Ciphers
Caesar
Shift every letter by N. Default 3, keyspace 25, and the attack is all of them.
Cipher / Shift
Caesar Cipher
Shift every letter by N.
- Keyspace
- 25
- Decode
- same options back
- Works on
- A-Z, the rest passes
- Family
- 3 in shift
required 0 / 1
Options
Access
- Create
create("caesar") - CLI
ciphers encode caesar 'ATTACK AT DAWN' --shift 3 - Tryplayground with the sample above
- Kinrot13, rot47
Every letter moves shift places down the alphabet and wraps from Z back to A. Default is 3, the one Suetonius says Caesar used. A shift is an integer from 1 to 25. Zero is the identity and 26 is zero again, both rejected.
import { create } from "@agntn/ciphers";
const caesar = create("caesar");
caesar.encode("ATTACK AT DAWN").text; // "DWWDFN DW GDZQ"
caesar.encode("Hello, World!", { shift: 7 }).text; // "Olssv, Dvysk!"
caesar.decode("DWWDFN DW GDZQ", { shift: 3 }).text; // "ATTACK AT DAWN"
Case survives, punctuation and spaces stay put. Decode with the wrong shift and you get another Caesar, which is why brute force exists: ciphers brute "KHOOR ZRUOG" prints all 25, and shift 3 reads HELLO WORLD.
ROT-13 is this with the shift nailed to 13.