Update readme

Signed-off-by: Denis Varlakov <[email protected]>

README.md

@@ -1,10 +1,15 @@
-Cryptographically-secure pseudo-random generator based on cryptographic hash function
+![License](https://img.shields.io/crates/l/rand_hash.svg)
+[![Docs](https://docs.rs/rand_hash/badge.svg)](https://docs.rs/rand_hash)
+[![Crates io](https://img.shields.io/crates/v/rand_hash.svg)](https://crates.io/crates/rand_hash)
+[![Discord](https://img.shields.io/discord/905194001349627914?logo=discord&logoColor=ffffff&label=Discord)][in Discord]
+
+# Cryptographically-secure pseudo-random generator based on cryptographic hash function
 
 `HashRng` is CSPRNG that takes any hashable data as seed and produces a stream
-of randomness that has the same entropy as the seed. It uses `udigest` crate to
+of randomness that has the same entropy as the seed. It uses [`udigest`](https://docs.rs/udigest) crate to
 unambiguously hash the seed.
 
-### Motivation
+## Motivation
 Usually, CSPRNGs have a fixed-size seed. For instance, [`ChaCha20Rng`](https://docs.rs/rand_chacha/latest/rand_chacha/struct.ChaCha20Rng.html)
 has seed of 32 bytes. That means that when you want to derive randomness from data which
 has entropy exceeding 32 bytes, you'll have to truncate the seed to 32 bytes (e.g. by hashing it),
@@ -14,24 +19,24 @@ parameter and make it less secure than desired.
 `HashRng`, on other hand, takes advantage of full entropy of the seed. It does so by
 hashing a counter and then the seed for each block, i.e. the output randomness is:
 
-```
+```text
 HashRng(seed) = H(0, seed) || H(1, seed) || ...
 ```
 
-### Security and performance considerations
+## Security and performance considerations
 `HashRng` internally uses u64 counter, which means that the period of the sequence is
 2<sup>64</sup> times `Digest::OutputSize` (size of hash output).
 
 Although we did not perform benchmarks, intuitively, `HashRng` is expected to be noticeably
 slower than other CSPRNG based on permutations (such as `ChaCha20Rng`)
 
-### Example
+## Example
 ```rust
 use rand::RngCore;
 
 #[derive(udigest::Digestable)]
 pub struct Seed<'a> {
-    nonce: &'a u8,
+    nonce: &'a [u8],
     param_a: &'a str,
     param_b: &'a str,
     // ...
@@ -45,6 +50,11 @@ let seed = Seed {
 };
 let mut rng = rand_hash::HashRng::<sha2::Sha256, _>::from_seed(&seed);
 
-let mut randomness = 0u8; 256;
+let mut randomness = [0u8; 256];
 rng.fill_bytes(&mut randomness);
 ```
+
+## Join us in Discord!
+Feel free to reach out to us [in Discord]!
+
+[in Discord]: https://discordapp.com/channels/905194001349627914/1285268686147424388

src/lib.rs

@@ -1,54 +1,4 @@
-//! Cryptographically-secure pseudo-random generator based on cryptographic hash function
-//!
-//! [`HashRng`] is CSPRNG that takes any hashable data as seed and produces a stream
-//! of randomness that has the same entropy as the seed. It uses [`udigest`] crate to
-//! unambiguously hash the seed.
-//!
-//! ## Motivation
-//! Usually, CSPRNGs have a fixed-size seed. For instance, [`ChaCha20Rng`](https://docs.rs/rand_chacha/latest/rand_chacha/struct.ChaCha20Rng.html)
-//! has seed of 32 bytes. That means that when you want to derive randomness from data which
-//! has entropy exceeding 32 bytes, you'll have to truncate the seed to 32 bytes (e.g. by hashing it),
-//! so you won't be able to take advantage of exceeding entropy. This may influence security
-//! parameter and make it less secure than desired.
-//!
-//! [`HashRng`], on other hand, takes advantage of full entropy of the seed. It does so by
-//! hashing a counter and then the seed for each block, i.e. the output randomness is:
-//!
-//! ```text
-//! HashRng(seed) = H(0, seed) || H(1, seed) || ...
-//! ```
-//!
-//! ## Security and performance considerations
-//! `HashRng` internally uses u64 counter, which means that the period of the sequence is
-//! 2<sup>64</sup> times `Digest::OutputSize` (size of hash output).
-//!
-//! Although we did not perform benchmarks, intuitively, `HashRng` is expected to be noticeably
-//! slower than other CSPRNG based on permutations (such as `ChaCha20Rng`)
-//!
-//! ## Example
-//! ```rust
-//! use rand::RngCore;
-//!
-//! #[derive(udigest::Digestable)]
-//! pub struct Seed<'a> {
-//!     nonce: &'a [u8],
-//!     param_a: &'a str,
-//!     param_b: &'a str,
-//!     // ...
-//! }
-//!
-//! let seed = Seed {
-//!     nonce: b"very unpredictable string",
-//!     param_a: "some other data containing entropy",
-//!     param_b: "something else",
-//!     // ...
-//! };
-//! let mut rng = rand_hash::HashRng::<sha2::Sha256, _>::from_seed(&seed);
-//!
-//! let mut randomness = [0u8; 256];
-//! rng.fill_bytes(&mut randomness);
-//! ```
-
+#![doc = include_str!("../README.md")]
 #![no_std]
 #![forbid(unused_crate_dependencies, missing_docs)]
 #![cfg_attr(