NuHash/README.md
2023-06-25 15:31:00 +02:00

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![](etc/images/nuhash_logo.png)
Introduction
============
**NuHash** is a fast, portable and secure hashing library, released under the CC0 license.
The "core" library (*libnuhash*) is written in pure **C99**, but a high-level wrapper for **C++** is also provided.
Supported platforms include Linux, Windows, *BSD, Illumos, Haiku OS, GNU Hurd and MacOS X.
Getting Started
===============
The following example shows how to use the *libnuhash* “stream” API in C99 code:
```c
#include <nuhash.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
/* state variables */
nuhash_t context;
uint8_t buffer[BUFSIZ], digest[NUHASH_BYTES];
char hexstr[NUHASH_CHARS];
/* initialization */
nuhash_init(&context);
/* input data processing */
while(more_data())
{
const size_t len = read_data(buffer, BUFSIZ);
nuhash_update(&context, buffer, len);
}
/* finalization */
nuhash_final(&context, digest);
/* print the result */
puts(nuhash_tohex(digest, 0, hexstr));
}
```
If all input data is available at once, the *libnuhash* “simple” API can be used instead:
```c
#include <nuhash.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
/* state variables */
uint8_t digest[NUHASH_BYTES];
char hexstr[NUHASH_CHARS];
/* compute hash */
nuhash_compute(get_data(), length(), digest);
/* print the result */
puts(nuhash_tohex(digest, 0, hexstr));
}
```
Command-line Usage
==================
The **`nuhash`** command-line tool provides an interface similar to [`sha256sum`](https://linux.die.net/man/1/sha256sum) and friends:
```
Usage:
nuhash.exe [options] [<file_1> [... <file_n>]]
Options:
-b --binary Output digest as binary, default is hex-string.
-h --help Print the help screen and exit.
-i --ignore Ignore interrupt signals.
-l --line-mode Process the input file(s) as text, line by line.
-p --progress Print progress, while computing the hash.
-s --stop Stop on all errors, default is to keep going.
-t --self-test Run the built-in self-test.
-u --uppercase Print digest as uppercase, default is lowercase.
-v --version Print version information and exit.
```
### Example output:
```
abe9d2f9f55d62951540397875f1104d0374a7ce3ca9e21cfde6efd638b75765885f186477669b79d78d13b6d1abe0a2 foo
06573eaba880f77db3a9e6a085e3a4f8c1bf6f2997d6789bc38439d1f581e0907b21200aff43df37de27d241dc64d19e bar
e26b0338b7a3d662397cbc1ff9f81ac8885ee71f861f5897fc3a7b113ea314994f749caf7618a4bfc1ac90727ef64f94 baz
d113572666421a1e2cf6e17481f1f94b2b006e8c48504fea03e4b24d04930db4302368dc0e7bf44b104f7118bdd62f2d qux
```
Application Programming Interface (API)
=======================================
C99 API
-------
### Constants
The C99 API defines the following constants:
* **`NUHASH_WORDS`:** The size of the “raw” hash value (digest), in [`uint64_t`](https://cplusplus.com/reference/cstdint/) words.
* **`NUHASH_BYTES`:** The size of the “raw” hash value (digest), in bytes.
* **`NUHASH_CHARS`:** The size of the hash value (digest) encoded as a null-terminated “hex” string, in characters. This is twice the size of a “raw” hash value *plus* an additional slot for the terminating `\0` character.
### Simple
The ***simple*** API can be used to compute a hash value in an *“all at once”* fashion.
Use this API, if *all* input data is available at once. It can compute the hash value with as *single* function call.
#### `nuhash_compute()`
Compute the hash value from the given input data and return the resulting hash value (digest).
* Syntax:
```c
uint8_t *nuhash_compute(const uint8_t *const src, const size_t len, uint8_t *const out);
```
* Parameters:
- **`src`:** Pointer to the source array containing all input data to be processed (sequence of bytes).
- **`len`:** The length of the input data, in bytes.
- **`out`:** Pointer to the destination array where the hash value is stored, **must** be `NUHASH_BYTES` in size.
* Return value:
- This function returns the given `out` pointer.
#### `nuhash_compute_with_key()`
Compute the hash value from the given input data and a user-defined key; returns the hash value (digest).
* Syntax:
```c
uint8_t *nuhash_compute_with_key(const uint8_t *const key, const size_t key_len,
const uint8_t *const src, const size_t in_len, uint8_t *const out);
```
* Parameters:
- **`key`:** Pointer to the source array containing a user-defined key (sequence of bytes).
- **`key_len`:** The length of the user-defined key, in bytes.
- **`src`:** Pointer to the source array containing all input data to be processed (sequence of bytes).
- **`in_len`:** The length of the input data, in bytes.
- **`out`:** Pointer to the destination array where the hash value is stored, **must** be `NUHASH_BYTES` in size.
* Return value:
- This function returns the given `out` pointer.
### Stream API
The ***stream*** API can be used to compute a hash value in a *“step by step”* fashion.
Use this API, if **not** all input data is available at once. The input data can be processed in chunks of arbitrary size.
#### `nuhash_t`
An object containing the state of an ongoing hash computation.
The application **shall** treat this type as an *opaque* data structure; it is **not** meant to be accessed directly!
#### `nuhash_init()`
Initialize or reset the state for a new hash computation.
