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
151
152
153

#![no_std]
#![cfg_attr(docsrs, feature(doc_auto_cfg))]
#![doc = include_str!("../README.md")]
#![doc(
    html_logo_url = "https://raw.githubusercontent.com/RustCrypto/meta/master/logo.svg",
    html_favicon_url = "https://raw.githubusercontent.com/RustCrypto/meta/master/logo.svg"
)]
#![forbid(unsafe_code)]
#![warn(
    clippy::mod_module_files,
    clippy::unwrap_used,
    missing_docs,
    rust_2018_idioms,
    unused_lifetimes,
    unused_qualifications
)]

//! ## `serde` support
//!
//! When the `serde` feature of this crate is enabled, `Serialize` and
//! `Deserialize` are impl'd for the following types:
//!
//! - [`AffinePoint`]
//! - [`Scalar`]
//! - [`ecdsa::VerifyingKey`]
//!
//! Please see type-specific documentation for more information.

#[cfg(feature = "arithmetic")]
mod arithmetic;

#[cfg(feature = "ecdh")]
pub mod ecdh;

#[cfg(feature = "ecdsa-core")]
pub mod ecdsa;

#[cfg(feature = "schnorr")]
pub mod schnorr;

#[cfg(any(feature = "test-vectors", test))]
pub mod test_vectors;

pub use elliptic_curve::{self, bigint::U256};

#[cfg(feature = "arithmetic")]
pub use arithmetic::{affine::AffinePoint, projective::ProjectivePoint, scalar::Scalar};

#[cfg(feature = "expose-field")]
pub use arithmetic::FieldElement;

#[cfg(feature = "pkcs8")]
pub use elliptic_curve::pkcs8;

#[cfg(feature = "sha2")]
pub use sha2;

use elliptic_curve::{
    bigint::ArrayEncoding,
    consts::{U32, U33, U64},
    generic_array::GenericArray,
    FieldBytesEncoding,
};

/// Order of the secp256k1 elliptic curve in hexadecimal.
const ORDER_HEX: &str = "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141";

/// Order of the secp256k1 elliptic curve.
const ORDER: U256 = U256::from_be_hex(ORDER_HEX);

/// secp256k1 (K-256) elliptic curve.
///
/// Specified in Certicom's SECG in "SEC 2: Recommended Elliptic Curve Domain Parameters":
///
/// <https://www.secg.org/sec2-v2.pdf>
///
/// The curve's equation is `y² = x³ + 7` over a ~256-bit prime field.
///
/// It's primarily notable for usage in Bitcoin and other cryptocurrencies,
/// particularly in conjunction with the Elliptic Curve Digital Signature
/// Algorithm (ECDSA).
#[derive(Copy, Clone, Debug, Default, Eq, PartialEq, PartialOrd, Ord)]
pub struct Secp256k1;

impl elliptic_curve::Curve for Secp256k1 {
    /// 32-byte serialized field elements.
    type FieldBytesSize = U32;

    /// 256-bit field modulus.
    type Uint = U256;

    /// Curve order.
    const ORDER: U256 = ORDER;
}

impl elliptic_curve::PrimeCurve for Secp256k1 {}

impl elliptic_curve::point::PointCompression for Secp256k1 {
    /// secp256k1 points are typically compressed.
    const COMPRESS_POINTS: bool = true;
}

#[cfg(feature = "jwk")]
impl elliptic_curve::JwkParameters for Secp256k1 {
    const CRV: &'static str = "secp256k1";
}

#[cfg(feature = "pkcs8")]
impl pkcs8::AssociatedOid for Secp256k1 {
    const OID: pkcs8::ObjectIdentifier = pkcs8::ObjectIdentifier::new_unwrap("1.3.132.0.10");
}

/// Compressed SEC1-encoded secp256k1 (K-256) curve point.
pub type CompressedPoint = GenericArray<u8, U33>;

/// SEC1-encoded secp256k1 (K-256) curve point.
pub type EncodedPoint = elliptic_curve::sec1::EncodedPoint<Secp256k1>;

/// secp256k1 (K-256) field element serialized as bytes.
///
/// Byte array containing a serialized field element value (base field or scalar).
pub type FieldBytes = elliptic_curve::FieldBytes<Secp256k1>;

impl FieldBytesEncoding<Secp256k1> for U256 {
    fn decode_field_bytes(field_bytes: &FieldBytes) -> Self {
        U256::from_be_byte_array(*field_bytes)
    }

    fn encode_field_bytes(&self) -> FieldBytes {
        self.to_be_byte_array()
    }
}

/// Bytes used by a wide reduction: twice the width of [`FieldBytes`].
pub type WideBytes = GenericArray<u8, U64>;

/// Non-zero secp256k1 (K-256) scalar field element.
#[cfg(feature = "arithmetic")]
pub type NonZeroScalar = elliptic_curve::NonZeroScalar<Secp256k1>;

/// secp256k1 (K-256) public key.
#[cfg(feature = "arithmetic")]
pub type PublicKey = elliptic_curve::PublicKey<Secp256k1>;

/// secp256k1 (K-256) secret key.
pub type SecretKey = elliptic_curve::SecretKey<Secp256k1>;

#[cfg(not(feature = "arithmetic"))]
impl elliptic_curve::sec1::ValidatePublicKey for Secp256k1 {}

/// Bit representation of a secp256k1 (K-256) scalar field element.
#[cfg(feature = "bits")]
pub type ScalarBits = elliptic_curve::scalar::ScalarBits<Secp256k1>;