Security : Digital Signature

A digital signature is a binary code that uniquely identifies a person. Digital signatures are used to improve the security of sending messages by email. Two particular problems with using email are :

• It is difficult to determine if a message you receive has actually come from the person it says it has.
• The content of messages can be changed by unauthorised people as they are transmitted.

You can get a digital signature from an issuing authority such as VeriSign or you can make your own up (but this is less secure). If you have a digital signature then when you send an email you can add it to the end of the email.

When the email is received the recipient will be able to verify that the message came from the person that supposedly sent it by checking the message's digital signature. Digital signatures also allow the recipient to check if the message has been altered at all since it was sent.

GCSE ICT Companion 04 - (C) P Meakin 2004