Crypto lab oneway hash function and mac answers

Find centralized, depended on content and collaborate around the technologies you use maximum.

Q&A for work

Connect and proportion knowledge inside a unmarried place that is structured and clean to search.

crypto lab   oneway hash function and mac answers

What is the Difference between a Hash and MAC (Message Authentication code)?

By their definitions they seem to serve the equal characteristic.

Can a person explain what the distinction is?

The most important distinction is conceptual: while hashes are used to guarantee the choices integrity of data, a MAC guarantees integrity AND authentication.

This means that a hashcode is blindly generated from the message with none form of external enter: what you bought is something that may be used to test if the choices message got any alteration all through its journey.

A MAC instead makes use of a non-public key as the seed to the hash feature it makes use of while producing the choices code: this ought to guarantee the choices receiver that, no longer only the choices message hasn’t been modified, however additionally who despatched it is what we have been expecting: otherwise an attacker couldn’t know the choices non-public key used to generate the code.

According to wikipedia you’ve got that:

While MAC features are just like cryptographic hash features, they own one of a kind safety requirements. To be considered secure, a MAC function need to resist existential forgery below selected-plaintext assaults. This method that even supposing an attacker has get right of entry to to an oracle which possesses the secret key and generates MACs for messages of the choices attacker’s choosing, the choices attacker cannot bet the choices MAC for other messages without appearing infeasible quantities of computation.

Of route, even though their similarities, they’re applied in a specific way: normally a MAC technology algorithm is based totally upon a hash code era algorithm with the extension that cares approximately the use of a non-public key.

A hash is a characteristic that produces a digest from a message. A cryptographically secure hash is for which it is computationally infeasible to generate a message with a given digest. On its personal a hash of a message gives no records approximately the sender of a given message. If you could securely speak the choices hash of a message then it could be used to verify that a big message has been efficiently received over an unsecured shipping.

A message authentication code is a way of mixing a shared mystery key with the choices a message in order that the choices recipient of the choices message can authenticate that the choices sender of the choices message has the choices shared mystery key and the choices no-one that does not understand the choices secret key may want to have sent or altered the message.

An HMAC is a hash-primarily based message authentication code. Usually this includes applying a hash function one or more times to some form of combination of the shared mystery and the choices message. HMAC normally refers the choices the algorithm documented in RFC 2104 or FIPS-198.

A MAC does not encrypt the message so the choices message is in undeniable textual content. It does no longer screen the choices secret key so a MAC may be despatched throughout on open channel without compromising the key.

Found this to the choices factor answer from any other forum.

These forms of cryptographic primitive can be prominent with the aid of the safety goals they satisfy (in the simple protocol of “appending to a message”):

Integrity: Can the recipient be confident that the message has not been by accident modified?

Authentication: Can the choices recipient be confident that the choices message originates from the sender?

Non-repudiation: If the choices recipient passes the choices message and the choices proof to a third birthday party, can the choices 1/3 birthday party be assured that the message originated from the sender? (Please notice that I am talking approximately non-repudiation in the cryptographic feel, now not within the prison sense.) Also crucial is this query:

Keys: Does the choices primitive require a shared secret key, or public-non-public keypairs? I think the fast solution is best defined with a table:

Please keep in mind that authentication without confidence inside the keys used is vain. For digital signatures, a recipient need to be assured that the verification key without a doubt belongs to the sender. For MACs, a recipient ought to be confident that the choices shared symmetric key has simplest been shared with the sender.

Click right here for greater data

HASH FUNCTION: A feature that maps a message of any duration into a fixed length hash cost, which serves as the choices authenticator.

MAC: A function of the choices message and a secret key that produces a hard and fast duration value that serves as the choices authenticator.

Basically the main distinction is MAC uses a private key and hash does now not use any keys. Because of that MAC lets in us to achieve authentication.

A Hash is a summary or a finger print of a message and provide neither integrity nor authentication itself, as is it is susceptible to man-in-the choices-center assault. Suppose A wants to send a message M, mixed with hash H of M, to B. Instead C seize the message and generate Message M2 and hash H2 of M2, and sends it to B. Now B, by way of no suggest can affirm whether that is the original message from A or now not. However, hash can be used in some other approaches to acquire integrity and authentication, including MAC.

A MAC which is likewise a precis of the choices message offer Integrity and Authentication. MAC can be computed in many methods. The most effective approach is to use a hash feature with two inputs, the choices message and a shared secret key. The use of the choices shared secret key adds the choices Authentication potential to the choices MAC, and hence provide integrity and authentication. However, MAC nonetheless does no longer offer non-repudiation, as any of the choices birthday party(es) having the shared mystery key can produce the message and MAC. Here comes the choices Digital Signature and Public Key Cryptography in movement.

Your Answer

Thanks for contributing an answer to Stack Overflow!

To analyze extra, see our hints on writing awesome solutions.

Required, but never proven

Required, but in no way proven

By clicking “Post Your Answer”, you compromise to our terms of service, privacy coverage and cookie policy

Not the answer you're searching out? Browse different questions tagged hash cryptography terminology or ask your personal query.

site design / emblem © 2021 Stack Exchange Inc; consumer contributions licensed under cc by means of-sa. rev 2021.11.5.40661

By clicking “Accept all cookies”, you agree Stack Exchange can shop cookies for your tool and expose facts according with our Cookie Policy.