1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162

//! Contains structs used for hashing.
//!
//! ## Note
//! **Do not** use this hasher for hashing password
//! or other sensitive data since this hash does not
//! use any salt, it is vulnerable to a rainbow table
//! attack.


#[cfg(feature = "b64")]
use crate::FromBase64Error;
#[cfg(feature = "b64")]
use std::fmt;

use std::ptr;
use std::convert::TryInto;
use std::mem::ManuallyDrop;

use blake2::{Blake2b, Digest};
use generic_array::{GenericArray, typenum::U64};

pub struct Hasher {
	inner: Blake2b
}

impl Hasher {
	pub fn new() -> Self {
		Self {
			inner: Blake2b::new()
		}
	}

	pub fn update(&mut self, data: impl AsRef<[u8]>) {
		self.inner.update(data);
	}

	pub fn finalize(self) -> Hash {
		let arr = self.inner.finalize();
		Hash {
			bytes: convert_generic_array(arr)
		}
	}

	pub fn hash(data: impl AsRef<[u8]>) -> Hash {
		let mut hasher = Hasher::new();
		hasher.update(data);
		hasher.finalize()
	}
}

fn convert_generic_array<T>(arr: GenericArray<T, U64>) -> [T; 64] {
	// safe because both have the same memory layout
	// and generic array does it
	unsafe {
		// see https://docs.rs/generic-array/0.14.4/src/generic_array/lib.rs.html#636
		let a = ManuallyDrop::new(arr);
		ptr::read(&*a as *const GenericArray<T, U64> as *const [T; 64])
	}
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Hash {
	bytes: [u8; 64]
}

impl Hash {
	pub const LEN: usize = 64;

	pub fn from_bytes(bytes: [u8; 64]) -> Self {
		Self { bytes }
	}

	/// ## Panics
	/// if the slice is not 64 bytes long.
	pub fn from_slice(slice: &[u8]) -> Self {
		Self::from_bytes(slice.try_into().unwrap())
	}

	pub fn try_from_slice(slice: &[u8]) -> Option<Self> {
		slice.try_into().ok()
			.map(Self::from_bytes)
	}

	pub fn to_bytes(&self) -> [u8; 64] {
		self.bytes
	}

	pub fn as_slice(&self) -> &[u8] {
		&self.bytes
	}

	#[cfg(feature = "b64")]
	pub fn from_b64<T: AsRef<[u8]>>(input: T) -> Result<Self, FromBase64Error> {
		let b = base64::decode_config(input, base64::URL_SAFE_NO_PAD)?;
		Self::try_from_slice(&b)
			.ok_or(FromBase64Error::LengthNot64Bytes)
	}

	#[cfg(feature = "b64")]
	pub fn to_b64(&self) -> String {
		// returns 86 str
		base64::encode_config(self.as_slice(), base64::URL_SAFE_NO_PAD)
	}
}

impl From<[u8; 64]> for Hash {
	fn from(bytes: [u8; 64]) -> Self {
		Self::from_bytes(bytes)
	}
}

// DISPLAY
#[cfg(feature = "b64")]
impl fmt::Display for Hash {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
		f.write_str(&self.to_b64())
	}
}

#[cfg(all(feature = "serde", feature = "b64"))]
impl_serde!(Hash, 86);

#[cfg(test)]
mod tests {

	use super::*;

	#[test]
	fn hash_something() {

		let bytes: Vec<u8> = (0..=255).collect();

		let hash = Hasher::hash(bytes);

		let hash_bytes = [
			30, 204, 137, 111, 52, 211, 249, 202,
			196, 132, 199, 63, 117, 246, 165, 251,
			88, 238, 103, 132, 190, 65, 179, 95,
			70, 6, 123, 156, 101, 198, 58, 103,
			148, 211, 215, 68, 17, 44, 101, 63,
			115, 221, 125, 235, 102, 102, 32, 76,
			90, 155, 250, 91, 70, 8, 31, 193,
			15, 219, 231, 136, 79, 165, 203, 248
		];
		assert_eq!(hash.to_bytes(), hash_bytes);

	}

	#[test]
	#[cfg(feature = "b64")]
	fn hash_b64() {

		let bytes: Vec<u8> = (0..=255).collect();

		let hash = Hasher::hash(bytes);

		assert_eq!(hash.to_b64(), "HsyJbzTT-crEhMc_dfal-1juZ4S-QbNfRgZ7nGXGOme\
			U09dEESxlP3PdfetmZiBMWpv6W0YIH8EP2-eIT6XL-A");

	}

}