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

//! An implementation of the SHA-1 cryptographic hash algorithm.

//! To use this module, first create a `Sha1` object using the `Sha1` constructor,
//! then feed it an input message using the `input` or `input_str` methods,
//! which may be called any number of times; they will buffer the input until
//! there is enough to call the block algorithm.
//!
//! After the entire input has been fed to the hash read the result using
//! the `result` or `result_str` methods. The first will return bytes, and
//! the second will return a `String` object of the same bytes represented
//! in hexadecimal form.
//!
//! The `Sha1` object may be reused to create multiple hashes by calling
//! the `reset()` method. These traits are implemented by all hash digest
//! algorithms that implement the `Digest` trait. An example of use is:
//!
//! ```rust
//! use sha_1::{Sha1, Digest};
//!
//! // create a Sha1 object
//! let mut sh = Sha1::default();
//!
//! // write input message
//! sh.input(b"hello world");
//!
//! // read hash digest in the form of GenericArray which is in this case
//! // equivalent to [u8; 20]
//! let output = sh.result();
//! assert_eq!(output[..], [0x2a, 0xae, 0x6c, 0x35, 0xc9, 0x4f, 0xcf, 0xb4, 0x15, 0xdb,
//!                         0xe9, 0x5f, 0x40, 0x8b, 0x9c, 0xe9, 0x1e, 0xe8, 0x46, 0xed]);
//! ```
//!
//! # Mathematics
//!
//! The mathematics of the SHA-1 algorithm are quite interesting. In its
//! definition, The SHA-1 algorithm uses:
//!
//! * 1 binary operation on bit-arrays:
//!   * "exclusive or" (XOR)
//! * 2 binary operations on integers:
//!   * "addition" (ADD)
//!   * "rotate left" (ROL)
//! * 3 ternary operations on bit-arrays:
//!   * "choose" (CH)
//!   * "parity" (PAR)
//!   * "majority" (MAJ)
//!
//! Some of these functions are commonly found in all hash digest
//! algorithms, but some, like "parity" is only found in SHA-1.
#![no_std]
extern crate block_buffer;
extern crate byte_tools;
#[cfg(feature = "generic")]
extern crate digest;
#[cfg(feature = "generic")]
extern crate generic_array;


#[cfg(not(feature = "asm"))]
extern crate fake_simd as simd;

#[cfg(feature = "asm")]
extern crate sha1_asm as utils;
#[cfg(not(feature = "asm"))]
mod utils;

use utils::compress;

use byte_tools::write_u32v_be;
use block_buffer::BlockBuffer512;

#[cfg(feature = "generic")]
pub use digest::Digest;
#[cfg(feature = "generic")]
use generic_array::GenericArray;
#[cfg(feature = "generic")]
use generic_array::typenum::{U20, U64};

mod consts;
use consts::{STATE_LEN, H};

/// Structure representing the state of a SHA-1 computation
#[derive(Copy, Clone)]
pub struct Sha1 {
    h: [u32; STATE_LEN],
    len: u64,
    buffer: BlockBuffer512,
}

impl Default for Sha1 {
    fn default() -> Self {
        Sha1{ h: H, len: 0u64, buffer: Default::default() }
    }
}

impl Sha1 {
    #[inline]
    fn finalize(mut self) -> [u32; STATE_LEN] {
        {
            let state = &mut self.h;
            let len_bits = self.len << 3;
            self.buffer.len_padding(len_bits.to_be(), |d| compress(state, d));
        }
        self.h
    }

    #[inline]
    pub fn hash(self) -> [u8; 20] {
        let mut out = [0u8; 20];
        write_u32v_be(&mut out, &self.finalize());
        out
    }

    #[inline]
    pub fn consume(&mut self, input: &[u8]) {
        // Assumes that `length_bits<<3` will not overflow
        self.len += input.len() as u64;
        let state = &mut self.h;
        self.buffer.input(input, |d| compress(state, d));
    }
}

#[cfg(feature = "generic")]
impl digest::BlockInput for Sha1 {
    type BlockSize = U64;
}

#[cfg(feature = "generic")]
impl digest::Input for Sha1 {
    fn process(&mut self, input: &[u8]) {
        self.consume(input);
    }
}

#[cfg(feature = "generic")]
impl digest::FixedOutput for Sha1 {
    type OutputSize = U20;

    fn fixed_result(self) -> GenericArray<u8, Self::OutputSize> {
        let mut out = GenericArray::default();
        write_u32v_be(&mut out, &self.finalize());
        out
    }
}