This page contains lists of recent and most difficult challenges. To play the challenges, please go to the challenges section.

Category | Challenge | Points | Solves |

Crypto on the Web | JSON in JSON | 40 | 313 solves |

Block Ciphers | Oh SNAP | 120 | 60 solves |

Misc | L-Win | 120 | 50 solves |

Misc | Bruce Schneier's Password: Part 2 | 250 | 23 solves |

Misc | Bruce Schneier's Password | 100 | 81 solves |

Misc | Mixed Up | 120 | 61 solves |

Crypto on the Web | RSA or HMAC? | 35 | 431 solves |

Crypto on the Web | JWT Secrets | 25 | 566 solves |

Crypto on the Web | No Way JOSE | 20 | 617 solves |

Mathematics | Jack's Birthday Hash | 20 | 360 solves |

Mathematics | Jack's Birthday Confusion | 30 | 364 solves |

Crypto on the Web | Token Appreciation | 5 | 902 solves |

Crypto on the Web | JWT Sessions | 10 | 747 solves |

Mathematics | Cofactor Cofantasy | 150 | 108 solves |

Block Ciphers | Logon Zero | 80 | 144 solves |

RSA | RSA Backdoor Viability | 175 | 150 solves |

Misc | Jeff's LFSR | 150 | 55 solves |

General | Transparency | 50 | 1023 solves |

RSA | Let's Decrypt Again | 175 | 85 solves |

Misc | Twin Keys | 100 | 78 solves |

Misc | Invariant | 250 | 52 solves |

Misc | No Difference | 175 | 85 solves |

Misc | Trust Games | 150 | 67 solves |

Misc | PriMeD5 | 100 | 104 solves |

Mathematics | Ellipse Curve Cryptography | 125 | 133 solves |

RSA | Let's Decrypt | 80 | 171 solves |

Elliptic Curves | No Random, No Bias | 120 | 82 solves |

Elliptic Curves | Edwards Goes Degenerate | 100 | 90 solves |

Mathematics | Size and Basis | 15 | 1047 solves |

Mathematics | Gaussian Reduction | 50 | 623 solves |

Mathematics | Find the Lattice | 100 | 335 solves |

Mathematics | Vectors | 10 | 1091 solves |

Mathematics | Backpack Cryptography | 120 | 198 solves |

Mathematics | Gram Schmidt | 30 | 687 solves |

Mathematics | What's a Lattice? | 40 | 758 solves |

Mathematics | Unencryptable | 125 | 241 solves |

Misc | Too Many Errors | 100 | 110 solves |

Block Ciphers | Forbidden Fruit | 150 | 132 solves |

Misc | Collider | 50 | 333 solves |

Misc | MD0 | 80 | 189 solves |

Block Ciphers | Triple DES | 60 | 215 solves |

Mathematics | Modular Square Root | 35 | 1056 solves |

Mathematics | Broken RSA | 100 | 368 solves |

Mathematics | Real Eisenstein | 150 | 142 solves |

Block Ciphers | Keyed Permutations | 5 | 1875 solves |

Block Ciphers | Structure of AES | 15 | 1289 solves |

Block Ciphers | Round Keys | 20 | 1160 solves |

Block Ciphers | Resisting Bruteforce | 10 | 1708 solves |

Block Ciphers | Confusion through Substitution | 25 | 995 solves |

Block Ciphers | Bringing It All Together | 50 | 705 solves |

Category | Challenge | Points | Solves |

Misc | Bruce Schneier's Password: Part 2 | 250 | 23 solves |

Misc | L-Win | 120 | 50 solves |

Misc | Invariant | 250 | 52 solves |

Misc | Jeff's LFSR | 150 | 55 solves |

Block Ciphers | Oh SNAP | 120 | 60 solves |

Misc | Mixed Up | 120 | 61 solves |

Misc | Trust Games | 150 | 67 solves |

Misc | Twin Keys | 100 | 78 solves |

Misc | Bruce Schneier's Password | 100 | 81 solves |

Elliptic Curves | No Random, No Bias | 120 | 82 solves |

Misc | No Difference | 175 | 85 solves |

RSA | Let's Decrypt Again | 175 | 85 solves |

Elliptic Curves | Edwards Goes Degenerate | 100 | 90 solves |

Misc | PriMeD5 | 100 | 104 solves |

Mathematics | Cofactor Cofantasy | 150 | 108 solves |

Misc | Nothing Up My Sleeve | 150 | 109 solves |

Misc | Too Many Errors | 100 | 110 solves |

Block Ciphers | Forbidden Fruit | 150 | 132 solves |

Mathematics | Ellipse Curve Cryptography | 125 | 133 solves |

Misc | Toshi's Treasure | 150 | 138 solves |

Mathematics | Real Eisenstein | 150 | 142 solves |

Block Ciphers | Logon Zero | 80 | 144 solves |

Elliptic Curves | Moving Problems | 150 | 146 solves |

RSA | RSA Backdoor Viability | 175 | 150 solves |

Elliptic Curves | ProSign 3 | 100 | 155 solves |

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