Symmetric Blind Decryption with Perfect Secrecy

<div>General overview of <svg height="11.8435pt" id="M221" style="vertical-align:-2.86834pt" version="1.1" viewbox="-0.0498162 -8.97516 82.2285 11.8435" width="82.2285pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M449 477V596C410 641 345 676 257 676C144 676 61 607 61 501C61 405 122 350 264 291C353 255 392 219 392 158C392 102 339 62 254 62C186 62 98 100 50 205H32L45 70C94 9 173 -14 258 -14C328 -14 383 4 424 41C456 72 481 119 481 168C481 264 431 322 287 378C226 402 146 443 146 505C146 556 188 600 252 600C327 600 397 561 430 477H449Z" id="g202-30"></path></g><g transform="matrix(.013,0,0,-0.013,7.059,0)"><path d="M453 453H368L259 130L120 453H34L222 27C219 16 214 5 211 -6C187 -81 149 -144 105 -144C90 -144 72 -140 45 -120H28V-192C48 -211 76 -216 103 -216C192 -216 236 -155 275 -44L453 453Z" id="g202-62"></path></g><g transform="matrix(.013,0,0,-0.013,13.375,0)"><path d="M691 0V315C691 415 625 463 551 463C502 463 448 441 409 398C381 441 331 463 278 463C226 463 172 443 139 402V459L130 464L65 440V0H142V302C161 361 235 392 262 392C313 392 339 362 339 290V0H417V302C435 360 507 392 535 392C586 392 614 365 614 293V0H691Z" id="g202-50"></path></g><g transform="matrix(.013,0,0,-0.013,23.24,0)"><path d="M691 0V315C691 415 625 463 551 463C502 463 448 441 409 398C381 441 331 463 278 463C226 463 172 443 139 402V459L130 464L65 440V0H142V302C161 361 235 392 262 392C313 392 339 362 339 290V0H417V302C435 360 507 392 535 392C586 392 614 365 614 293V0H691Z" id="g202-50"></path></g><g transform="matrix(.013,0,0,-0.013,33.105,0)"><path d="M362 167C332 96 291 61 238 61C164 61 102 117 102 222H411V277C411 386 345 463 238 463C182 463 134 446 95 409C52 369 23 306 23 226C23 74 113 -10 230 -10C327 -10 380 34 428 132L362 167ZM115 293C128 364 183 392 230 392C274 392 327 378 330 293H115Z" id="g202-42"></path></g><g transform="matrix(.013,0,0,-0.013,38.898,0)"><path d="M287 87H275C251 64 231 61 211 61C180 61 160 75 160 137V382H264V453H160V580H142L81 517V453H46L1 399V382H81V104C81 35 119 -10 188 -10C221 -10 251 -7 276 12L287 87Z" id="g202-57"></path></g><g transform="matrix(.013,0,0,-0.013,42.696,0)"><path d="M328 377V447C309 462 287 463 271 463C231 463 179 446 144 395L142 459L133 464L63 440V0H142V234C165 333 212 392 269 392C276 392 301 388 308 377H328Z" id="g202-55"></path></g><g transform="matrix(.013,0,0,-0.013,47.08,0)"><path d="M156 586V679H64V586H156ZM152 0V459L143 464L69 440V0H152Z" id="g202-46"></path></g><g transform="matrix(.013,0,0,-0.013,49.951,0)"><path d="M367 166C332 90 283 61 238 61C164 61 102 121 102 222C102 334 166 392 238 392C280 392 327 376 351 317H367L411 371C378 435 313 463 242 463C118 463 23 363 23 216C23 132 58 69 107 30C143 2 183 -10 232 -10C272 -10 311 -1 347 24C380 47 409 81 432 132L367 166Z" id="g202-40"></path></g><g transform="matrix(.013,0,0,-0.013,55.901,0)"><path d="M74 662V0H314C362 0 406 9 441 26C505 59 547 124 547 193C547 273 510 337 419 366C483 395 511 443 511 499C511 611 434 662 279 662H74ZM161 394V588H291C383 588 422 562 422 499C422 427 370 394 251 394H161ZM161 74V317H240C308 317 350 315 385 