Data Encryption Software

Hi , i need a data encryption software to be built for windows. how will the system work : - there will be a usb device , which will have the code. when you insert the usb device , and open the software, you will be able to encrypt some files , and keep them on your computer encrypted without having the software installed in the computer. you will be able to encrypt files on every computer you insert the usb device. key points are : 1- the software wont be installed on the computer, it will just stay on the usb device 2- the created file will be encrypted, and cant be seen or read without inserting the usb device. 3- the software wont make portions at c disk, the files kept on computer will be totally invisible 4- the encrypted files or the software wont leave any trace, even the computer is searched by legal orginazations. 5- if the encrypted file is found , it must be impossible to decrypt. The bidder : 1- he must be familiar with 256 bit AES algorithm 2- he must have worked or managed on this kind of software before 3- he must state which software language he will use 4- he must give some referance Please send your bid and a mesaage , in your message please give more deatails about yourself, and your thoughts about our project. Please give a exact time frame and budget to complete the project. regards