Struct Signature

pub struct Signature<C: PrimeCurve> { /* private fields */ }

ECDSA signature (fixed-size). Generic over elliptic curve types.

Serialized as fixed-sized big endian scalar values with no added framing:

• r: field element size for the given curve, big-endian
• s: field element size for the given curve, big-endian

Both r and s MUST be non-zero.

For example, in a curve with a 256-bit modulus like NIST P-256 or secp256k1, r and s will both be 32-bytes and serialized as big endian, resulting in a signature with a total of 64-bytes.

ASN.1 DER-encoded signatures also supported via the Signature::from_der and Signature::to_der methods.

serde support

When the serde feature of this crate is enabled, it provides support for serializing and deserializing ECDSA signatures using the Serialize and Deserialize traits.

The serialization uses a hexadecimal encoding when used with “human readable” text formats, and a binary encoding otherwise.

Implementations

impl<C> Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

pub fn from_bytes(bytes: &SignatureBytes<C>) -> Result<Self>

Parse a signature from fixed-width bytes, i.e. 2 * the size of FieldBytes for a particular curve.

Returns

• Ok(signature) if the r and s components are both in the valid range 1..n when serialized as concatenated big endian integers.
• Err(err) if the r and/or s component of the signature is out-of-range when interpreted as a big endian integer.

pub fn from_slice(slice: &[u8]) -> Result<Self>

Parse a signature from a byte slice.

pub fn from_der(bytes: &[u8]) -> Result<Self>

where MaxSize<C>: ArrayLength<u8>, <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArrayLength<u8>,

Parse a signature from ASN.1 DER.

pub fn from_scalars( r: impl Into<FieldBytes<C>>, s: impl Into<FieldBytes<C>>, ) -> Result<Self>

Create a Signature from the serialized r and s scalar values which comprise the signature.

Returns

• Ok(signature) if the r and s components are both in the valid range 1..n when serialized as concatenated big endian integers.
• Err(err) if the r and/or s component of the signature is out-of-range when interpreted as a big endian integer.

pub fn split_bytes(&self) -> (FieldBytes<C>, FieldBytes<C>)

Split the signature into its r and s components, represented as bytes.

pub fn to_bytes(&self) -> SignatureBytes<C>

Serialize this signature as bytes.

pub fn to_der(&self) -> Signature<C>

where MaxSize<C>: ArrayLength<u8>, <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArrayLength<u8>,

Serialize this signature as ASN.1 DER.

pub fn to_vec(&self) -> Vec<u8>

Convert this signature into a byte vector.

impl<C> Signature<C>

where C: PrimeCurve + CurveArithmetic, SignatureSize<C>: ArrayLength<u8>,

pub fn r(&self) -> NonZeroScalar<C>

Get the r component of this signature

pub fn s(&self) -> NonZeroScalar<C>

Get the s component of this signature

pub fn split_scalars(&self) -> (NonZeroScalar<C>, NonZeroScalar<C>)

Split the signature into its r and s scalars.

pub fn normalize_s(&self) -> Option<Self>

Normalize signature into “low S” form as described in BIP 0062: Dealing with Malleability.

Trait Implementations

impl<C> AssociatedOid for Signature<C>

where C: DigestPrimitive, C::Digest: AssociatedOid,

ECDSA ObjectIdentifier which identifies the digest used by default with the Signer and Verifier traits.

To support non-default digest algorithms, use the SignatureWithOid type instead.

const OID: ObjectIdentifier = _

The OID associated with this type.

impl<C: Clone + PrimeCurve> Clone for Signature<C>

fn clone(&self) -> Signature<C>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<C> Debug for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

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

Formats the value using the given formatter.

impl<C, D> DigestSigner<D, Signature<C>> for SigningKey<C>

where C: PrimeCurve + CurveArithmetic + DigestPrimitive, D: Digest + FixedOutput<OutputSize = FieldBytesSize<C>>, Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

Sign message digest using a deterministic ephemeral scalar (k) computed using the algorithm described in RFC6979 § 3.2.

fn try_sign_digest(&self, msg_digest: D) -> Result<Signature<C>>

Attempt to sign the given prehashed message Digest, returning a digital signature on success, or an error if something went wrong.

fn sign_digest(&self, digest: D) -> S

Sign the given prehashed message Digest, returning a signature.

impl<C, D> DigestVerifier<D, Signature<C>> for VerifyingKey<C>

where C: PrimeCurve + CurveArithmetic, D: Digest + FixedOutput<OutputSize = FieldBytesSize<C>>, AffinePoint<C>: VerifyPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

fn verify_digest(&self, msg_digest: D, signature: &Signature<C>) -> Result<()>

Verify the signature against the given Digest output.

impl<C> Display for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

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

Formats the value using the given formatter.

impl<C> From<Signature<C>> for SignatureBytes<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

fn from(signature: Signature<C>) -> SignatureBytes<C>

Converts to this type from the input type.

impl<C> From<Signature<C>> for Signature<C>

where C: PrimeCurve, MaxSize<C>: ArrayLength<u8>, <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArrayLength<u8>,

fn from(sig: Signature<C>) -> Signature<C>

Converts to this type from the input type.

impl<C> From<SignatureWithOid<C>> for Signature<C>

where C: PrimeCurve,

fn from(sig: SignatureWithOid<C>) -> Signature<C>

Converts to this type from the input type.

impl<C> FromStr for Signature<C>

where C: PrimeCurve + CurveArithmetic, SignatureSize<C>: ArrayLength<u8>,

type Err = Error

The associated error which can be returned from parsing.

