sad-rsa 0.2.0

Hardened pure Rust RSA implementation with Marvin attack mitigation
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
136
137
138
139

use super::decrypt_digest;
use crate::{
    dummy_rng::DummyRng,
    traits::{Decryptor, RandomizedDecryptor},
    Result, RsaPrivateKey,
};
use alloc::{boxed::Box, vec::Vec};
use core::marker::PhantomData;
use digest::{Digest, FixedOutputReset};
use rand_core::CryptoRng;
#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};
use zeroize::ZeroizeOnDrop;

/// Decryption key for PKCS#1 v1.5 decryption as described in [RFC8017 § 7.1].
///
/// [RFC8017 § 7.1]: https://datatracker.ietf.org/doc/html/rfc8017#section-7.1
#[derive(Debug, Clone)]
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
pub struct DecryptingKey<D, MGD = D>
where
    D: Digest,
    MGD: Digest + FixedOutputReset,
{
    inner: RsaPrivateKey,
    label: Option<Box<[u8]>>,
    phantom: PhantomData<D>,
    mg_phantom: PhantomData<MGD>,
}

impl<D, MGD> DecryptingKey<D, MGD>
where
    D: Digest,
    MGD: Digest + FixedOutputReset,
{
    /// Create a new verifying key from an RSA public key.
    pub fn new(key: RsaPrivateKey) -> Self {
        Self {
            inner: key,
            label: None,
            phantom: Default::default(),
            mg_phantom: Default::default(),
        }
    }

    /// Create a new verifying key from an RSA public key using provided label
    pub fn new_with_label<S: Into<Box<[u8]>>>(key: RsaPrivateKey, label: S) -> Self {
        Self {
            inner: key,
            label: Some(label.into()),
            phantom: Default::default(),
            mg_phantom: Default::default(),
        }
    }
}

impl<D, MGD> Decryptor for DecryptingKey<D, MGD>
where
    D: Digest,
    MGD: Digest + FixedOutputReset,
{
    fn decrypt(&self, ciphertext: &[u8]) -> Result<Vec<u8>> {
        decrypt_digest::<DummyRng, D, MGD>(None, &self.inner, ciphertext, self.label.clone())
    }
}

impl<D, MGD> RandomizedDecryptor for DecryptingKey<D, MGD>
where
    D: Digest,
    MGD: Digest + FixedOutputReset,
{
    fn decrypt_with_rng<R: CryptoRng + ?Sized>(
        &self,
        rng: &mut R,
        ciphertext: &[u8],
    ) -> Result<Vec<u8>> {
        decrypt_digest::<_, D, MGD>(Some(rng), &self.inner, ciphertext, self.label.clone())
    }
}

impl<D, MGD> ZeroizeOnDrop for DecryptingKey<D, MGD>
where
    D: Digest,
    MGD: Digest + FixedOutputReset,
{
}

impl<D, MGD> PartialEq for DecryptingKey<D, MGD>
where
    D: Digest,
    MGD: Digest + FixedOutputReset,
{
    fn eq(&self, other: &Self) -> bool {
        self.inner == other.inner && self.label == other.label
    }
}

#[cfg(test)]
mod tests {
    #[test]
    #[cfg(all(feature = "hazmat", feature = "serde"))]
    fn test_serde() {
        use super::*;
        use rand::rngs::ChaCha8Rng;
        use rand_core::SeedableRng;
        use serde_test::{assert_tokens, Configure, Token};
        use sha2::Sha256;

        let mut rng = ChaCha8Rng::from_seed([42; 32]);
        let decrypting_key = DecryptingKey::<Sha256>::new(
            RsaPrivateKey::new_unchecked(&mut rng, 64).expect("failed to generate key"),
        );

        let tokens = [
            Token::Struct {
                name: "DecryptingKey",
                len: 4,
            },
            Token::Str("inner"),
            Token::Str(concat!(
                "3056020100300d06092a864886f70d010101050004423040020100020900ab",
                "240c3361d02e370203010001020811e54a15259d22f9020500ceff5cf30205",
                "00d3a7aaad020500ccaddf17020500cb529d3d020500bb526d6f"
            )),
            Token::Str("label"),
            Token::None,
            Token::Str("phantom"),
            Token::UnitStruct {
                name: "PhantomData",
            },
            Token::Str("mg_phantom"),
            Token::UnitStruct {
                name: "PhantomData",
            },
            Token::StructEnd,
        ];
        assert_tokens(&decrypting_key.readable(), &tokens);
    }
}