intercept an email message and tamper with the contents of the email the black hat then could modify any part of a message this kind of tampering is known as a u201c man in the middle u201d mitm attack the tamper proof mechanism of the present application in one embodiment addresses this problem for example by validating the email message signature via a tpd thus enforcing the data integrity of the message tpd in one embodiment is a base 64 encoded tamper proof digest which is a brand validation signature in one embodiment the tamper proof mechanism tpd generation validation provides a trust mechanism for brand mail there are many existing industry strength mechanisms that perform email cryptographic operations such as ssl tls s mime and pgp u2014 pki solutions the pki solutions listed above can also be used to secure brand mail messages however the present application provides an optional high performance lightweight symmetric key cryptographic system based on dynamic algorithmic selection based on a generated algorithm index it is left to the organizations communicating for example those exchanging brand mails to configure their brand mail system for cryptographic communication fig1 is an architectural diagram illustrating an overview of a brand mail system of the.