Again, it's believed to be difficult to generate or tamper with a message and/or its signature and still make one match the other, without knowing the generation key.
#What is the equivalent of word on a mac verification
The verification key is "public" you can spray-paint it on your car and drive it into the middle of DEF CON (hacker convention) and it would not make the scheme any weaker. There are known ways to share this key with one and only one other specific person, but it's this sharing process that allows you to positively identify the other person using the key the algorithm itself has no way to demonstrate to either party that the other person is the one who is supposed to have it.ĭigital signatures, OTOH, are asymmetric two different keys are used, one to generate and the other to verify.
:max_bytes(150000):strip_icc()/001_enable-track-changes-word-for-mac-3540065-ad388f75d0964b7d9c94d445bd4c191a.jpg "what is the equivalent of word on a mac")
However, because the key to a symmetric algorithm is a "shared secret", it has to be shared, and that means it isn't really a secret.
#What is the equivalent of word on a mac mac
As such, they verify that the message containing the MAC is the message originally sent by the other party to this conversation, because being able to tamper with the message in a way that the MAC would still match is believed to be difficult (and "difficult" in cryptography has the colloquial definition of "practically impossible"). Back to Thomas's post, MACs are symmetric they use the same key K both to generate the MAC and to verify it. The difference is inherent in the symmetric vs asymmetric structure of the algorithms. A signature verifies not only the message integrity, but the sender's identity. The short of it is that a MAC can be used only to verify the integrity of the message. Thomas Pornin's answer, as always, is excellent, but I wanted to add a point, and that was the difference in what verification of each of these represents. But this does not give you the power to issue (sign) certificates yourself, which would appear as if they were issued by Verisign/Thawte/whatever. Everybody, and in particular your Web browser, can verify that the certificate issued to the SSL server has indeed been signed by Verisign/Thawte/whatever. Signatures are when you want to produce a proof verifiable by third party without having to entrust these third parties with anything.Īpplication: a CA (like Verisign or Thawte or whatever) issues a certificate to a SSL server. With signatures, you can make the verification key public, while keeping the generation key private. With a MAC, any entity who can verify a MAC value necessarily has the power to generate MAC values of its own. Thus, signatures dissociate the generation and verification powers.
With a signature, the verification key K 2 is mathematically linked with K 1 but not identical, and it is unfeasible to recompute K 1 from K 2 or to generate valid signatures when you only know K 2. With a MAC, keys K 1 and K 2 are identical (or can be trivially recomputed from each other). Verification: given the message m, a key K 2 and the MAC value or signature s, verify that they correspond to each other (the MAC value or signature is valid for the message m, using verification key K 2).Generation: given the message m and a key K 1, compute the MAC value or signature s.In both MAC and digital signature schemes, you have two algorithms:
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