Cryptography
cryptobeginner
Index of all crypto pages - from classical ciphers through RSA, ECC, AES, hashing, and XOR.
cryptocryptographyindexoverview
Cryptography
CTF crypto challenges range from simple classical ciphers to modern asymmetric, symmetric, hashing, and XOR problems. Start with encoding/decoding basics and work your way upward through the section.
Pages in This Section
| Page | Difficulty |
|---|---|
| Encoding vs Encryption vs Hashing | Beginner |
Quick Identification Guide
Use this table to quickly triage an unknown crypto challenge. Start with the most observable property of the ciphertext.
| Observation | Technique |
|---|---|
| All letters, shifts by same amount? | Caesar / ROT13 |
| All letters, key repeats? | Vigenère |
| Letters rearranged? | Transposition |
| , letters substituted? | Monoalphabetic substitution |
| Base64/hex blob? | Encoding - just decode |
| ciphertext? | RSA - use RsaCtfTool |
| XOR'd data? | XOR crypto, find key via known plaintext |
| AES with same IV? | ECB / nonce-reuse attack |
| Server reveals padding error? | Padding oracle |
Tools Quick Reference
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