Kryptomate

Kryptomate is an app to help you en- or decode small text snippets through either Caesar or Vigenère cipher. Be it for a puzzle (e.g. for a Geocache) or for fun with your friends.
The caesar cipher is probably the simplest and most well-known cipher out there. It works by shifting each letter of the given phrase forward in the alphabet by a given number. It is named after Julius Caesar, who was known for encrypting sensitive military information with a shift of three.
The caesar cipher is often used to teach the basics of cryptography, as it's purpose and function is easily understood.
The vigenère cipher works using the same principle, but is significantly younger and it took quite a while for the first person to break it. It uses a key instead of a single shift to determine a different shift for each letter of the given phrase. Doing so makes it a lot harder for a single person to try and break it by guessing the shift.
The ciphers used in Kryptomate are in no way something you should use to keep actual data safe. Even the newer of the two methods is over 450 years old. The caesar and vigenère ciphers are both very simple concepts and often used in puzzles. Both are not secure for modern purposes.
Please note that Kryptomate will only work with alphabetical characters (A-Z, a-z). Punctuation, numbers and other special characters will stay the same.
The source for this application is available on Github. See https://github.com/kiliankoe/kryptomate-ios