Final Exam / Answer No. 1

E-mail Security School Final Exam / Answer No. 1

1.) When are digital signatures and footer stamping incompatible?

A digital signature is something stamped onto a message by the sender. The signature is a cryptographic operation, usually a hash, across the message content, which is then locked with the private key of the sender. The recipient can use the sender's public key to compare a hash they compute with the transmitted hash to see if the message has been tampered with, or isn't from the purported sender at all.

Injecting a footer into a message after it is signed by the sender will invalidate the digital signature. As a result, all recipients of the message think that the message has been tampered with or was forged. If you want to digitally sign messages and have footers, then you need to put the footer into the message before the sender adds their digital signature.

<< Back to quiz

This was first published in April 2005

Dig deeper on Email Security Guidelines, Encryption and Appliances

Pro+

Features

Enjoy the benefits of Pro+ membership, learn more and join.

0 comments

Oldest 

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

-ADS BY GOOGLE

SearchCloudSecurity

SearchNetworking

SearchCIO

SearchConsumerization

SearchEnterpriseDesktop

SearchCloudComputing

ComputerWeekly

Close