fn from_str(hex: &str) -> Result<Self>

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

impl<C> LowerHex for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

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

Formats the value using the given formatter.

impl<C: PartialEq + PrimeCurve> PartialEq for Signature<C>

fn eq(&self, other: &Signature<C>) -> 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<C> PrehashSignature for Signature<C>

where C: DigestPrimitive, <FieldBytesSize<C> as Add>::Output: ArrayLength<u8>,

type Digest = <C as DigestPrimitive>::Digest

Preferred Digest algorithm to use when computing this signature type.

impl<C> PrehashSigner<Signature<C>> for SigningKey<C>

where C: PrimeCurve + CurveArithmetic + DigestPrimitive, Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

Sign message prehash using a deterministic ephemeral scalar (k) computed using the algorithm described in RFC6979 § 3.2.

fn sign_prehash(&self, prehash: &[u8]) -> Result<Signature<C>>

Attempt to sign the given message digest, returning a digital signature on success, or an error if something went wrong.

impl<C> PrehashVerifier<Signature<C>> for VerifyingKey<C>

where C: PrimeCurve + CurveArithmetic, AffinePoint<C>: VerifyPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

fn verify_prehash(&self, prehash: &[u8], signature: &Signature<C>) -> Result<()>

Use Self to verify that the provided signature for a given message prehash is authentic.

impl<C, D> RandomizedDigestSigner<D, Signature<C>> for SigningKey<C>

where C: PrimeCurve + CurveArithmetic + DigestPrimitive, D: Digest + FixedOutput<OutputSize = FieldBytesSize<C>>, Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

fn try_sign_digest_with_rng( &self, rng: &mut impl CryptoRngCore, msg_digest: D, ) -> Result<Signature<C>>

Attempt to sign the given prehashed message Digest, returning a digital signature on success, or an error if something went wrong.

fn sign_digest_with_rng(&self, rng: &mut impl CryptoRngCore, digest: D) -> S

Sign the given prehashed message Digest, returning a signature.

impl<C> RandomizedPrehashSigner<Signature<C>> for SigningKey<C>

where C: PrimeCurve + CurveArithmetic + DigestPrimitive, Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

fn sign_prehash_with_rng( &self, rng: &mut impl CryptoRngCore, prehash: &[u8], ) -> Result<Signature<C>>

Attempt to sign the given message digest, returning a digital signature on success, or an error if something went wrong.

impl<C> RandomizedSigner<Signature<C>> for SigningKey<C>

where Self: RandomizedDigestSigner<C::Digest, Signature<C>>, C: PrimeCurve + CurveArithmetic + DigestPrimitive, Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

fn try_sign_with_rng( &self, rng: &mut impl CryptoRngCore, msg: &[u8], ) -> Result<Signature<C>>

Attempt to sign the given message, returning a digital signature on success, or an error if something went wrong.

fn sign_with_rng(&self, rng: &mut impl CryptoRngCore, msg: &[u8]) -> S

Sign the given message and return a digital signature

impl<C> SignatureEncoding for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

type Repr = GenericArray<u8, <<C as Curve>::FieldBytesSize as Add>::Output>

Byte representation of a signature.

fn to_bytes(&self) -> Self::Repr

Encode signature as its byte representation.

fn to_vec(&self) -> Vec<u8>

Encode signature as a byte vector.

fn encoded_len(&self) -> usize

Get the length of this signature when encoded.

impl<C> Signer<Signature<C>> for SigningKey<C>

where C: PrimeCurve + CurveArithmetic + DigestPrimitive, Scalar<C>: Invert<Output = CtOption<Scalar<C>>> + SignPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

Sign message using a deterministic ephemeral scalar (k) computed using the algorithm described in RFC6979 § 3.2.

fn try_sign(&self, msg: &[u8]) -> Result<Signature<C>>

Attempt to sign the given message, returning a digital signature on success, or an error if something went wrong.

fn sign(&self, msg: &[u8]) -> S

Sign the given message and return a digital signature

impl<C> TryFrom<&[u8]> for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

type Error = Error

The type returned in the event of a conversion error.

fn try_from(slice: &[u8]) -> Result<Self>

Performs the conversion.

impl<C> TryFrom<Signature<C>> for Signature<C>

where C: PrimeCurve, MaxSize<C>: ArrayLength<u8>, <FieldBytesSize<C> as Add>::Output: Add<MaxOverhead> + ArrayLength<u8>,

type Error = Error

The type returned in the event of a conversion error.

fn try_from(sig: Signature<C>) -> Result<Signature<C>>

Performs the conversion.

impl<C> UpperHex for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>,

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

Formats the value using the given formatter.

impl<C> Verifier<Signature<C>> for VerifyingKey<C>

where C: PrimeCurve + CurveArithmetic + DigestPrimitive, AffinePoint<C>: VerifyPrimitive<C>, SignatureSize<C>: ArrayLength<u8>,

fn verify(&self, msg: &[u8], signature: &Signature<C>) -> Result<()>

Use Self to verify that the provided signature for a given message bytestring is authentic.

impl<C> Copy for Signature<C>

where C: PrimeCurve, SignatureSize<C>: ArrayLength<u8>, <SignatureSize<C> as ArrayLength<u8>>::ArrayType: Copy,

impl<C: Eq + PrimeCurve> Eq for Signature<C>

impl<C: PrimeCurve> StructuralPartialEq for Signature<C>