98 Proving that a Russian cryptographic standard is too structured 2019-06-07T05:14:03.617

81 Print a Tabula Recta! 2016-07-30T15:53:42.530

44 The Drunken Bishop 2015-10-04T22:11:31.997

35 ROT-13 transform standard input 2011-01-27T21:11:06.677

34 Cryptographic hash golf 2015-05-31T14:44:50.913

33 Underhanded Password Hashing 2012-03-28T22:22:06.583

28 Decipher Neurotic Frogs 2016-09-10T23:03:56.310

27 Atbash Self Palindromes 2016-01-07T03:59:22.210

25 What ROT is this? - decrypt ROT-n 2014-03-23T02:32:22.860

25 PKCS#7 padding validation 2016-08-27T15:20:07.520

25 Gimli, make it even shorter? 2017-09-08T22:29:41.697

23 Implement ROT-47... in ROT-47 2014-03-03T20:46:47.133

22 Cryptographic quine variant 2012-11-09T12:08:52.913

20 Write a Playfair encryption program 2014-03-07T00:55:09.380

18 Write a VIC cipher encoder 2016-08-07T06:03:49.603

17 Write Buggy Code 2011-04-26T05:31:38.857

17 C: replace AES FIPS-197 SubBytes table by constant-time code 2012-12-21T17:40:24.530

17 A fiercer four-square cipher 2015-07-31T20:05:07.990

17 Shamir's Secret Sharing 2016-07-07T15:34:44.333

16 Convert ciphered Roman numerals to Arabic decimals 2015-10-14T07:46:58.917

15 Implement Rijndael's S-box 2011-10-04T02:26:29.103

15 Shifty XORyption 2015-04-25T16:55:24.837

15 Generate a cipher 2016-11-22T14:26:07.463

14 Bacon's cipher: An Intro to Steganography 2015-12-08T11:50:46.200

13 Implement a One-Time Pad 2012-03-16T20:21:31.393

13 Shifting Caesars Shifts 2017-07-18T16:22:36.543

12 Break the broken cipher 2011-02-27T20:37:18.973

12 Cryptographic hash golf (robbers) 2015-05-31T14:45:51.143

12 Cryptic Kicker // 2015-08-08T10:12:18.100

11 Decryption by pattern analysis 2011-01-30T23:58:29.030

11 Implement Shamir's Secret Sharing reconstruction 2011-03-01T02:21:51.677

11 Solve a Diagonal Burrows-Wheeler transform 2015-02-27T02:28:50.097

11 CipherSaber encryption 2015-07-26T04:50:43.243

11 Decode the hidden message! 2017-04-05T21:04:47.497

11 Russian Caesar cipher 2019-10-10T06:57:39.030

10 Rail fence cipher 2013-01-25T09:48:56.540

10 Decrypting a block of AES 2015-03-21T18:36:53.527

8 Time for some TEA! 2016-06-24T18:46:16.083

8 Generate an RSA key pair 2018-11-06T01:23:44.853

7 2nd byte bias of RC4 2014-07-31T18:15:24.303

7 Crack a Vigenère Cipher 2015-09-29T22:55:37.617

7 An Affinity for Ciphers 2015-10-13T02:41:06.157

6 Break the broken hash 2011-03-07T01:34:24.393

6 Key length of Vigenère cipher 2015-02-13T11:26:04.587

6 ADFGX Cipher Encryption 2016-02-13T15:22:52.980

6 Help the poor Cryptographers - DLP Edition 2016-07-22T19:58:01.323

6 Write a VIC cipher decoder 2016-08-07T06:04:53.730

5 Implement Oplop 2012-02-28T00:11:04.180

5 Out Steganograph Me! 2016-11-14T01:57:24.997

4 Implement DES key expansion 2012-11-14T21:05:16.757

4 Compress and Decompress sentence using vowel based encryption cipher 2014-08-04T06:34:46.997

4 Straddling Checkerboard Cipher 2017-05-30T18:21:37.317

3 Build an RSA encoder 2013-02-15T17:21:34.150

2 Solve a Date Shift Cipher 2015-02-28T05:55:05.493

2 Crack the Cipher 2016-03-17T20:21:29.657

2 Shh... Can You Split a Secret? 2017-03-23T21:41:20.640

0 Golf: Tabula Recta 2015-08-22T17:46:24.283

-2 Convert alphanumeric (base-36) sentences into hexadecimal (base-16) sentences 2019-05-25T00:46:20.053

-5 Implement the MD5 algorithm! 2017-06-11T20:20:00.990

-7 Substitution cipher 2016-04-15T22:56:52.023

-8 Challenge: Crack the code 2014-09-10T21:24:36.010