By Qualia765
Input plaintext and key.
Press Encrypt.
Send ciphertext as message.
Send key secretly.
Input ciphertext and key.
Press Decrypt.
Plaintext is you message.
Get some reference text (multiple paragraphs of any text).
Put reference text into the reference box.
When decrypting, this text will be convereted into character counts,
which is more efficent to store if you wish to save it then what was inputed.
Set the key to any value, but with the length the text was encrypted with.
If you don't know the key length, start with a length of 1.
Input ciphertext.
Press Crack.
If resulting plaintext is completly wrong, the key is probably the wrong size.
If the plaintext is even partly wrong the key length is correct.
Substitue individual characters to fix varrious parts.
Maybe use the suggested second choice options listed for replacement ideas