The password tool creates new, 256-bit AES-encrypted password strings for use with iMacros. Just enter your master password, the password to encrypt and press the "Encrypt" button.
This password tools works with all new iMacros versions: iMacros for Firefox V6.5 and later, iMacros for Chrome V1.0.4 and later and the iMacros Browser / iMacros for IE V7.00 and later.
You can download and inspect the open-source encryption code (enc.js and rijndael.js).
For more information about the iMacros password encryption please see the Wiki: