| ... | ... | @@ -19,7 +19,6 @@ pub const State = struct { |
| 19 | 19 | pub const BLOCKBYTES = 48; |
| 20 | 20 | pub const RATE = 16; |
| 21 | 21 | |
| 22 | | // TODO: https://github.com/ziglang/zig/issues/2673#issuecomment-501763017 |
| 23 | 22 | data: [BLOCKBYTES / 4]u32, |
| 24 | 23 | |
| 25 | 24 | const Self = @This(); |
| ... | ... | @@ -134,6 +133,8 @@ pub const Hash = struct { |
| 134 | 133 | } |
| 135 | 134 | } |
| 136 | 135 | |
| 136 | pub const digest_length = 32; |
| 137 | |
| 137 | 138 | /// Finish the current hashing operation, writing the hash to `out` |
| 138 | 139 | /// |
| 139 | 140 | /// From 4.9 "Application to hashing" |
| ... | ... | @@ -166,3 +167,222 @@ test "hash" { |
| 166 | 167 | hash(&md, &msg); |
| 167 | 168 | htest.assertEqual("1C9A03DC6A5DDC5444CFC6F4B154CFF5CF081633B2CEA4D7D0AE7CCFED5AAA44", &md); |
| 168 | 169 | } |
| 170 | |
| 171 | pub const Aead = struct { |
| 172 | /// ad: Associated Data |
| 173 | /// npub: public nonce |
| 174 | /// k: private key |
| 175 | fn init(ad: []const u8, npub: [16]u8, k: [32]u8) State { |
| 176 | var state = State{ |
| 177 | .data = undefined, |
| 178 | }; |
| 179 | const buf = state.toSlice(); |
| 180 | |
| 181 | // Gimli-Cipher initializes a 48-byte Gimli state to a 16-byte nonce |
| 182 | // followed by a 32-byte key. |
| 183 | assert(npub.len + k.len == State.BLOCKBYTES); |
| 184 | std.mem.copy(u8, buf[0..npub.len], &npub); |
| 185 | std.mem.copy(u8, buf[npub.len .. npub.len + k.len], &k); |
| 186 | |
| 187 | // It then applies the Gimli permutation. |
| 188 | state.permute(); |
| 189 | |
| 190 | { |
| 191 | // Gimli-Cipher then handles each block of associated data, including |
| 192 | // exactly one final non-full block, in the same way as Gimli-Hash. |
| 193 | var data = ad; |
| 194 | while (data.len >= State.RATE) : (data = data[State.RATE..]) { |
| 195 | for (buf[0..State.RATE]) |*p, i| { |
| 196 | p.* ^= data[i]; |
| 197 | } |
| 198 | state.permute(); |
| 199 | } |
| 200 | for (buf[0..data.len]) |*p, i| { |
| 201 | p.* ^= data[i]; |
| 202 | } |
| 203 | |
| 204 | // XOR 1 into the next byte of the state |
| 205 | buf[data.len] ^= 1; |
| 206 | // XOR 1 into the last byte of the state, position 47. |
| 207 | buf[buf.len - 1] ^= 1; |
| 208 | |
| 209 | state.permute(); |
| 210 | } |
| 211 | |
| 212 | return state; |
| 213 | } |
| 214 | |
| 215 | /// c: ciphertext: output buffer should be of size m.len |
| 216 | /// at: authentication tag: output MAC |
| 217 | /// m: message |
| 218 | /// ad: Associated Data |
| 219 | /// npub: public nonce |
| 220 | /// k: private key |
| 221 | pub fn encrypt(c: []u8, at: *[State.RATE]u8, m: []const u8, ad: []const u8, npub: [16]u8, k: [32]u8) void { |
| 222 | assert(c.len == m.len); |
| 223 | |
| 224 | var state = Aead.init(ad, npub, k); |
| 225 | const buf = state.toSlice(); |
| 226 | |
| 227 | // Gimli-Cipher then handles each block of plaintext, including |
| 228 | // exactly one final non-full block, in the same way as Gimli-Hash. |
| 229 | // Whenever a plaintext byte is XORed into a state byte, the new state |
| 230 | // byte is output as ciphertext. |
