Looking for an encoder/decoder program

[Akisa]

I'm looking for a program where I can type out a sentence that would encode it in a method that replaces letters with another letter.

For example replacing A with would cause this sentence to read from
"I went to the park today"

to

"Q enva aw aqn xiys awlig"

[Tirian]

http://cryptoclub.math.uic.edu/substitutioncipher/sub2.htm seems like a very quick and dirty online tool. If you had some programming language or other installed on your computer, we could probably write programs to make it even easier for you if you were out to encrypt a lot of text or text in a lot of different ciphers, but this would be enough to get you started.

[Swordgleam]

I have one on my site that does that: http://chaoticshiny.com/langreplace.php

You can choose from a couple different ones, or random. It's designed for people who want fantasy-sounding gibberish in their stories, but it would probably work just as well for what you want.