Launch ABI-Coder and in the top section browse to the folder containing the file to encode. In the centre portion click the file to encode so it is highlighted. Now at the top left, type an encryption key of your choice in the box marked 'KEY' then type the same key again in the box marked 'CONFIRM,. Click the Encypt button and it's done. To decrypt a file follow the same procedure (entering the key you used to encrypt) then end by clicking the Decrypt button.