Web form input decryption error

Hi,

I have a Web form build with Adobe Campaign Web Application.

I encrypted the input field data with crypteString(ctx.table_name.field_name) and found out that it gets different results everytime.

I also got an error message when I decrypt the cipertext with decryptString(ctx.table_name.field_name)

Anyone knows how to encrypt and decrypt a field from the table properly or should I write my own function?