304C430 289 458 250 458 202C458 131 410 74 287 74H161Z" id="g202-13"></path></g><g transform="matrix(.013,0,0,-0.013,63.782,0)"><path d="M144 0V679L135 684L61 660V0H144Z" id="g202-49"></path></g><g transform="matrix(.013,0,0,-0.013,66.457,0)"><path d="M156 586V679H64V586H156ZM152 0V459L143 464L69 440V0H152Z" id="g202-46"></path></g><g transform="matrix(.013,0,0,-0.013,69.328,0)"><path d="M424 0V321C424 362 415 394 397 418C374 441 330 463 290 463C235 463 191 453 139 402L137 459L128 464L63 440V0H142V302C163 361 230 392 263 392C314 392 345 369 345 304V0H424Z" id="g202-51"></path></g><g transform="matrix(.013,0,0,-0.013,75.683,0)"><path d="M437 13C433 46 431 95 431 128V679L422 684L352 660V426C316 453 280 463 245 463C125 463 28 351 28 209C28 121 70 48 126 13C153 -3 188 -10 217 -10C264 -10 317 8 354 44L356 -6L365 -11L437 13ZM352 158C329 98 284 61 237 61C210 61 186 68 163 85C128 112 107 166 107 222C107 325 180 392 249 392C288 392 325 369 352 329V158Z" id="g202-41"></path></g></svg>. Two tiers of encryption are applied. The outer tier (<svg height="9.10327pt" id="M222" style="vertical-align:-0.2324991pt" version="1.1" viewbox="-0.0498162 -8.87077 14.7664 9.10327" width="14.7664pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M449 477V596C410 641 345 676 257 676C144 676 61 607 61 501C61 405 122 350 264 291C353 255 392 219 392 158C392 102 339 62 254 62C186 62 98 100 50 205H32L45 70C94 9 173 -14 258 -14C328 -14 383 4 424 41C456 72 481 119 481 168C481 264 431 322 287 378C226 402 146 443 146 505C146 556 188 600 252 600C327 600 397 561 430 477H449Z" id="g202-30"></path></g><g transform="matrix(.013,0,0,-0.013,7.059,0)"><path d="M540 74H161V311H466V386H161V588H513V662H74V0H523L540 74Z" id="g202-16"></path></g></svg>) satisfies ordinary perfect secrecy. The inner tier (<svg height="8.92059pt" id="M223" style="vertical-align:-0.04981995pt" version="1.1" viewbox="-0.0498162 -8.87077 31.1948 8.92059" width="31.1948pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M469 71H177L337 270C420 375 446 411 446 491C446 591 368 676 249 676C145 676 58 595 37 476L109 459C122 558 186 605 242 605C318 605 367 559 367 475C367 420 327 374 266 302L210 234V235L35 21V0H440L469 71Z" id="g202-4"></path></g><g transform="matrix(.013,0,0,-0.013,6.524,0)"><path d="M74 662V0H161V285H281C428 285 512 363 512 478C512 597 433 662 258 662H74ZM161 359V588H244C375 588 424 551 424 479C424 400 376 359 249 359H161Z" id="g202-27"></path></g><g transform="matrix(.013,0,0,-0.013,13.375,0)"><path d="M635 0L346 674H320L31 0H127L208 200H457L539 0H635ZM427 274H239L333 503L427 274Z" id="g202-12"></path></g><g transform="matrix(.013,0,0,-0.013,22.065,0)"><path d="M74 662V0H289C536 0 656 156 656 327C656 539 528 662 240 662H74ZM161 74V588H221C332 588 407 577 471 532C542 484 567 420 567 328C567 229 533 155 454 114C387 79 326 74 210 74H161Z" id="g202-15"></path></g></svg>) provides perfect leak-freeness against Alice and has a transformation property enabling perfect blindness against the decryptor.</div>

Journal of Computer Networks and Communications

Symmetric Blind Decryption with Perfect Secrecy

Figure 6