82 lines
2.2 KiB
Rust
82 lines
2.2 KiB
Rust
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use crate::PublicKey;
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use thiserror::Error;
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pub type PrivateKeyBytes = [u8; 32];
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pub trait PrivateKey: Sized {
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type PublicKey: PublicKey;
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type Err: std::error::Error;
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fn from_bytes(b: &PrivateKeyBytes) -> Self;
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fn to_bytes(&self) -> PrivateKeyBytes;
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fn is_zero_valid_public_key() -> bool {
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false
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}
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fn key() -> &'static str;
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fn public_key(&self) -> Self::PublicKey;
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/// Derive a child [`PrivateKey`] with given `PrivateKeyBytes`.
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///
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/// # Errors
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///
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/// An error may be returned if:
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/// * A nonzero `other` is provided.
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/// * An error specific to the given algorithm was encountered.
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fn derive_child(&self, other: &PrivateKeyBytes) -> Result<Self, Self::Err>;
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}
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#[derive(Clone, Debug, Error)]
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pub enum PrivateKeyError {
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#[error("The provided private key must be nonzero, but is not")]
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NonZero,
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#[error("Unable to convert point to key")]
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PointToKey(#[from] k256::elliptic_curve::Error),
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}
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#[cfg(feature = "secp256k1")]
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use k256::NonZeroScalar;
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#[cfg(feature = "secp256k1")]
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impl PrivateKey for k256::SecretKey {
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type Err = PrivateKeyError;
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type PublicKey = k256::PublicKey;
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fn key() -> &'static str {
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"Bitcoin seed"
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}
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fn from_bytes(b: &PrivateKeyBytes) -> Self {
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Self::from_slice(b).expect("Invalid private key bytes")
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}
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fn to_bytes(&self) -> PrivateKeyBytes {
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// Note: Safety assured by type returned from EncodedPoint
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self.to_bytes().into()
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}
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fn derive_child(&self, other: &PrivateKeyBytes) -> Result<Self, Self::Err> {
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if other.iter().all(|n| n == &0) {
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return Err(PrivateKeyError::NonZero);
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}
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let other = *other;
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// Checked: See above nonzero check
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let scalar = Option::<NonZeroScalar>::from(NonZeroScalar::from_repr(other.into()))
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.expect("Should have been able to get a NonZeroScalar");
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let derived_scalar = self.to_nonzero_scalar().as_ref() + scalar.as_ref();
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Ok(
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Option::<NonZeroScalar>::from(NonZeroScalar::new(derived_scalar))
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.map(Into::into)
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.expect("Should be able to make Key"),
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)
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}
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fn public_key(&self) -> Self::PublicKey {
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self.public_key()
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}
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}
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