CRYPTOGRAPHY - Hashing

Contents

Hashing introduction

Hashing types

Discussion

Merkle-Damgaard

The Merkle-Damgaard construction is a method of building collision-resistant cryptographic hash functions from collision-resistant one-way compression functions. This construction was used in the design of many popular hash algorithms such as MD5, SHA-1 and SHA-2. It was described in Ralph Merkle's Ph.D. thesis in 1979. Ralph Merkle and Ivan Damgård independently proved that the structure is sound: that is, if an appropriate padding scheme is used and the compression function is collision-resistant, then the hash function will also be collision-resistant.

Sponge

At a glance:

Other

At a glance:

Algorithms

Discussion

Standards

Refer also to crypto standards.

Bear in mind that NIST publishes the Secure Hash Standard (SHS) as NIST FIPS 180-4, which includes SHA-1 and SHA-2.

RIPEMD

SHA-1, SHA-2, SHA-3

Multihash

Multihash is a protocol for differentiating outputs from various well-established hash functions, addressing size and encoding considerations. It is useful to write applications that future-proof their use of hashes, and allow multiple hash functions to coexist.

Key derivation

A key derivation function (KDF) is a cryptographic hash function that derives one or more secret keys from a secret value such as a main key, a password, or a passphrase using a pseudorandom function. KDFs can be used Keyed cryptographic hash functions are examples of pseudorandom functions used for key derivation