This function is supposed to be called exactly *once* at the beginning of a new hash computation!
* Syntax:
```c
void nuhash_init(nuhash_t *const ctx);
```
* Parameters:
- **`ctx`:** Pointer to the `nuhash_t` instance to be initialized.
#### `nuhash_init_with_key()`
Initialize or reset the state for a new hash computation with a user-defined key.
This function is supposed to be called exactly *once* at the beginning of a new hash computation!
* Syntax:
```c
void nuhash_init_with_key(nuhash_t *const ctx, const uint8_t *const key, const size_t len);
```
* Parameters:
- **`ctx`:** Pointer to the `nuhash_t` instance to be initialized.
- **`key`:** Pointer to the source array containing the user-defined key (sequence of bytes).
- **`len`:** The length of the user-defined key, in bytes.
#### `nuhash_update()`
Process the next chunk of input data and update the state.
This function is supposed to be called *repeatedly* until all the input data has been processed!
* Syntax:
```c
void nuhash_update(nuhash_t *const ctx, const uint8_t *const src, const size_t len);
```
* Parameters:
- **`ctx`:** Pointer to the `nuhash_t` instance to be updated.
- **`src`:** Pointer to the source array containing the next chunk of input data (sequence of bytes).
- **`len`:** The length of the input data, in bytes.
#### `nuhash_final()`
Finish the hash computation and return the resulting hash value (digest).
This function is supposed to be called exactly *once* after all the input data has been processed! After calling this function, the `nuhash_t` instance is **invalidated**; it must be [*reset*](#nuhash_init) in order to start a new hash computation.
* Syntax:
```c
uint8_t *nuhash_final(nuhash_t *const ctx, uint8_t *const out);
```
* Parameters:
- **`ctx`:** Pointer to the `nuhash_t` instance to be updated.
- **`out`:** Pointer to the destination array where the hash value is stored, **must** be `NUHASH_BYTES` in size.
* Return value:
- This function returns the given `out` pointer.
### Utilities
The C99 API also provides a few additional utility functions that may be helpful.
#### `nuhash_tohex()`
Converts a “raw” hash value (digest) into a null-terminated “hex” string.
* Syntax:
```c
char *nuhash_tohex(const uint8_t *const hash, const int upper, char *const out);
```
* Parameters:
- **`hash`:** Pointer to the source array containing the “raw” hash value, **must** be `NUHASH_BYTES` in size.
- **`upper`:** If non-zero, generate upper-case characters; otherwise generate lower-case characters.
- **`out`:** Pointer to the destination array where the “hex” string is stored, **must** be `NUHASH_CHARS` in size.
* Return value:
- This function returns the given `out` pointer.
#### `nuhash_version()`
Returns the version number and the build date of the current *libnuhash* library.
* Syntax:
```c
char *nuhash_version(uint16_t version[3U], char *const build);
```
* Parameters:
- **`version`:** Pointer to the destination array where the *major*, *minor* and *patch* version are stored.
- **`build`:** Pointer to the destination array where the build date is stored, **must** be 12 characters in size.
* Return value:
- This function returns the given `build` pointer.
### Thread-safety
All functions provided by ***libnuhash*** are *thread-safe* and *reentrant*, in the sense that there is **no** implicitly shared “global” state; the functions operate strictly on the given input parameters. Specifically, the functions of the “stream” API maintain **all** state of the hash computation within the given `nuhash_t` instance. This means that these functions are *thread-safe* and *reentrant* as long as each “concurrent” invocation uses its own separate `nuhash_t` instance; **no** synchronization is required in that case. However, *libnuhash* makes **no** attempt to coordinate the access to the *same* `nuhash_t` instance between concurrent threads. If the *same* `nuhash_t` instance needs to be accessed by *multiple* concurrent threads (which generally is **not** advised), then the application is responsible for *serializing* all access to that “shared” instance, e.g. by using a [*mutex*](https://pubs.opengroup.org/onlinepubs/009604499/functions/pthread_mutex_lock.html) lock! Reentrancy can **not** be achieved with a single “shared” `nuhash_t`.
Source Code
===========
The source code is available from these [Git](https://git-scm.com/) mirrors:
* `git clone https://github.com/lordmulder/NuHash.git` ([Browse](https://github.com/lordmulder/NuHash))
* `git clone https://bitbucket.org/muldersoft/nuhash.git` ([Browse](https://bitbucket.org/muldersoft/nuhash/))
* `git clone https://gitlab.com/lord_mulder/nuhash.git` ([Browse](https://gitlab.com/lord_mulder/nuhash))
* `git clone https://repo.or.cz/nuhash.git` ([Browse](https://repo.or.cz/nuhash.git))
* `git clone https://punkindrublic.mooo.com:3000/Muldersoft/NuHash.git` ([Browse](https://punkindrublic.mooo.com:3000/Muldersoft/NuHash))
License
=======
This work has been released under the **CC0 1.0 Universal** license.
For details, please refer to:
<https://creativecommons.org/publicdomain/zero/1.0/legalcode>
Acknowledgment
--------------
Licenses for third-party components used by NuHash:
* [**Hash icons**](https://www.flaticon.com/free-icons/hash)
Created by Vectors Market &ndash; Flaticon. Free for personal and commercial use with attribution.
&marker;