Struct PublicKey

pub struct PublicKey(/* private fields */);

Public key - used to verify ECDSA signatures and to do Taproot tweaks.

Serde support

Implements de/serialization with the serde feature enabled. We treat the byte value as a tuple of 33 u8s for non-human-readable formats. This representation is optimal for for some formats (e.g. bincode) however other formats may be less optimal (e.g. cbor).

Examples

Basic usage:

use secp256k1::{SecretKey, Secp256k1, PublicKey};

let secp = Secp256k1::new();
let secret_key = SecretKey::from_byte_array(&[0xcd; 32]).expect("32 bytes, within curve order");
let public_key = PublicKey::from_secret_key(&secp, &secret_key);

Implementations

impl PublicKey

pub fn cmp_fast_unstable(&self, other: &Self) -> Ordering

Like cmp::Cmp but faster and with no guarantees across library versions.

The Cmp implementation for FFI types is stable but slow because it first serializes self and other before comparing them. This function provides a faster comparison if you know that your types come from the same library version.

pub fn eq_fast_unstable(&self, other: &Self) -> bool

Like cmp::Eq but faster and with no guarantees across library versions.

The Eq implementation for FFI types is stable but slow because it first serializes self and other before comparing them. This function provides a faster equality check if you know that your types come from the same library version.

impl PublicKey

pub fn as_ptr(&self) -> *const PublicKey

👎Deprecated since 0.25.0: Use Self::as_c_ptr if you need to access the FFI layer

Obtains a raw const pointer suitable for use with FFI functions.

pub fn as_mut_ptr(&mut self) -> *mut PublicKey

👎Deprecated since 0.25.0: Use Self::as_mut_c_ptr if you need to access the FFI layer

Obtains a raw mutable pointer suitable for use with FFI functions.

pub fn from_secret_key<C: Signing>( secp: &Secp256k1<C>, sk: &SecretKey, ) -> PublicKey

Creates a new public key from a SecretKey.

Examples

use secp256k1::{rand, Secp256k1, SecretKey, PublicKey};

let secp = Secp256k1::new();
let secret_key = SecretKey::new(&mut rand::thread_rng());
let public_key = PublicKey::from_secret_key(&secp, &secret_key);

pub fn from_ellswift(ellswift: ElligatorSwift) -> PublicKey

Creates a new public key from an ElligatorSwift.

pub fn from_secret_key_global(sk: &SecretKey) -> PublicKey

Available on crate feature global-context only.

Creates a new public key from a SecretKey and the global SECP256K1 context.

pub fn from_slice(data: &[u8]) -> Result<PublicKey, Error>

Creates a public key directly from a slice.

pub fn from_byte_array_compressed(data: &[u8; 33]) -> Result<PublicKey, Error>

Creates a public key from a serialized array in compressed format.

pub fn from_byte_array_uncompressed(data: &[u8; 65]) -> Result<PublicKey, Error>

Creates a public key from a serialized array in uncompressed format.

pub fn from_keypair(keypair: &Keypair) -> Self

Creates a new compressed public key using data from BIP-340 Keypair.

Examples

use secp256k1::{rand, Secp256k1, PublicKey, Keypair};

let secp = Secp256k1::new();
let keypair = Keypair::new(&secp, &mut rand::thread_rng());
let public_key = PublicKey::from_keypair(&keypair);

pub fn from_x_only_public_key(pk: XOnlyPublicKey, parity: Parity) -> PublicKey

Creates a PublicKey using the key material from pk combined with the parity.

pub fn serialize(&self) -> [u8; 33]

Serializes the key as a byte-encoded pair of values. In compressed form the y-coordinate is represented by only a single bit, as x determines it up to one bit.

pub fn serialize_uncompressed(&self) -> [u8; 65]

Serializes the key as a byte-encoded pair of values, in uncompressed form.

pub fn negate<C: Verification>(self, secp: &Secp256k1<C>) -> PublicKey

Negates the public key.

pub fn add_exp_tweak<C: Verification>( self, secp: &Secp256k1<C>, tweak: &Scalar, ) -> Result<PublicKey, Error>

Tweaks a PublicKey by adding tweak * G modulo the curve order.

