aes_edu/lib.rs
1//! A crate for applying the AES algorithms individual steps. The crate has not be verified by a security professional and may contain mistakes, use at your own risk. The crate is
2//! as such intended to be used for educational purposes.
3
4/// This module contains functions specific to the actual algorithm (Mix Columns, Shift Rows, etc)
5pub mod aesfunctions {
6
7 /// This struct represents a block to be used in the AES Cipher.
8 #[derive(Debug, Clone)]
9 pub struct Block {
10 /// An optional parameter that can be used for keeping track of blocks.
11 pub id: usize,
12 /// Represents the 16 byte (128 bit) state matrix used in the AES Cipher.
13 pub bytes: [u8; 16]
14 }
15
16 pub trait AES {
17 fn add_round_key(&mut self, key: &Vec<u8>);
18 fn mix_columns(&mut self);
19 fn shift_rows(&mut self);
20 fn sub_bytes(&mut self);
21 fn inv_mix_columns(&mut self);
22 fn inv_shift_rows(&mut self);
23 fn inv_sub_bytes(&mut self);
24 }
25
26 impl AES for Block {
27
28 /// This function performs the AES Ciphers Add Round Key operation on the [Block]s state matrix (4x4, 16 byte matrix).
29 ///
30 /// # Examples
31 ///
32 /// ```
33 /// use aes_functions::aesfunctions::{Block, AES};
34 ///
35 /// let mut block: Block = Block { id: 0, bytes: [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]};
36 /// let key: Vec<u8> = vec![0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF];
37 ///
38 /// //Apply Add Round Key Operation
39 /// block.add_round_key(&key);
40 ///
41 /// assert_eq!(block.bytes, [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF])
42 /// ```
43 fn add_round_key(&mut self, key: &Vec<u8>) {
44 for (a, b) in self.bytes.iter_mut().zip(key) {
45 *a = *a ^ b;
46 }
47 }
48
49 /// This function performs the AES Ciphers Substitute Bytes operation on the [Block]s state matrix (4x4, 16 byte matrix).
50 ///
51 /// # Examples
52 ///
53 /// ```
54 /// use aes_functions::aesfunctions::{Block, AES};
55 ///
56 /// let mut block: Block = Block { id: 0, bytes: [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]};
57 ///
58 /// //Apply Substitute Bytes Operation
59 /// block.sub_bytes();
60 ///
61 /// assert_eq!(block.bytes, [0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63])
62 /// ```
63 fn sub_bytes(&mut self) {
64 for byte in self.bytes.iter_mut() {
65 let nibble_a: usize = (*byte >> 4) as usize;
66 let nibble_b: usize = (*byte & 0x0f) as usize;
67 *byte = S_BOX[nibble_a][nibble_b];
68 }
69 }
70
71 /// This function performs the AES Ciphers Substitute Bytes operation on the [Block]s state matrix (4x4, 16 byte matrix).
72 ///
73 /// # Examples
74 ///
75 /// ```
76 /// use aes_functions::aesfunctions::{Block, AES};
77 ///
78 /// let mut block: Block = Block { id: 0, bytes: [0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63]};
79 ///
80 /// //Apply Inverse Substitute Bytes Operation
81 /// block.inv_sub_bytes();
82 ///
83 /// assert_eq!(block.bytes, [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00])
84 /// ```
85 fn inv_sub_bytes(&mut self) {
86 for byte in self.bytes.iter_mut() {
87 let nibble_a:usize = (*byte >> 4) as usize;
88 let nibble_b:usize = (*byte & 0x0f) as usize;
89 *byte = INV_S_BOX[nibble_a][nibble_b];
90 }
91 }
92
93 /// This function performs the AES Ciphers Shift Rows operation on the [Block]s state matrix (4x4, 16 byte matrix).
94 ///
95 /// # Examples
96 ///
97 /// ```
98 /// use aes_functions::aesfunctions::{Block, AES};
99 ///
100 /// let mut block: Block = Block { id: 0, bytes: [0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04]};
101 ///
102 /// //Apply Shift Rows Operation
103 /// block.shift_rows();
104 ///
105 /// assert_eq!(block.bytes, [0x01, 0x02, 0x03, 0x04, 0x02, 0x03, 0x04, 0x01, 0x03, 0x04, 0x01, 0x02, 0x04, 0x01, 0x02, 0x03])
106 /// ```
107 fn shift_rows(&mut self) {
108 let mut columns: Vec<Vec<u8>> = self.bytes.chunks(4).map(|x| x.to_owned()).collect();
109
110 let mut rows: Vec<Vec<u8>> = vec![columns.iter().map(|x| x[0]).collect(), columns.iter().map(|x| x[1]).collect(), columns.iter().map(|x| x[2]).collect(), columns.iter().map(|x| x[3]).collect()];
111
112 for (i, row) in rows.iter_mut().enumerate() {
113 row.rotate_left(i);
114 }
115
116 columns = vec![rows.iter().map(|x| x[0]).collect(), rows.iter().map(|x| x[1]).collect(), rows.iter().map(|x| x[2]).collect(), rows.iter().map(|x| x[3]).collect()];
117 self.bytes = columns.concat().try_into().unwrap();
118 }
119
120 /// This function performs the AES Ciphers Inverse Shift Rows operation on the [Block]s state matrix (4x4, 16 byte matrix).
