Pixel Cryptor is an encryption program that enables you to create encrypted archives containing one or more files, and protect the content without the need to remember any password. Instead of a password or key, the program uses an image file (any image) and generates a checksum from it, which acts as your key to lock and unlock the files in the archive.
If you share the archive by email (or other means), the receiver needs to have a copy of the Pixel Cryptor software installed, as well as an exact duplicate of the image you used to encrypt the archive. To unlock an encrypted file, simply select the proper image when prompted and the content will be revealed. While this may sound very convenient, you should be aware that the slightest change to the original image (e.g editing, renaming), or loss of the image will leave your encrypted data inaccessible. Encryption algorithm not disclosed by the author.