blsful 3.1.0

BLS signature implementation according to the IETF spec on the BLS12-381 curve.
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
140
141
142
143
144
145
146
147
148
149
150

use crate::impls::inner_types::*;
use crate::*;

/// Represents a BLS signature for multiple signatures that signed different messages
#[derive(PartialEq, Eq, serde::Serialize, serde::Deserialize)]
pub enum MultiSignature<C: BlsSignatureImpl> {
    /// The basic signature scheme
    Basic(
        #[serde(serialize_with = "traits::signature::serialize::<C, _>")]
        #[serde(deserialize_with = "traits::signature::deserialize::<C, _>")]
        <C as Pairing>::Signature,
    ),
    /// The message augmentation signature scheme
    MessageAugmentation(
        #[serde(serialize_with = "traits::signature::serialize::<C, _>")]
        #[serde(deserialize_with = "traits::signature::deserialize::<C, _>")]
        <C as Pairing>::Signature,
    ),
    /// The proof of possession scheme
    ProofOfPossession(
        #[serde(serialize_with = "traits::signature::serialize::<C, _>")]
        #[serde(deserialize_with = "traits::signature::deserialize::<C, _>")]
        <C as Pairing>::Signature,
    ),
}

impl<C: BlsSignatureImpl> Default for MultiSignature<C> {
    fn default() -> Self {
        Self::ProofOfPossession(<C as Pairing>::Signature::default())
    }
}

impl<C: BlsSignatureImpl> Display for MultiSignature<C> {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        match self {
            Self::Basic(s) => write!(f, "Basic({})", s),
            Self::MessageAugmentation(s) => write!(f, "MessageAugmentation({})", s),
            Self::ProofOfPossession(s) => write!(f, "ProofOfPossession({})", s),
        }
    }
}

impl<C: BlsSignatureImpl> fmt::Debug for MultiSignature<C> {
    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
        match self {
            Self::Basic(s) => write!(f, "Basic({:?})", s),
            Self::MessageAugmentation(s) => write!(f, "MessageAugmentation({:?})", s),
            Self::ProofOfPossession(s) => write!(f, "ProofOfPossession({:?})", s),
        }
    }
}

impl<C: BlsSignatureImpl> Copy for MultiSignature<C> {}

impl<C: BlsSignatureImpl> Clone for MultiSignature<C> {
    fn clone(&self) -> Self {
        *self
    }
}

impl<C: BlsSignatureImpl> subtle::ConditionallySelectable for MultiSignature<C> {
    fn conditional_select(a: &Self, b: &Self, choice: Choice) -> Self {
        match (a, b) {
            (Self::Basic(a), Self::Basic(b)) => {
                Self::Basic(<C as Pairing>::Signature::conditional_select(a, b, choice))
            }
            (Self::MessageAugmentation(a), Self::MessageAugmentation(b)) => {
                Self::MessageAugmentation(<C as Pairing>::Signature::conditional_select(
                    a, b, choice,
                ))
            }
            (Self::ProofOfPossession(a), Self::ProofOfPossession(b)) => {
                Self::ProofOfPossession(<C as Pairing>::Signature::conditional_select(a, b, choice))
            }
            _ => panic!("Signature::conditional_select: mismatched variants"),
        }
    }
}

impl<C: BlsSignatureImpl> TryFrom<&[Signature<C>]> for MultiSignature<C> {
    type Error = BlsError;

    fn try_from(sigs: &[Signature<C>]) -> Result<Self, Self::Error> {
        if sigs.len() < 2 {
            return Err(BlsError::InvalidSignature);
        }
        let mut g = <C as Pairing>::Signature::identity();
        for s in &sigs[1..] {
            if !s.same_scheme(&sigs[0]) {
                return Err(BlsError::InvalidSignatureScheme);
            }
            let ss = match s {
                Signature::Basic(sig) => sig,
                Signature::MessageAugmentation(_) => {
                    return Err(BlsError::InvalidSignatureScheme);
                }
                Signature::ProofOfPossession(sig) => sig,
            };
            g += ss;
        }
        match sigs[0] {
            Signature::Basic(s) => Ok(Self::Basic(g + s)),
            Signature::MessageAugmentation(s) => Ok(Self::MessageAugmentation(g + s)),
            Signature::ProofOfPossession(s) => Ok(Self::ProofOfPossession(g + s)),
        }
    }
}

impl_from_derivatives_generic!(MultiSignature);

impl<C: BlsSignatureImpl> From<&MultiSignature<C>> for Vec<u8> {
    fn from(value: &MultiSignature<C>) -> Self {
        serde_bare::to_vec(value).unwrap()
    }
}

impl<C: BlsSignatureImpl> TryFrom<&[u8]> for MultiSignature<C> {
    type Error = BlsError;

    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
        serde_bare::from_slice(value).map_err(|_| BlsError::InvalidSignature)
    }
}

impl<C: BlsSignatureImpl> MultiSignature<C> {
    /// Verify the multi-signature using the multi-public key
    pub fn verify<B: AsRef<[u8]>>(&self, pk: MultiPublicKey<C>, msg: B) -> BlsResult<()> {
        match self {
            Self::Basic(sig) => <C as BlsSignatureBasic>::verify(pk.0, *sig, msg),
            Self::MessageAugmentation(sig) => {
                <C as BlsSignatureMessageAugmentation>::verify(pk.0, *sig, msg)
            }
            Self::ProofOfPossession(sig) => <C as BlsSignaturePop>::verify(pk.0, *sig, msg),
        }
    }

    /// Extract the inner raw representation
    pub fn as_raw_value(&self) -> &<C as Pairing>::Signature {
        match self {
            Self::Basic(s) => s,
            Self::MessageAugmentation(s) => s,
            Self::ProofOfPossession(s) => s,
        }
    }

    /// Accumulate multiple signatures into a single signature
    pub fn from_signatures<B: AsRef<[Signature<C>]>>(signatures: B) -> BlsResult<Self> {
        Self::try_from(signatures.as_ref())
    }
}