| 231 | var in = m; |
| 232 | var out = c; |
| 233 | while (in.len >= State.RATE) : ({ |
| 234 | in = in[State.RATE..]; |
| 235 | out = out[State.RATE..]; |
| 236 | }) { |
| 237 | for (buf[0..State.RATE]) |*p, i| { |
| 238 | p.* ^= in[i]; |
| 239 | out[i] = p.*; |
| 240 | } |
| 241 | state.permute(); |
| 242 | } |
| 243 | for (buf[0..in.len]) |*p, i| { |
| 244 | p.* ^= in[i]; |
| 245 | out[i] = p.*; |
| 246 | } |
| 247 | |
| 248 | // XOR 1 into the next byte of the state |
| 249 | buf[in.len] ^= 1; |
| 250 | // XOR 1 into the last byte of the state, position 47. |
| 251 | buf[buf.len - 1] ^= 1; |
| 252 | |
| 253 | state.permute(); |
| 254 | |
| 255 | // After the final non-full block of plaintext, the first 16 bytes |
| 256 | // of the state are output as an authentication tag. |
| 257 | std.mem.copy(u8, at, buf[0..State.RATE]); |
| 258 | } |
| 259 | |
| 260 | /// m: message: output buffer should be of size c.len |
| 261 | /// c: ciphertext |
| 262 | /// at: authentication tag |
| 263 | /// ad: Associated Data |
| 264 | /// npub: public nonce |
| 265 | /// k: private key |
| 266 | /// NOTE: the check of the authentication tag is currently not done in constant time |
| 267 | pub fn decrypt(m: []u8, c: []const u8, at: [State.RATE]u8, ad: []u8, npub: [16]u8, k: [32]u8) !void { |
| 268 | assert(c.len == m.len); |
| 269 | |
| 270 | var state = Aead.init(ad, npub, k); |
| 271 | const buf = state.toSlice(); |
| 272 | |
| 273 | var in = c; |
| 274 | var out = m; |
| 275 | while (in.len >= State.RATE) : ({ |
| 276 | in = in[State.RATE..]; |
| 277 | out = out[State.RATE..]; |
| 278 | }) { |
| 279 | for (buf[0..State.RATE]) |*p, i| { |
| 280 | out[i] = p.* ^ in[i]; |
| 281 | p.* = in[i]; |
| 282 | } |
| 283 | state.permute(); |
| 284 | } |
| 285 | for (buf[0..in.len]) |*p, i| { |
| 286 | out[i] = p.* ^ in[i]; |
| 287 | p.* = in[i]; |
| 288 | } |
| 289 | |
| 290 | // XOR 1 into the next byte of the state |
| 291 | buf[in.len] ^= 1; |
| 292 | // XOR 1 into the last byte of the state, position 47. |
| 293 | buf[buf.len - 1] ^= 1; |
| 294 | |
| 295 | state.permute(); |
| 296 | |
| 297 | // After the final non-full block of plaintext, the first 16 bytes |
| 298 | // of the state are the authentication tag. |
| 299 | // TODO: use a constant-time equality check here, see https://github.com/ziglang/zig/issues/1776 |
| 300 | if (!mem.eql(u8, buf[0..State.RATE], &at)) { |
| 301 | @memset(m.ptr, undefined, m.len); |
| 302 | return error.InvalidMessage; |
| 303 | } |
| 304 | } |
| 305 | }; |
| 306 | |
| 307 | test "cipher" { |
| 308 | var key: [32]u8 = undefined; |
| 309 | try std.fmt.hexToBytes(&key, "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"); |
| 310 | var nonce: [16]u8 = undefined; |
| 311 | try std.fmt.hexToBytes(&nonce, "000102030405060708090A0B0C0D0E0F"); |
| 312 | { // test vector (1) from NIST KAT submission. |
| 313 | const ad: [0]u8 = undefined; |
| 314 | const pt: [0]u8 = undefined; |
| 315 | |
| 316 | var ct: [pt.len]u8 = undefined; |
| 317 | var at: [16]u8 = undefined; |
| 318 | Aead.encrypt(&ct, &at, &pt, &ad, nonce, key); |
| 319 | htest.assertEqual("", &ct); |
