# Using Crc15 As Hash Function For Mac

**02**

The handle of the hash or MAC object to use to compute the hash or MAC. This handle is obtained by calling the BCryptCreateHash function. After this function has been called, the hash handle passed to this function cannot be used again except in a call to BCryptDestroyHash. The size, in bytes, of. Poker night 2 cheat. Using a rented Amazon AWS server with a fast graphics card, Mayer used the hash-checking program oclHashcat and was able to reverse the hash of his own cell phone’s MAC address in about 12 minutes.

As Chris Smith notes in the comments, HMAC is a specific MAC algorithm (or, rather, a method for constructing a MAC algorithm out of a ). Thus, HMAC can be used for any application that requires a MAC algorithm.

## Hash Function Calculator

One possible reason for requiring HMAC specifically, as opposed to just a generic MAC algorithm, is that the HMAC construction actually provides (as long as the underlying hash function satisfies the appropriate assumptions) stronger security properties than what's required of a MAC. Hva er boligen din verdt. For example, nothing in the definition of a secure MAC algorithm (resistance to existential forgery under a chosen-plaintext attack) says that the MAC output can't reveal information about the plaintext to an attacker. If the plaintext is secret but the MAC is public, that would obviously be bad. HMAC, however, is guaranteed not to reveal any information about the plaintext as long as the underlying hash function is secure. In particular, Bellare that HMAC is a as long as the compression function of the underlying hash is also a PRF, and a 'privacy-preserving MAC' (PP-MAC) as long as the compression function of the underlying hash is also a PP-MAC. Both of these are strictly stronger security properties than what's required of a plain MAC; in particular, being a PRF is a very strong security property — it essentially says that there's no practical way for an attacker to say anything about the output of the function based on the input, or vice versa, except for the obvious fact that the same input always yields the same output.

## Using Hash Function For Encryption

There are many use cases for which a PRF will do whereas a plain MAC may not; HMAC, instantiated with a secure hash function, can be used for those. Also, as Chris notes, some other MAC algorithms require a random IV to be secure; HMAC does not, so it can be used even in situations where deterministic output is required, or where messages must be kept as short as possible. As for why you might not want to use HMAC, well, one reason is that it's not really optimized for speed. /norton-internet-security-19-9-1-14-keygen-for-mac/. Dedicated MAC functions, particularly those based on universal hashing (the Carter–Wegman construction) like UMAC and VMAC, can be significantly faster. Also, MACs based on block ciphers (such as CMAC) can be very useful on limited platforms where an efficient block cipher primitive (like AES) is available but a secure hash function is not. Something else that has not been mentioned before: Remind the construction of a Merkle Damgard Hash with f the compression function (e.g.