Difference between Hash Function and MAC (2024)

FAQs

What is the difference between hash function and MAC? ›

A message authentication code (MAC) is similar to a cryptographic hash, except that it is based on a secret key. When secret key information is included with the data that is processed by a cryptographic hash function, the resulting hash is known as an HMAC.

Security. While MAC functions are similar to cryptographic hash functions, they possess different security requirements. To be considered secure, a MAC function must resist existential forgery under chosen-message attacks.

This example also shows that a CBC-MAC cannot be used as a collision-resistant one-way function: given a key it is trivial to create a different message which "hashes" to the same tag.

A hash is a fixed-length string of characters that is created from a longer message or data, Hashing is the process of creating a hash, and a hash function is the specific algorithm used to create the hash.

HMAC (Hash Message Authentication Code) functions are cryptographic functions which are used to validate the authenticity (and so integrity) of a message. The MAC function consists in transforming a long data (called message) in a small message (called MAC) using a hash function and a cryptographic secret key.

Hash functions are used in conjunction with hash tables to store and retrieve data items or data records. The hash function translates the key associated with each datum or record into a hash code, which is used to index the hash table.

Because there are fewer Apple products compared to PCs, there are fewer viruses created for OS X. In addition, because Apple tightly controls the software on its devices, there is much less bloatware installed on new systems. Apple's customer service is well known for being better.

The HMAC construction enhances the security of MACs by incorporating additional steps in the computation of the tag. It provides resistance against certain types of attacks and offers a higher level of security assurance compared to traditional MAC algorithms.

To protect passwords, experts suggest using a strong and slow hashing algorithm like Argon2 or Bcrypt, combined with salt (or even better, with salt and pepper). (Basically, avoid faster algorithms for this usage.) To verify file signatures and certificates, SHA-256 is among your best hashing algorithm choices.

Since encryption is two-way, the data can be decrypted so it is readable again. Hashing, on the other hand, is one-way, meaning the plaintext is scrambled into a unique digest, through the use of a salt, that cannot be decrypted.

Why CBC-MAC is insecure if a random IV is used? ›

This is so because if we XOR the first block with random IV before it first comes into contact with the block cipher, then changing only the first block together with a corresponding change in IV may yield into same authentication tag as earlier, thus breaking the CBC-MAC scheme.

The problem with CBC mode is that the decryption of blocks is dependant on the previous ciphertext block. This means attackers can manipulate the decryption of a block by tampering with the previous block using the commutative property of XOR.

Essentially, MAC is an algorithm that takes, as input, a message combined with a shared secret key. Let's continue with a conceptual comparison where we define security goals for both processes. Hash functions are used to ensure data integrity. Any change in the original message results in generating a different Hash.

The most common hash functions used in digital forensics are Message Digest 5 (MD5), and Secure Hashing Algorithm (SHA) 1 and 2.

HMAC is a specific construction for MACs that is based on a cryptographic hash function. It provides enhanced security compared to traditional MAC algorithms by incorporating additional steps in the computation of the tag. The main difference between a MAC and HMAC lies in the way the tag is computed.

They are message encryption, message authentication code, and hash functions. The major difference between MAC and hash (HMAC here) is the dependence of a key. In HMAC we have to apply the hash function along with a key on the plain text. The hash function will be applied to the plain text message.

Encryption techniques protect data in motion. Hashing protects data at rest. Combining these strategies could, in theory, put a strong security boundary around critical assets. But both come with risks and benefits you should know about.