1. A method, comprising: receiving a message that includes a document and an encrypted access code; in response to opening of the message, generating an image having embedded information that includes the encrypted access code; capturing a copy of the image at a portable device; decrypting the encrypted access code from the copy of the image using information stored in the portable device to yield a decrypted access code; and generating an output that includes the decrypted access code, the output allowing access to the document.