encrypt/decrypt URI

I think the AES key must be hex characters. If the jsessionid isn't made up of only hex characters, you could convert it to hex:

 
     Save a test string 
    set key_string "a b . *^&E^ d asdfasdfasdf " 
  
     Convert the test string to hex 
    binary scan $key_string H* key_hex 
    log local0. "\$key_hex: $key_hex" 
  
     Encrypt another test string with the key in hex 
    set encrypted [AES::encrypt $key_hex "test123"] 
  
     Log the decrypted value 
    log local0. "decrypted: [AES::decrypt $key_hex $encrypted]" 
 

Or you could use a single key to encrypt the content for all users.

Aaron