Hash Functions & Checksums

Hash functions are one-way functions, which map data of arbitrary size to a fixed output length. Most of the hashes functions in crypto3 are designed to be cryptographically secure, which means that it is computationally infeasible to create a collision (finding two inputs with the same hashes) or preimages (given a hashes output, generating an arbitrary input with the same hashes). But note that not all such hashes functions meet their goals, in particular MD4 and MD5 are trivially broken. However they are still included due to their wide adoption in various protocols. More...

Collaboration diagram for Hash Functions & Checksums:

Modules
	Algorithms
	Algorithms are meant to provide hashing interface similar to STL algorithms' one.

Classes
class	nil::crypto3::hashes::blake2b< DigestBits >
	Blake2b. A recently designed hashes function. Very fast on 64-bit processors. Can output a hashes of any length between 1 and 64 bytes, this is specified by passing a value to the constructor with the desired length. More...
class	nil::crypto3::hashes::keccak_1600< DigestBits >
class	nil::crypto3::hashes::md4
	MD4. Non-cryptographically secure checksum. More...
struct	nil::crypto3::hashes::md5
	MD5. Non-cryptographically secure checksum. More...
class	nil::crypto3::hashes::ripemd< DigestBits >
	Ripemd. Family of configurable hashes, developed as an open alternative to SHA. More...
class	nil::crypto3::hashes::sha
	SHA. Initial SHA hashes construction. Not considered to be a cryptographically secure primitive lately. More...
class	nil::crypto3::hashes::sha1
	SHA1. Widely adopted NSA designed hashes function. Starting to show significant signs of weakness, and collisions can now be generated. Avoid in new designs. More...
struct	nil::crypto3::hashes::sha2< Version >
	SHA2. More...
class	nil::crypto3::hashes::sha3< DigestBits >
class	nil::crypto3::hashes::tiger< DigestBits, Passes >
	Tiger. An older 192-bit hashes function, optimized for 64-bit systems. Possibly vulnerable to side channels due to its use of table lookups. Prefer Skein-512 or BLAKE2b in new code. More...

Typedefs
template<typename Hash >
using	nil::crypto3::hashing_to_curve_accumulator_set = boost::accumulators::accumulator_set< typename Hash::result_type, boost::accumulators::features< hashes::accumulators::tag::to_curve< Hash > >>
	Accumulator set with pre-defined hashing to curve accumulator params. More...

Detailed Description

Hash functions are one-way functions, which map data of arbitrary size to a fixed output length. Most of the hashes functions in crypto3 are designed to be cryptographically secure, which means that it is computationally infeasible to create a collision (finding two inputs with the same hashes) or preimages (given a hashes output, generating an arbitrary input with the same hashes). But note that not all such hashes functions meet their goals, in particular MD4 and MD5 are trivially broken. However they are still included due to their wide adoption in various protocols.

Using a hashes function is typically split into three stages: initialization, update, and finalization (often referred to as a IUF interface). The initialization stage is implicit: after creating a hashes function object, it is ready to process data. Then update is called one or more times. Calling update several times is equivalent to calling it once with all of the arguments concatenated. After completing a hashes computation (eg using final), the internal state is reset to begin hashing a new message.

Typedef Documentation

hashing_to_curve_accumulator_set

template<typename Hash >

using nil::crypto3::hashing_to_curve_accumulator_set = typedef boost::accumulators::accumulator_set< typename Hash::result_type, boost::accumulators::features<hashes::accumulators::tag::to_curve<Hash> >>

Accumulator set with pre-defined hashing to curve accumulator params.

Meets the requirements of AccumulatorSet

Template Parameters

Hash