What is a Message Digest or Hash Value?
A message digest or hash value is a numeric string generated using the cryptographic hash function. The message string is passed to the hash function. Hash function computes a unique hash value for the provided message and this hash value acts as digital fingerprint of the message.
The cryptographic function creates the message digest, which may then be encrypted to give a second layer of security. This function is one-way; it can only be used to generate the message digest from the message, not the other way around. If the message digest is created using a symmetric key then it is known as MAC or Message Authentication Code. Encrypted message digests work as digital fingerprints and the receiver needs to decrypt the digests first to compare them.
What is Message and Message Digest in Cryptography?
A Message is any information that flows via the network, such as files, emails, and financial transactions, from one device to another or from a set of devices. When a message is sent over a network, it must be secure to ensure that it is safe from anybody sitting in the middle listening to the conversation and having the ability to access, alter, or modify the message.