Message Integrity

Question 1

What is hashing?

Answer 1

Hashing refers to the mathematical transformation of data using an algorithm whose result is predictable, repeatable and entirely dependent upon the content of the message and of a fixed length. Used when a sender wants to ensure a message is not affected by noise or network problems. He or she can hash the message and send the digest along with the message to the receiver.

Question 2

Digital Signatures

Answer 2

Combines a hash function with the asymmetric encryption ability to verify the author’s identity. Only a message that is both signed and encrypted is afforded confidentiality, integrity, and non-repudiation.

Question 3

Certificates

Answer 3

The purpose of a certificate is to link a public key with a specific owner by relying on the verification of a trusted third-party known as a certification authority (CA). The CA generates a certificate on behalf of the owner of a public key that the owner can use to prove that the public key belongs to them. It is valid for a defined period of time, usually one year.

Question 4

Public Key Infrastructure

Answer 4

PKI refers to the overall implementation of public key cryptography, including certificates and the CAs needed to issue and verify them.