README.md

Crypto

Small, fast, header only, zero dependency cryptographic library written in C++2a.

Cryptographic hash functions

Cryptographic Hash Functions (CHFs) are a family of algorithms that take an input (or message) and produce a fixed-size output, known as the hash value or digest. This process is a one-way function, meaning it is computationally infeasible to reverse the hash value to obtain the original input. Additionally, small changes in the input will result in significantly different hash values.

Algorithms

Class	Word bits	Size bits	Block bits	Rounds	State bits	Output bits
MD4	32	64	512	3	128	128
MD5	32	64	512	64	128	128
RMD<128>	32	64	512	64	128	128
RMD<160>	32	64	512	80	160	160
RMD<256>	32	64	512	64	256	256
RMD<320>	32	64	512	80	320	320
SHA1	32	64	512	80	160	160
SHA2<256,224>	32	64	512	64	256	224
SHA2<256,256>	32	64	512	64	256	256
SHA2<512,224>	64	128	1024	80	512	224
SHA2<512,256>	64	128	1024	80	512	256
SHA2<512,384>	64	128	1024	80	512	384
SHA2<512,512>	64	128	1024	80	512	512

Examples

Double hashing the contents of a container holding trivially copyable objects with the help of SHA2<256> and RMD<160>. Note that rmd<160>(message) is an alias for RMD<160>().update(message).digest().

#include <crypto/rmd.h>
#include <crypto/sha2.h>

using namespace crypto;

auto
hash(const auto &trivially_copyable_objects) {

    auto hasher = SHA2<256>();

    for (const auto &entry: trivially_copyable_objects) {
        hasher.update(entry);
    }

    return rmd<160>(hasher.update("secret").digest());
}

Message authentication codes

Message Authentication Codes (MACs) are cryptographic mechanisms used to ensure the integrity and authenticity of a message or data transmission. They provide a way to verify that a message has not been tampered with during transmission and that it originates from a trusted source.

Algorithms

Only the hash-based message authentication code (HMAC) is supported at the moment.

Examples

Double hashing the contents of a container holding trivially copyable objects with the help of HMAC, SHA2<256> and RMD<160>. Note that hmac<RMD<160>>(secret, message) is an alias for HMAC<RMD<160>>(secret).update(message).digest().

#include <crypto/rmd.h>
#include <crypto/sha2.h>
#include <crypto/hmac.h>

using namespace crypto;

auto
hash(const auto &trivially_copyable_objects) {

    auto hasher = HMAC<SHA2<256>>("secret 1");

    for (const auto &entry: trivially_copyable_objects) {
        hasher.update(entry);
    }

    return hmac<RMD<160>>("secret 2", hasher.digest());
}

Installation

Download the sources to the folder of choice and include the desired headers.

Contributing

Feature requests, bug reports and success stories are most welcome.

Copyright

Copyright 2018 Quasis - The MIT License