121 ///
122 /// # Examples
123 ///
124 /// ```
125 /// use aes_functions::aesfunctions::{Block, AES};
126 ///
127 /// let mut block: Block = Block { id: 0, bytes: [0x01, 0x02, 0x03, 0x04, 0x02, 0x03, 0x04, 0x01, 0x03, 0x04, 0x01, 0x02, 0x04, 0x01, 0x02, 0x03]};
128 ///
129 /// //Apply Inverse Shift Rows Operation
130 /// block.inv_shift_rows();
131 ///
132 /// assert_eq!(block.bytes, [0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x02, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04, 0x04, 0x04])
133 /// ```
134 fn inv_shift_rows(&mut self) {
135 let mut columns: Vec<Vec<u8>> = self.bytes.chunks(4).map(|x| x.to_owned()).collect();
136
137 let mut rows: Vec<Vec<u8>> = vec![columns.iter().map(|x| x[0]).collect(), columns.iter().map(|x| x[1]).collect(), columns.iter().map(|x| x[2]).collect(), columns.iter().map(|x| x[3]).collect()];
138
139 for (i, row) in rows.iter_mut().enumerate() {
140 row.rotate_right(i);
141 }
142
143 columns = vec![rows.iter().map(|x| x[0]).collect(), rows.iter().map(|x| x[1]).collect(), rows.iter().map(|x| x[2]).collect(), rows.iter().map(|x| x[3]).collect()];
144 self.bytes = columns.concat().try_into().unwrap();
145 }
146
147 /// This function performs the AES Ciphers Mix Columns operation on the [Block]s state matrix (4x4, 16 byte matrix).
148 ///
149 /// # Examples
150 ///
151 /// ```
152 /// use aes_functions::aesfunctions::{Block, AES};
153 ///
154 /// let mut block: Block = Block { id: 0, bytes: [0xff, 0x65, 0xc7, 0xcc, 0xff, 0x65, 0xc7, 0xcc, 0xff, 0x65, 0xc7, 0xcc, 0xff, 0x65, 0xc7, 0xcc]};
155 ///
156 /// //Apply Inverse Mix Columns Operation
157 /// block.mix_columns();
158 ///
159 /// assert_eq!(block.bytes, [65, 171, 64, 59, 65, 171, 64, 59, 65, 171, 64, 59, 65, 171, 64, 59])
160 /// ```
161 fn mix_columns(&mut self) {
162 let mut split_data: Vec<Vec<u8>> = self.bytes.chunks(4).map(|x| x.to_owned()).collect();
163 let mut mixed_data: Vec<Vec<u8>> = vec![vec![0,0,0,0]; split_data.len()];
164 for (i, column) in split_data.iter_mut().enumerate() {
165
166 mixed_data[i][0] = g_mul(0x02, column[0]) ^ g_mul(0x03, column[1]) ^ g_mul(0x01, column[2]) ^ g_mul(0x01, column[3]);
167 mixed_data[i][1] = g_mul(0x01, column[0]) ^ g_mul(0x02, column[1]) ^ g_mul(0x03, column[2]) ^ g_mul(0x01, column[3]);
168 mixed_data[i][2] = g_mul(0x01, column[0]) ^ g_mul(0x01, column[1]) ^ g_mul(0x02, column[2]) ^ g_mul(0x03, column[3]);
169 mixed_data[i][3] = g_mul(0x03, column[0]) ^ g_mul(0x01, column[1]) ^ g_mul(0x01, column[2]) ^ g_mul(0x02, column[3]);
170 }
171
172 self.bytes = mixed_data.concat().try_into().unwrap();
173 }
174
175 /// This function performs the AES Ciphers Inverse Mix Columns operation on the [Block]s state matrix (4x4, 16 byte matrix).
