One Time Pad Encryption Tool
EncryptKey is a free and efficient windows software which allows you to encrypt any file using unbreakable one time pad encryption.
What is One Time Pad Encryption?
One Time Pad encryption is an unbreakable encryption technique which applies a "random" modification to every bit of data in a file. This tool saves the encrypted data as a new file, and the encryption data in a separate file of equivalent size.
Read more @ Wikipedia - One-Time Pad
How does EncryptKey work?
Once you choose the file to encrypt, the program will ask you for a location to store a .key and a .pad file created from your original. This tool will leave your original file intact. Make sure to delete the original securely if you want to prevent it from being recovered.
For this to be effective the files need to be physically separated as anyone with both pieces can put the original back together. If you place either file in another location (flash drive, another computer system) anyone who does not know the location of or possess both files cannot under any circumstances unencrypt your data. Keep in mind both pieces are necessary to get your data back.