Errors

Returns an error if the resulting key would be invalid.

pub fn mul_tweak<C: Verification>( self, secp: &Secp256k1<C>, other: &Scalar, ) -> Result<PublicKey, Error>

Tweaks a PublicKey by multiplying by tweak modulo the curve order.

Errors

Returns an error if the resulting key would be invalid.

pub fn combine(&self, other: &PublicKey) -> Result<PublicKey, Error>

Adds a second key to this one, returning the sum.

Errors

If the result would be the point at infinity, i.e. adding this point to its own negation.

Examples

use secp256k1::{rand, Secp256k1};

let secp = Secp256k1::new();
let mut rng = rand::thread_rng();
let (_, pk1) = secp.generate_keypair(&mut rng);
let (_, pk2) = secp.generate_keypair(&mut rng);
let sum = pk1.combine(&pk2).expect("It's improbable to fail for 2 random public keys");

pub fn combine_keys(keys: &[&PublicKey]) -> Result<PublicKey, Error>

Adds the keys in the provided slice together, returning the sum.

Errors

Errors under any of the following conditions:

• The result would be the point at infinity, i.e. adding a point to its own negation.
• The provided slice is empty.
• The number of elements in the provided slice is greater than i32::MAX.

Examples

use secp256k1::{rand, Secp256k1, PublicKey};

let secp = Secp256k1::new();
let mut rng = rand::thread_rng();
let (_, pk1) = secp.generate_keypair(&mut rng);
let (_, pk2) = secp.generate_keypair(&mut rng);
let (_, pk3) = secp.generate_keypair(&mut rng);
let sum = PublicKey::combine_keys(&[&pk1, &pk2, &pk3]).expect("It's improbable to fail for 3 random public keys");

pub fn x_only_public_key(&self) -> (XOnlyPublicKey, Parity)

Returns the XOnlyPublicKey (and it’s Parity) for this PublicKey.

pub fn verify<C: Verification>( &self, secp: &Secp256k1<C>, msg: &Message, sig: &Signature, ) -> Result<(), Error>

Checks that sig is a valid ECDSA signature for msg using this public key.

Trait Implementations

impl CPtr for PublicKey

This trait enables interaction with the FFI layer and even though it is part of the public API normal users should never need to directly interact with FFI types.

fn as_c_ptr(&self) -> *const Self::Target

Obtains a const pointer suitable for use with FFI functions.

fn as_mut_c_ptr(&mut self) -> *mut Self::Target

Obtains a mutable pointer suitable for use with FFI functions.

type Target = PublicKey

impl Clone for PublicKey

fn clone(&self) -> PublicKey

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PublicKey

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for PublicKey

Available on crate feature serde only.

fn deserialize<D: Deserializer<'de>>(d: D) -> Result<PublicKey, D::Error>

Deserialize this value from the given Serde deserializer.

impl Display for PublicKey

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'a> From<&'a Keypair> for PublicKey

fn from(pair: &'a Keypair) -> Self

Converts to this type from the input type.

impl From<Keypair> for PublicKey

fn from(pair: Keypair) -> Self

Converts to this type from the input type.

impl From<PublicKey> for PublicKey

Creates a new public key from a FFI public key.

Note, normal users should never need to interact directly with FFI types.

fn from(pk: PublicKey) -> PublicKey

Converts to this type from the input type.

impl From<PublicKey> for XOnlyPublicKey

fn from(src: PublicKey) -> XOnlyPublicKey

Converts to this type from the input type.

impl FromStr for PublicKey

type Err = Error

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<PublicKey, Error>

Parses a string s to return a value of this type.

impl Hash for PublicKey

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl LowerHex for PublicKey

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Ord for PublicKey

fn cmp(&self, other: &PublicKey) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for PublicKey

fn eq(&self, other: &PublicKey) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for PublicKey

fn partial_cmp(&self, other: &PublicKey) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for PublicKey

Available on crate feature serde only.

fn serialize<S: Serializer>(&self, s: S) -> Result<S::Ok, S::Error>

Serialize this value into the given Serde serializer.

impl Copy for PublicKey

impl Eq for PublicKey

impl StructuralPartialEq for PublicKey