176 ///
177 /// # Examples
178 ///
179 /// ```
180 /// use aes_functions::aesfunctions::{Block, AES};
181 ///
182 /// let mut block: Block = Block { id: 0, bytes: [0x41, 0xAB, 0x40, 0x3B, 0x41, 0xAB, 0x40, 0x3B, 0x41, 0xAB, 0x40, 0x3B, 0x41, 0xAB, 0x40, 0x3B]};
183 ///
184 /// //Apply Inverse Mix Columns Operation
185 /// block.inv_mix_columns();
186 ///
187 /// assert_eq!(block.bytes, [0xff, 0x65, 0xc7, 0xcc, 0xff, 0x65, 0xc7, 0xcc, 0xff, 0x65, 0xc7, 0xcc, 0xff, 0x65, 0xc7, 0xcc])
188 /// ```
189 fn inv_mix_columns(&mut self) {
190 let mut split_data: Vec<Vec<u8>> = self.bytes.chunks(4).map(|x| x.to_owned()).collect();
191 let mut mixed_data: Vec<Vec<u8>> = vec![vec![0,0,0,0]; split_data.len()];
192 for (i, column) in split_data.iter_mut().enumerate() {
193
194 mixed_data[i][0] = g_mul(0x0e, column[0]) ^ g_mul(0x0b, column[1]) ^ g_mul(0x0d, column[2]) ^ g_mul(0x09, column[3]);
195 mixed_data[i][1] = g_mul(0x09, column[0]) ^ g_mul(0x0e, column[1]) ^ g_mul(0x0b, column[2]) ^ g_mul(0x0d, column[3]);
196 mixed_data[i][2] = g_mul(0x0d, column[0]) ^ g_mul(0x09, column[1]) ^ g_mul(0x0e, column[2]) ^ g_mul(0x0b, column[3]);
197 mixed_data[i][3] = g_mul(0x0b, column[0]) ^ g_mul(0x0d, column[1]) ^ g_mul(0x09, column[2]) ^ g_mul(0x0e, column[3]);
198 }
199
200 self.bytes = mixed_data.concat().try_into().unwrap();
201 }
202
203 }
204
205 /// This function performs multiplication within Galois Field 256 between 2 bytes.
206 ///
207 /// # Examples
208 ///
209 /// ```
210 /// use aes_functions::aesfunctions::g_mul;
211 ///
212 /// let byte_a: u8 = 0x56;
213 /// let byte_b: u8 = 0xAF;
214 ///
215 /// assert_eq!(g_mul(byte_a, byte_b), 0xA9)
216 /// ```
217 pub fn g_mul(mut a: u8, mut b: u8) -> u8 {
218 let mut p: u8 = 0;
219
220 for _i in 0..8 {
221 if (b & 1) != 0 {
222 p ^= a;
223 }
224
225 let hi_bit_set: bool = (a & 0x80) != 0;
226 a <<= 1;
227 if hi_bit_set {
228 a ^= 0x1b;
229 }
230 b >>= 1;
231 }
232 p
233 }
234
235 /// The Substitution box for the AES Cipher.
236 ///
237 /// # Examples
238 ///
239 /// ```
240 /// use aes_functions::aesfunctions::S_BOX;
241 ///
242 /// let byte: u8 = 0x00;
243 ///
244 /// let substituted_byte: u8 = S_BOX[0][0];
245 ///
246 /// assert_eq!(substituted_byte, 0x63);
247 /// ```
248 ///
249 pub const S_BOX: [[u8; 16]; 16] = [
250 [0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76],
251 [0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0],
252 [0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15],
253 [0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75],
254 [0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84],
255 [0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf],
256 [0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8],
257 [0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2],
258 [0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73],
259 [0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb],
260 [0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79],
261 [0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08],
262 [0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a],
263 [0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e],
264 [0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf],
265 [0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16]];
266
267
268 /// The Inverse Substitution box for the AES Cipher.
269 ///
270 /// # Examples
271 ///
272 /// ```
273 /// use aes_functions::aesfunctions::INV_S_BOX;
274 ///
275 /// let substituted_byte: u8 = 0x63;
276 ///
277 /// let byte: u8 = INV_S_BOX[6][3];
278 ///
279 /// assert_eq!(byte, 0x00);
280 /// ```
281 ///
282 pub const INV_S_BOX: [[u8; 16]; 16] = [
283 [0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb],
284 [0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb],
285 [0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e],
286 [0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25],
287 [0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92],
288 [0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84],
289 [0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06],
290 [0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b],
291 [0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73],
292 [0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e],
293 [0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b],
294 [0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4],
295 [0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f],
296 [0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef],
297 [0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61],
298 [0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d]];
299
300}