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 | 169 solves |
| Block Ciphers | Oh SNAP | 120 | 49 solves |
| Misc | L-Win | 120 | 41 solves |
| Misc | Bruce Schneier's Password: Part 2 | 250 | 19 solves |
| Misc | Bruce Schneier's Password | 100 | 65 solves |
| Misc | Mixed Up | 120 | 48 solves |
| Crypto on the Web | RSA or HMAC? | 35 | 305 solves |
| Crypto on the Web | JWT Secrets | 25 | 387 solves |
| Crypto on the Web | No Way JOSE | 20 | 418 solves |
| Mathematics | Jack's Birthday Hash | 20 | 258 solves |
| Mathematics | Jack's Birthday Confusion | 30 | 270 solves |
| Crypto on the Web | Token Appreciation | 5 | 612 solves |
| Crypto on the Web | JWT Sessions | 10 | 503 solves |
| Mathematics | Cofactor Cofantasy | 150 | 83 solves |
| Block Ciphers | Logon Zero | 80 | 116 solves |
| RSA | RSA Backdoor Viability | 175 | 113 solves |
| Misc | Jeff's LFSR | 150 | 51 solves |
| General | Transparency | 50 | 743 solves |
| RSA | Let's Decrypt Again | 175 | 75 solves |
| Misc | Twin Keys | 100 | 72 solves |
| Misc | Invariant | 250 | 48 solves |
| Misc | No Difference | 175 | 74 solves |
| Misc | Trust Games | 150 | 62 solves |
| Misc | PriMeD5 | 100 | 91 solves |
| Mathematics | Ellipse Curve Cryptography | 125 | 111 solves |
| RSA | Let's Decrypt | 80 | 142 solves |
| Elliptic Curves | No Random, No Bias | 120 | 71 solves |
| Elliptic Curves | Edwards Goes Degenerate | 100 | 75 solves |
| Mathematics | Size and Basis | 15 | 877 solves |
| Mathematics | Gaussian Reduction | 50 | 521 solves |
| Mathematics | Find the Lattice | 100 | 283 solves |
| Mathematics | Vectors | 10 | 917 solves |
| Mathematics | Backpack Cryptography | 120 | 176 solves |
| Mathematics | Gram Schmidt | 30 | 577 solves |
| Mathematics | What's a Lattice? | 40 | 632 solves |
| Mathematics | Unencryptable | 125 | 204 solves |
| Misc | Too Many Errors | 100 | 98 solves |
| Block Ciphers | Forbidden Fruit | 150 | 119 solves |
| Misc | Collider | 50 | 288 solves |
| Misc | MD0 | 80 | 160 solves |
| Block Ciphers | Triple DES | 60 | 184 solves |
| Mathematics | Modular Square Root | 35 | 906 solves |
| Mathematics | Broken RSA | 100 | 321 solves |
| Mathematics | Real Eisenstein | 150 | 129 solves |
| Block Ciphers | Keyed Permutations | 5 | 1500 solves |
| Block Ciphers | Structure of AES | 15 | 1045 solves |
| Block Ciphers | Round Keys | 20 | 948 solves |
| Block Ciphers | Resisting Bruteforce | 10 | 1377 solves |
| Block Ciphers | Confusion through Substitution | 25 | 813 solves |
| Block Ciphers | Bringing It All Together | 50 | 577 solves |
Least Solved
| Category | Challenge | Points | Solves |
| Misc | Bruce Schneier's Password: Part 2 | 250 | 19 solves |
| Misc | L-Win | 120 | 41 solves |
| Misc | Mixed Up | 120 | 48 solves |
| Misc | Invariant | 250 | 48 solves |
| Block Ciphers | Oh SNAP | 120 | 49 solves |
| Misc | Jeff's LFSR | 150 | 51 solves |
| Misc | Trust Games | 150 | 62 solves |
| Misc | Bruce Schneier's Password | 100 | 65 solves |
| Elliptic Curves | No Random, No Bias | 120 | 71 solves |
| Misc | Twin Keys | 100 | 72 solves |
| Misc | No Difference | 175 | 74 solves |
| Elliptic Curves | Edwards Goes Degenerate | 100 | 75 solves |
| RSA | Let's Decrypt Again | 175 | 75 solves |
| Mathematics | Cofactor Cofantasy | 150 | 83 solves |
| Misc | PriMeD5 | 100 | 91 solves |
| Misc | Too Many Errors | 100 | 98 solves |
| Misc | Nothing Up My Sleeve | 150 | 101 solves |
| Mathematics | Ellipse Curve Cryptography | 125 | 111 solves |
| RSA | RSA Backdoor Viability | 175 | 113 solves |
| Block Ciphers | Logon Zero | 80 | 116 solves |
| Block Ciphers | Forbidden Fruit | 150 | 119 solves |
| Elliptic Curves | Moving Problems | 150 | 128 solves |
| Mathematics | Real Eisenstein | 150 | 129 solves |
| Misc | Toshi's Treasure | 150 | 130 solves |
| Elliptic Curves | ProSign 3 | 100 | 140 solves |