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

//! # Verifiable Random Function
//!
//! This crate defines a trait that must be implemented by VRFs.
//!
use openssl::{
    rsa::Rsa,
    pkey::{Public, Private}
};

pub mod vrf;

/// A trait containing the common capabilities for VRF implementations
///
pub trait VRF {
    type Error;

    /// Generates proof from a private key and a message
    ///
    /// # Arguments:
    ///
    /// *    `pkey`: a private key
    /// *    `alpha_string`: octet string message represented by a slice
    ///
    /// # Returns:
    ///
    /// *    if successful, a vector of octets representing the VRF proof
    ///
    fn prove(&mut self, pkey: &Rsa<Private>, alpha_string: &[u8]) -> Result<Vec<u8>, Self::Error>;

    /// Generates VRF hash output from the provided proof
    ///
    /// # Arguments:
    ///
    /// *    `pi_string`: generated VRF proof
    ///
    /// # Returns:
    ///
    /// *    the VRF hash output
    ///
    fn proof_to_hash(&mut self, pi_string: &[u8]) -> Result<Vec<u8>, Self::Error>;

    /// Verifies the provided VRF proof and computes the VRF hash output
    ///
    /// # Arguments:
    ///
    /// *    `public_key`: a public key
    /// *    `alpha_string`: VRF hash input, an octet string
    /// *    `pi_string`: proof to be verified, an octet string
    /// 
    /// # Returns:
    ///
    /// *    if successful, a vector of octets with the VRF hash output
    ///
    fn verify(&mut self, public_key: &Rsa<Public>, alpha_string: &[u8], pi_string: &[u8]) -> Result<Vec<u8>, Self::Error>;
}

pub mod ecvrf;

/// A trait containing common capabilities for ECVRF implementations
///
pub trait ECVRF<PrivateKey, PublicKey> {
    type Error;

    /// Generates proof from a private key and a message
    ///
    /// # Arguments:
    ///
    /// *    `pkey`: a private key
    /// *    `alpha_string`: octet string message represented by a slice
    ///
    /// # Returns:
    ///
    /// *    if successful, a vector of octets representing the VRF proof
    ///
    fn prove(&mut self, pkey: PrivateKey, alpha_string: &[u8]) -> Result<Vec<u8>, Self::Error>;

    /// Generates VRF hash output from the provided proof
    ///
    /// # Arguments:
    ///
    /// *    `pi_string`: generated VRF proof
    ///
    /// # Returns:
    ///
    /// *    the VRF hash output
    ///
    fn proof_to_hash(&mut self, pi_string: &[u8]) -> Result<Vec<u8>, Self::Error>;

    /// Verifies the provided VRF proof and computes the VRF hash output
    ///
    /// # Arguments:
    ///
    /// *    `public_key`: a public key
    /// *    `alpha_string`: VRF hash input, an octet string
    /// *    `pi_string`: proof to be verified, an octet string
    /// 
    /// # Returns:
    ///
    /// *    if successful, a vector of octets with the VRF hash output
    ///
    fn verify(&mut self, public_key: PublicKey, alpha_string: &[u8], pi_string: &[u8]) -> Result<Vec<u8>, Self::Error>;
}