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 |
| Mathematics | No Way Back Home | 100 | 86 solves |
| Symmetric Ciphers | Beatboxer | 150 | 43 solves |
| Hash Functions | MDFlag | 125 | 43 solves |
| Crypto on the Web | TLS Handshake | 15 | 95 solves |
| Crypto on the Web | Saying Hello | 20 | 92 solves |
| Crypto on the Web | Secure Protocols | 5 | 111 solves |
| Crypto on the Web | Sharks on the Wire | 10 | 100 solves |
| Elliptic Curves | Real Curve Crypto | 200 | 26 solves |
| Crypto on the Web | RSA or HMAC? Part 2 | 100 | 308 solves |
| Mathematics | Roll your Own | 125 | 173 solves |
| Symmetric Ciphers | Dancing Queen | 120 | 201 solves |
| General | SSH Keys | 35 | 1570 solves |
| Misc | LFSR Destroyer | 250 | 56 solves |
| Hash Functions | Hash Stuffing | 50 | 303 solves |
| Elliptic Curves | Montgomery's Ladder | 40 | 313 solves |
| Elliptic Curves | Double and Broken | 50 | 171 solves |
| Diffie-Hellman | The Matrix Revolutions | 125 | 120 solves |
| Diffie-Hellman | The Matrix Reloaded | 100 | 189 solves |
| Diffie-Hellman | The Matrix | 75 | 256 solves |
| Crypto on the Web | JSON in JSON | 40 | 867 solves |
| Symmetric Ciphers | Oh SNAP | 120 | 199 solves |
| Misc | L-Win | 120 | 165 solves |
| Misc | Bruce Schneier's Password: Part 2 | 250 | 78 solves |
| Misc | Bruce Schneier's Password | 100 | 227 solves |
| Hash Functions | Mixed Up | 120 | 205 solves |
| Crypto on the Web | RSA or HMAC? | 35 | 960 solves |
| Crypto on the Web | JWT Secrets | 25 | 1278 solves |
| Crypto on the Web | No Way JOSE | 20 | 1410 solves |
| Hash Functions | Jack's Birthday Hash | 20 | 938 solves |
| Hash Functions | Jack's Birthday Confusion | 30 | 893 solves |
| Crypto on the Web | Token Appreciation | 5 | 2176 solves |
| Crypto on the Web | JWT Sessions | 10 | 1756 solves |
| Mathematics | Cofactor Cofantasy | 150 | 250 solves |
| Symmetric Ciphers | Logon Zero | 80 | 397 solves |
| RSA | RSA Backdoor Viability | 175 | 460 solves |
| Misc | Jeff's LFSR | 150 | 139 solves |
| General | Transparency | 50 | 2265 solves |
| RSA | Let's Decrypt Again | 175 | 164 solves |
| Hash Functions | Twin Keys | 100 | 178 solves |
| Hash Functions | Invariant | 250 | 102 solves |
| Hash Functions | No Difference | 175 | 206 solves |
| Misc | Trust Games | 150 | 137 solves |
| Hash Functions | PriMeD5 | 100 | 232 solves |
| Mathematics | Ellipse Curve Cryptography | 125 | 278 solves |
| RSA | Let's Decrypt | 80 | 357 solves |
| Elliptic Curves | No Random, No Bias | 120 | 182 solves |
| Elliptic Curves | Edwards Goes Degenerate | 100 | 185 solves |
| Mathematics | Size and Basis | 15 | 2040 solves |
| Mathematics | Gaussian Reduction | 50 | 1269 solves |
| Mathematics | Find the Lattice | 100 | 695 solves |
Least Solved
| Category | Challenge | Points | Solves |
| Elliptic Curves | Real Curve Crypto | 200 | 26 solves |
| Symmetric Ciphers | Beatboxer | 150 | 43 solves |
| Hash Functions | MDFlag | 125 | 43 solves |
| Misc | LFSR Destroyer | 250 | 56 solves |
| Misc | Bruce Schneier's Password: Part 2 | 250 | 78 solves |
| Mathematics | No Way Back Home | 100 | 86 solves |
| Crypto on the Web | Saying Hello | 20 | 92 solves |
| Crypto on the Web | TLS Handshake | 15 | 95 solves |
| Crypto on the Web | Sharks on the Wire | 10 | 100 solves |
| Hash Functions | Invariant | 250 | 102 solves |
| Crypto on the Web | Secure Protocols | 5 | 111 solves |
| Diffie-Hellman | The Matrix Revolutions | 125 | 120 solves |
| Misc | Trust Games | 150 | 137 solves |
| Misc | Jeff's LFSR | 150 | 139 solves |
| RSA | Let's Decrypt Again | 175 | 164 solves |
| Misc | L-Win | 120 | 165 solves |
| Elliptic Curves | Double and Broken | 50 | 171 solves |
| Mathematics | Roll your Own | 125 | 173 solves |
| Hash Functions | Twin Keys | 100 | 178 solves |
| Elliptic Curves | No Random, No Bias | 120 | 182 solves |
| Elliptic Curves | Edwards Goes Degenerate | 100 | 185 solves |
| Misc | Nothing Up My Sleeve | 150 | 188 solves |
| Diffie-Hellman | The Matrix Reloaded | 100 | 189 solves |
| Symmetric Ciphers | Oh SNAP | 120 | 199 solves |
| Misc | Too Many Errors | 100 | 200 solves |