext() {
115}
116