md-5 0.11.0

MD5 hash function
Documentation 
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

use core::fmt;
use digest::{
    HashMarker, Output,
    array::Array,
    block_api::{
        AlgorithmName, Block, BlockSizeUser, Buffer, BufferKindUser, Eager, FixedOutputCore,
        OutputSizeUser, Reset, UpdateCore,
    },
    common::hazmat::{DeserializeStateError, SerializableState, SerializedState},
    typenum::{U16, U24, U64, Unsigned},
};

pub use crate::compress::compress;
use crate::consts;

const STATE_LEN: usize = 4;

/// Core MD5 hasher state.
#[derive(Clone)]
pub struct Md5Core {
    block_len: u64,
    state: [u32; STATE_LEN],
}

impl HashMarker for Md5Core {}

impl BlockSizeUser for Md5Core {
    type BlockSize = U64;
}

impl BufferKindUser for Md5Core {
    type BufferKind = Eager;
}

impl OutputSizeUser for Md5Core {
    type OutputSize = U16;
}

impl UpdateCore for Md5Core {
    #[inline]
    fn update_blocks(&mut self, blocks: &[Block<Self>]) {
        self.block_len = self.block_len.wrapping_add(blocks.len() as u64);
        let blocks = Array::cast_slice_to_core(blocks);
        compress(&mut self.state, blocks)
    }
}

impl FixedOutputCore for Md5Core {
    #[inline]
    fn finalize_fixed_core(&mut self, buffer: &mut Buffer<Self>, out: &mut Output<Self>) {
        let bit_len = self
            .block_len
            .wrapping_mul(Self::BlockSize::U64)
            .wrapping_add(buffer.get_pos() as u64)
            .wrapping_mul(8);
        let mut s = self.state;
        buffer.len64_padding_le(bit_len, |b| compress(&mut s, &[b.0]));
        for (chunk, v) in out.chunks_exact_mut(4).zip(s.iter()) {
            chunk.copy_from_slice(&v.to_le_bytes());
        }
    }
}

impl Default for Md5Core {
    #[inline]
    fn default() -> Self {
        Self {
            block_len: 0,
            state: consts::STATE_INIT,
        }
    }
}

impl Reset for Md5Core {
    #[inline]
    fn reset(&mut self) {
        *self = Default::default();
    }
}

impl AlgorithmName for Md5Core {
    fn write_alg_name(f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str("Md5")
    }
}

impl fmt::Debug for Md5Core {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str("Md5Core { ... }")
    }
}

impl Drop for Md5Core {
    fn drop(&mut self) {
        #[cfg(feature = "zeroize")]
        {
            use digest::zeroize::Zeroize;
            self.state.zeroize();
            self.block_len.zeroize();
        }
    }
}

#[cfg(feature = "zeroize")]
impl digest::zeroize::ZeroizeOnDrop for Md5Core {}

impl SerializableState for Md5Core {
    type SerializedStateSize = U24;

    fn serialize(&self) -> SerializedState<Self> {
        let mut serialized_state = SerializedState::<Self>::default();

        for (val, chunk) in self.state.iter().zip(serialized_state.chunks_exact_mut(4)) {
            chunk.copy_from_slice(&val.to_le_bytes());
        }

        serialized_state[16..].copy_from_slice(&self.block_len.to_le_bytes());
        serialized_state
    }

    fn deserialize(
        serialized_state: &SerializedState<Self>,
    ) -> Result<Self, DeserializeStateError> {
        let (serialized_state, serialized_block_len) = serialized_state.split::<U16>();

        let mut state = [0; STATE_LEN];
        for (val, chunk) in state.iter_mut().zip(serialized_state.chunks_exact(4)) {
            *val = u32::from_le_bytes(chunk.try_into().unwrap());
        }

        let block_len = u64::from_le_bytes(*serialized_block_len.as_ref());

        Ok(Self { state, block_len })
    }
}