argon2_cffi-16.3.0.tar.gz

# Argon2 [](https://travis-ci.org/P-H-C/phc-winner-argon2) [](https://ci.appveyor.com/project/P-H-C/phc-winner-argon2) [](https://codecov.io/github/P-H-C/phc-winner-argon2?branch=master) This is the reference C implementation of Argon2, the password-hashing function that won the [Password Hashing Competition (PHC)](https://password-hashing.net). Argon2 is a password-hashing function that summarizes the state of the art in the design of memory-hard functions and can be used to hash passwords for credential storage, key derivation, or other applications. It has a simple design aimed at the highest memory filling rate and effective use of multiple computing units, while still providing defense against tradeoff attacks (by exploiting the cache and memory organization of the recent processors). Argon2 has three variants: Argon2i, Argon2d, and Argon2id. Argon2d is faster and uses data-depending memory access, which makes it highly resistant against GPU cracking attacks and suitable for applications with no threats from side-channel timing attacks (eg. cryptocurrencies). Argon2i instead uses data-independent memory access, which is preferred for password hashing and password-based key derivation, but it is slower as it makes more passes over the memory to protect from tradeoff attacks. Argon2id is a hybrid of Argon2i and Argon2d, using a combination of data-depending and data-independent memory accesses, which gives some of Argon2i's resistance to side-channel cache timing attacks and much of Argon2d's resistance to GPU cracking attacks. Argon2i, Argon2d, and Argon2id are parametrized by: * A **time** cost, which defines the amount of computation realized and therefore the execution time, given in number of iterations * A **memory** cost, which defines the memory usage, given in kibibytes * A **parallelism** degree, which defines the number of parallel threads The [Argon2 document](argon2-specs.pdf) gives detailed specs and design rationale. Please report bugs as issues on this repository. ## Usage `make` builds the executable `argon2`, the static library `libargon2.a`, and the shared library `libargon2.so` (or `libargon2.dylib` on OSX). Make sure to run `make test` to verify that your build produces valid results. `make install PREFIX=/usr` installs it to your system. ### Command-line utility `argon2` is a command-line utility to test specific Argon2 instances on your system. To show usage instructions, run `./argon2 -h` as ``` Usage: ./argon2 [-h] salt [-i|-d|-id] [-t iterations] [-m memory] [-p parallelism] [-l hash length] [-e|-r] Password is read from stdin Parameters: salt The salt to use, at least 8 characters -i Use Argon2i (this is the default) -d Use Argon2d instead of Argon2i -id Use Argon2id instead of Argon2i -t N Sets the number of iterations to N (default = 3) -m N Sets the memory usage of 2^N KiB (default 12) -p N Sets parallelism to N threads (default 1) -l N Sets hash output length to N bytes (default 32) -e Output only encoded hash -r Output only the raw bytes of the hash -h Print argon2 usage ``` For example, to hash "password" using "somesalt" as a salt and doing 2 iterations, consuming 64 MiB, using four parallel threads and an output hash of 24 bytes ``` $ echo -n "password" | ./argon2 somesalt -t 2 -m 16 -p 4 -l 24 Type: Argon2i Iterations: 2 Memory: 65536 KiB Parallelism: 4 Hash: 45d7ac72e76f242b20b77b9bf9bf9d5915894e669a24e6c6 Encoded: $argon2i$v=19$m=65536,t=2,p=4$c29tZXNhbHQ$RdescudvJCsgt3ub+b+dWRWJTmaaJObG 0.188 seconds Verification ok ``` ### Library `libargon2` provides an API to both low-level and high-level functions for using Argon2. The example program below hashes the string "password" with Argon2i using the high-level API and then using the low-level API. While the high-level API takes the three cost parameters (time, memory, and parallelism), the password input buffer, the salt input buffer, and the output buffers, the low-level API takes in these and additional parameters , as defined in [`include/argon2.h`](include/argon2.h). There are many additional parameters, but we will highlight three of them here. 1. The `secret` parameter, which is used for [keyed hashing]( https://en.wikipedia.org/wiki/Hash-based_message_authentication_code). This allows a secret key to be input at hashing time (from some external location) and be folded into the value of the hash. This means that even if your salts and hashes are compromized, an attacker cannot brute-force to find the password without the key. 2. The `ad` parameter, which is used to fold any additional data into the hash value. Functionally, this behaves almost exactly like the `secret` or `salt` parameters; the `ad` parameter is folding into the value of the hash. However, this parameter is used for different data. The `salt` should be a random string stored alongside your password. The `secret` should be a random key only usable at hashing time. The `ad` is for any other data. 3. The `flags` parameter, which determines which memory should be securely erased. This is useful if you want to securly delete the `pwd` or `secret` fields right after they are used. To do this set `flags` to either `ARGON2_FLAG_CLEAR_PASSWORD` or `ARGON2_FLAG_CLEAR_SECRET`. To change how internal memory is cleared, change the global flag `FLAG_clear_internal_memory` (defaults to clearing internal memory). Here the time cost `t_cost` is set to 2 iterations, the memory cost `m_cost` is set to 2¹⁶ kibibytes (64 mebibytes), and parallelism is set to 1 (single-thread). Compile for example as `gcc test.c libargon2.a -Isrc -o test`, if the program below is named `test.c` and placed in the project's root directory. ```c #include "argon2.h" #include <stdio.h> #include <string.h> #include <stdlib.h> #define HASHLEN 32 #define SALTLEN 16 #define PWD "password" int main(void) { uint8_t hash1[HASHLEN]; uint8_t hash2[HASHLEN]; uint8_t salt[SALTLEN]; memset( salt, 0x00, SALTLEN ); uint8_t *pwd = (uint8_t *)strdup(PWD); uint32_t pwdlen = strlen((char *)pwd); uint32_t t_cost = 2; // 1-pass computation uint32_t m_cost = (1<<16); // 64 mebibytes memory usage uint32_t parallelism = 1; // number of threads and lanes // high-level API argon2i_hash_raw(t_cost, m_cost, parallelism, pwd, pwdlen, salt, SALTLEN, hash1, HASHLEN); // low-level API argon2_context context = { hash2, /* output array, at least HASHLEN in size */ HASHLEN, /* digest length */ pwd, /* password array */ pwdlen, /* password length */ salt, /* salt array */ SALTLEN, /* salt length */ NULL, 0, /* optional secret data */ NULL, 0, /* optional associated data */ t_cost, m_cost, parallelism, parallelism, ARGON2_VERSION_13, /* algorithm version */ NULL, NULL, /* custom memory allocation / deallocation functions */ /* by default only internal memory is cleared (pwd is not wiped) */ ARGON2_DEFAULT_FLAGS }; int rc = argon2i_ctx( &context ); if(ARGON2_OK != rc) { printf("Error: %s\n", argon2_error_message(rc)); exit(1); } free(pwd); for( int i=0; i<HASHLEN; ++i ) printf( "%02x", hash1[i] ); printf( "\n" ); if (memcmp(hash1, hash2, HASHLEN)) { for( int i=0; i<HASHLEN; ++i ) { printf( "%02x", hash2[i] ); }