Basic kryptering
Tekst:
Krypteret tekst:
413 389 756 662 488 922 402 563 311 225 775 931 702 329 360 972 953 432 814 245 540 233 969
De-Krypteret tekst:
Brug af one-time-keypad
One-time pad
In cryptography, the one-time pad (OTP) is an encryption technique that cannot be cracked, but requires the use of a single-use pre-shared key that is larger than or equal to the size of the message being sent. In this technique, a plaintext is paired with a random secret key (also referred to as a one-time pad). Then, each bit or character of the plaintext is encrypted by combining it with the corresponding bit or character from the pad using modular addition. The resulting ciphertext will be impossible to decrypt or break if the following four conditions are met
- The key must be at least as long as the plaintext.
- The key must be truly random.
- The key must never be reused in whole or in part.
- The key must be kept completely secret by the communicating parties.
It has also been mathematically proven that any cipher with the property of perfect secrecy must use keys with effectively the same requirements as OTP keys. Digital versions of one-time pad ciphers have been used by nations for critical diplomatic and military communication, but the problems of secure key distribution make them impractical for most applications.
One-time-use-key-pad. Max 500 tegn
347 275 639 559 456 825 300 531 200 115 674 886 586 224 251 871 908 325 713 124 428 136 869 143 245 92 19 388 184 435 852 15 532 868 679 258 11 419 983 774 944 877 478 551 179 569 143 100 369 5 51 29 934 502 495 821 425 800 751 338 427 397 301 72 188 150 488 865 264 638 270 575 285 196 455 772 193 917 911 669 467 774 364 166 482 774 753 558 568 389 621 561 532 210 246 470 840 352 773 190 641 572 460 934 115 640 932 523 846 324 718 52 328 252 634 3 704 833 688 336 863 30 457 729 201 743 430 685 881 40 228 827 658 40 32 351 256 470 596 582 49 908 642 776 156 209 821 664 902 708 565 800 735 847 717 540 618 312 89 609 5 233 409 757 699 223 55 365 992 340 483 646 680 913 368 336 150 863 202 711 109 393 442 336 412 756 4 950 161 559 954 664 703 7 101 543 66 432 298 443 670 630 526 930 349 976 95 891 170 109 231 74 678 576 202 600 203 481 832 881 935 525 326 178 204 779 150 587 892 0 371 131 86 421 347 681 977 240 861 659 356 650 293 45 66 503 119 462 683 631 347 251 793 614 770 548 378 580 911 574 388 401 743 406 674 905 839 869 817 890 206 642 696 704 21 633 878 118 817 401 903 503 578 82 607 605 66 286 704 656 719 222 260 425 75 454 49 468 449 111 978 944 692 352 650 454 75 9 989 14 946 388 998 5 61 11 408 179 301 998 206 690 297 317 370 740 637 713 63 983 120 33 833 193 992 801 751 327 232 962 99 799 901 838 298 937 953 417 203 309 487 274 887 355 379 947 290 121 73 370 864 998 973 853 647 578 942 480 295 893 66 579 531 46 758 295 286 255 397 505 152 884 30 976 375 829 426 82 913 891 27 503 251 598 690 804 975 528 832 846 904 251 290 765 532 137 811 446 111 826 622 875 395 173 878 678 217 989 341 516 655 821 696 357 504 593 113 336 394 296 824 580 470 392 655 412 293 793 748 415 360 240 88 639 884 642 627 812 975 828 698 141 138 692 816 646 888 213 977 851 872 924 603 952 91 932 737 889 693 263 930 862 532 964 772 371 224 43 344 981 794 226 564 150 532 701 697 643 704 939 768 599 500 551 878 25 88 606 355 801
I kode er det relativt nemt at lave operationerne. Det er også nemt at udvide til 500+ tegn
Det store problem er udveksling af keys og at holde dem hemmelige