Keyword cipher
Please note that these tools aren't optimized for large amounts of data, processing can slow down or run into problems once you reach above 150,000 characters. A cap of 1 million characters is currently in place.
Keyword cipher
Similar to the Vigenère cipher (the decryption process is the same), except you start with a reversed alphabet. For example:
Hello World encrypted with a key of Test would shift like:
Eckkn Unqkb
Keyword cipher