New Challenges
This page contains lists of recent and most difficult challenges. To play the challenges, please go to the challenges section.
Recently Released
| Category | Challenge | Points | Solves |
| Crypto on the Web | JSON in JSON | 40 | 417 solves |
| Block Ciphers | Oh SNAP | 120 | 82 solves |
| Misc | L-Win | 120 | 68 solves |
| Misc | Bruce Schneier's Password: Part 2 | 250 | 33 solves |
| Misc | Bruce Schneier's Password | 100 | 101 solves |
| Misc | Mixed Up | 120 | 80 solves |
| Crypto on the Web | RSA or HMAC? | 35 | 519 solves |
| Crypto on the Web | JWT Secrets | 25 | 680 solves |
| Crypto on the Web | No Way JOSE | 20 | 739 solves |
| Mathematics | Jack's Birthday Hash | 20 | 461 solves |
| Mathematics | Jack's Birthday Confusion | 30 | 462 solves |
| Crypto on the Web | Token Appreciation | 5 | 1128 solves |
| Crypto on the Web | JWT Sessions | 10 | 921 solves |
| Mathematics | Cofactor Cofantasy | 150 | 132 solves |
| Block Ciphers | Logon Zero | 80 | 169 solves |
| RSA | RSA Backdoor Viability | 175 | 201 solves |
| Misc | Jeff's LFSR | 150 | 72 solves |
| General | Transparency | 50 | 1227 solves |
| RSA | Let's Decrypt Again | 175 | 96 solves |
| Misc | Twin Keys | 100 | 93 solves |
| Misc | Invariant | 250 | 59 solves |
| Misc | No Difference | 175 | 97 solves |
| Misc | Trust Games | 150 | 78 solves |
| Misc | PriMeD5 | 100 | 119 solves |
| Mathematics | Ellipse Curve Cryptography | 125 | 162 solves |
| RSA | Let's Decrypt | 80 | 195 solves |
| Elliptic Curves | No Random, No Bias | 120 | 99 solves |
| Elliptic Curves | Edwards Goes Degenerate | 100 | 101 solves |
| Mathematics | Size and Basis | 15 | 1227 solves |
| Mathematics | Gaussian Reduction | 50 | 727 solves |
| Mathematics | Find the Lattice | 100 | 386 solves |
| Mathematics | Vectors | 10 | 1271 solves |
| Mathematics | Backpack Cryptography | 120 | 235 solves |
| Mathematics | Gram Schmidt | 30 | 806 solves |
| Mathematics | What's a Lattice? | 40 | 886 solves |
| Mathematics | Unencryptable | 125 | 285 solves |
| Misc | Too Many Errors | 100 | 118 solves |
| Block Ciphers | Forbidden Fruit | 150 | 153 solves |
| Misc | Collider | 50 | 383 solves |
| Misc | MD0 | 80 | 218 solves |
| Block Ciphers | Triple DES | 60 | 259 solves |
| Mathematics | Modular Square Root | 35 | 1208 solves |
| Mathematics | Broken RSA | 100 | 412 solves |
| Mathematics | Real Eisenstein | 150 | 169 solves |
| Block Ciphers | Keyed Permutations | 5 | 2166 solves |
| Block Ciphers | Structure of AES | 15 | 1462 solves |
| Block Ciphers | Round Keys | 20 | 1311 solves |
| Block Ciphers | Resisting Bruteforce | 10 | 1974 solves |
| Block Ciphers | Confusion through Substitution | 25 | 1131 solves |
| Block Ciphers | Bringing It All Together | 50 | 797 solves |
Least Solved
| Category | Challenge | Points | Solves |
| Misc | Bruce Schneier's Password: Part 2 | 250 | 33 solves |
| Misc | Invariant | 250 | 59 solves |
| Misc | L-Win | 120 | 68 solves |
| Misc | Jeff's LFSR | 150 | 72 solves |
| Misc | Trust Games | 150 | 78 solves |
| Misc | Mixed Up | 120 | 80 solves |
| Block Ciphers | Oh SNAP | 120 | 82 solves |
| Misc | Twin Keys | 100 | 93 solves |
| RSA | Let's Decrypt Again | 175 | 96 solves |
| Misc | No Difference | 175 | 97 solves |
| Elliptic Curves | No Random, No Bias | 120 | 99 solves |
| Elliptic Curves | Edwards Goes Degenerate | 100 | 101 solves |
| Misc | Bruce Schneier's Password | 100 | 101 solves |
| Misc | Too Many Errors | 100 | 118 solves |
| Misc | PriMeD5 | 100 | 119 solves |
| Misc | Nothing Up My Sleeve | 150 | 120 solves |
| Mathematics | Cofactor Cofantasy | 150 | 132 solves |
| Misc | Toshi's Treasure | 150 | 149 solves |
| Block Ciphers | Forbidden Fruit | 150 | 153 solves |
| Mathematics | Ellipse Curve Cryptography | 125 | 162 solves |
| Misc | Bit by Bit | 100 | 168 solves |
| Elliptic Curves | Moving Problems | 150 | 168 solves |
| Mathematics | Real Eisenstein | 150 | 169 solves |
| Block Ciphers | Logon Zero | 80 | 169 solves |
| Elliptic Curves | ProSign 3 | 100 | 176 solves |