| 320 | htest.assertEqual("14DA9BB7120BF58B985A8E00FDEBA15B", &at); |
| 321 | |
| 322 | var pt2: [pt.len]u8 = undefined; |
| 323 | try Aead.decrypt(&pt2, &ct, at, &ad, nonce, key); |
| 324 | testing.expectEqualSlices(u8, &pt, &pt2); |
| 325 | } |
| 326 | { // test vector (34) from NIST KAT submission. |
| 327 | const ad: [0]u8 = undefined; |
| 328 | var pt: [2 / 2]u8 = undefined; |
| 329 | try std.fmt.hexToBytes(&pt, "00"); |
| 330 | |
| 331 | var ct: [pt.len]u8 = undefined; |
| 332 | var at: [16]u8 = undefined; |
| 333 | Aead.encrypt(&ct, &at, &pt, &ad, nonce, key); |
| 334 | htest.assertEqual("7F", &ct); |
| 335 | htest.assertEqual("80492C317B1CD58A1EDC3A0D3E9876FC", &at); |
| 336 | |
| 337 | var pt2: [pt.len]u8 = undefined; |
| 338 | try Aead.decrypt(&pt2, &ct, at, &ad, nonce, key); |
| 339 | testing.expectEqualSlices(u8, &pt, &pt2); |
| 340 | } |
| 341 | { // test vector (106) from NIST KAT submission. |
| 342 | var ad: [12 / 2]u8 = undefined; |
| 343 | try std.fmt.hexToBytes(&ad, "000102030405"); |
| 344 | var pt: [6 / 2]u8 = undefined; |
| 345 | try std.fmt.hexToBytes(&pt, "000102"); |
| 346 | |
| 347 | var ct: [pt.len]u8 = undefined; |
| 348 | var at: [16]u8 = undefined; |
| 349 | Aead.encrypt(&ct, &at, &pt, &ad, nonce, key); |
| 350 | htest.assertEqual("484D35", &ct); |
| 351 | htest.assertEqual("030BBEA23B61C00CED60A923BDCF9147", &at); |
| 352 | |
| 353 | var pt2: [pt.len]u8 = undefined; |
| 354 | try Aead.decrypt(&pt2, &ct, at, &ad, nonce, key); |
| 355 | testing.expectEqualSlices(u8, &pt, &pt2); |
| 356 | } |
| 357 | { // test vector (790) from NIST KAT submission. |
| 358 | var ad: [60 / 2]u8 = undefined; |
| 359 | try std.fmt.hexToBytes(&ad, "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D"); |
| 360 | var pt: [46 / 2]u8 = undefined; |
| 361 | try std.fmt.hexToBytes(&pt, "000102030405060708090A0B0C0D0E0F10111213141516"); |
| 362 | |
| 363 | var ct: [pt.len]u8 = undefined; |
| 364 | var at: [16]u8 = undefined; |
| 365 | Aead.encrypt(&ct, &at, &pt, &ad, nonce, key); |
| 366 | htest.assertEqual("6815B4A0ECDAD01596EAD87D9E690697475D234C6A13D1", &ct); |
| 367 | htest.assertEqual("DFE23F1642508290D68245279558B2FB", &at); |
| 368 | |
| 369 | var pt2: [pt.len]u8 = undefined; |
| 370 | try Aead.decrypt(&pt2, &ct, at, &ad, nonce, key); |
| 371 | testing.expectEqualSlices(u8, &pt, &pt2); |
| 372 | } |
| 373 | { // test vector (1057) from NIST KAT submission. |
| 374 | const ad: [0]u8 = undefined; |
| 375 | var pt: [64 / 2]u8 = undefined; |
| 376 | try std.fmt.hexToBytes(&pt, "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"); |
| 377 | |
| 378 | var ct: [pt.len]u8 = undefined; |
| 379 | var at: [16]u8 = undefined; |
| 380 | Aead.encrypt(&ct, &at, &pt, &ad, nonce, key); |
| 381 | htest.assertEqual("7F8A2CF4F52AA4D6B2E74105C30A2777B9D0C8AEFDD555DE35861BD3011F652F", &ct); |
| 382 | htest.assertEqual("7256456FA935AC34BBF55AE135F33257", &at); |
| 383 | |
| 384 | var pt2: [pt.len]u8 = undefined; |
| 385 | try Aead.decrypt(&pt2, &ct, at, &ad, nonce, key); |
| 386 | testing.expectEqualSlices(u8, &pt, &pt2); |
| 387 | } |
| 388 | } |