playfair_cipher

Implementation of the PlayFair cipher - nothing special, nothing useful, just for fun.

Encrypt

```rust use playfair_cipher::{PlayFairKey, CharNotInKeyError};

let pfc = PlayFairKey::new("playfair example"); match pfc.encrypt("hide the gold in the tree stump") { Ok(crypt) => { assert_eq!(crypt, "BMODZBXDNABEKUDMUIXMMOUVIF"); } Err(e) => panic!("CharNotInKeyError {}", e), }; ```

Decrypt

```rust use playfair_cipher::{PlayFairKey, CharNotInKeyError};

let pfc = PlayFairKey::new("playfair example"); match pfc.decrypt("BMODZBXDNABEKUDMUIXMMOUVIF") { Ok(crypt) => { assert_eq!(crypt, "HIDETHEGOLDINTHETREXESTUMP"); } Err(e) => panic!("CharNotInKeyError {}", e), }; ```

That's it.