Encodings
Here is a non-exhaustive list of many common and useful encodings you’ll encounter quite often in computer science, cybersecurity, and CTF events.
Quick reference
| Encoding | Alphabet / Structure | Recognition Hints |
|---|---|---|
| Base64 | A–Z a–z 0–9 +/ = | Ends with = / ==. ASCII letters + slashes |
| Base32 | A–Z 2–7 = | Uppercase letters and digits 2–7, often ends with = |
| Base58 | 1–9 A–H J–N P–Z a–k m–z (BTC alphabet) | No +/=, mixed case letters & digits |
| Base85 / Ascii85 | <~ !–u ~> | <~ prefix, uses ASCII 33–117 |
| Base92 | A–Z a–z 0–9 !"#$%&'()*+,./:;<=>?@[\]^_{|}~` | No padding, 92 printable chars |
| Hex | 0–9 A–F (pairs) | Even length, only hex digits |
| Binary (ASCII) | 0 1 (8‑bit groups) | Only 0s and 1s, usually multiple of 8 |
| Octal | 0–7 (groups of 3) | Digits 0–7, often separated by spaces |
| Unicode/UTF‑8 | Variable-length (1–4 bytes per char) | Non-ASCII chars appear as multi-byte sequences |
| Unicode/UTF‑16 | h\x00i\x00 (null bytes between letters) | Appears in hexdumps/UTF‑16 files |
| Morse Code | . - (separated by spaces) | Only . and - separated by spaces |
| URL Encoding | %00–%FF (hex pairs) | %-prefixed hex pairs (e.g., %20 for space) |
| HTML Entities | &name; or &#ddd; | Starts with & and ends with ; |
Examples
Here is the text example represented in all the encodings described above.
| Encoding | Example |
|---|---|
| Base64 | ZXhhbXBsZQ== |
| Base32 | MV4GC3LQNRSQ==== |
| Base58 | 4r2UmqYWb6 |
| Base85 / Ascii85 | AU%X#E,9( |
| Base92 | Ea&;bv5'6 |
| Hex | 252f6578616d706c65 |
| Binary (ASCII) | 001001010010111101100101011110000110000101101101011100000110110001100101 |
| Octal | 45 57 145 170 141 155 160 154 145 |
| Unicode/UTF‑16 | \u0065\u0078\u0061\u006d\u0070\u006c\u0065 |
| Morse Code | . -..- .- -- .--. .-.. . |
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