Struct rubedo::crypto::SigningKey
source · pub struct SigningKey { /* private fields */ }
Expand description
An ed25519 signing key which can be used to produce signatures.
This is a wrapper around ed25519_dalek::SigningKey
, which provides
additional functionality, including serialisation and deserialisation using
Serde, via the implementation of the
ByteSized
and ByteSizedFull
traits.
§See also
Implementations§
source§impl SigningKey
impl SigningKey
sourcepub fn generate<R: CryptoRngCore + ?Sized>(csprng: &mut R) -> Self
pub fn generate<R: CryptoRngCore + ?Sized>(csprng: &mut R) -> Self
Generates an ed25519 SigningKey
.
This function exists to return the wrapper type SigningKey
rather
than the inner type ed25519_dalek::SigningKey
.
sourcepub fn into_inner(self) -> RealSigningKey
pub fn into_inner(self) -> RealSigningKey
Consumes the SigningKey
and returns the inner
ed25519_dalek::SigningKey
.
sourcepub fn verifying_key(&self) -> VerifyingKey
pub fn verifying_key(&self) -> VerifyingKey
Returns the VerifyingKey
for this SigningKey
.
This function exists to return the wrapper type VerifyingKey
rather
than the inner type ed25519_dalek::VerifyingKey
.
Methods from Deref<Target = RealSigningKey>§
sourcepub fn to_keypair_bytes(&self) -> [u8; 64]
pub fn to_keypair_bytes(&self) -> [u8; 64]
Convert this signing key to a 64-byte keypair.
§Returns
An array of bytes, [u8; KEYPAIR_LENGTH]
. The first
SECRET_KEY_LENGTH
of bytes is the SecretKey
, and the next
PUBLIC_KEY_LENGTH
bytes is the VerifyingKey
(the same as other
libraries, such as Adam Langley’s ed25519 Golang
implementation). It is guaranteed that
the encoded public key is the one derived from the encoded secret key.
sourcepub fn verifying_key(&self) -> VerifyingKey
pub fn verifying_key(&self) -> VerifyingKey
Get the VerifyingKey
for this SigningKey
.
sourcepub fn verify(&self, message: &[u8], signature: &Signature) -> Result<(), Error>
pub fn verify(&self, message: &[u8], signature: &Signature) -> Result<(), Error>
Verify a signature on a message with this signing key’s public key.
sourcepub fn verify_strict(
&self,
message: &[u8],
signature: &Signature
) -> Result<(), Error>
pub fn verify_strict( &self, message: &[u8], signature: &Signature ) -> Result<(), Error>
Strictly verify a signature on a message with this signing key’s public key.
§On The (Multiple) Sources of Malleability in Ed25519 Signatures
This version of verification is technically non-RFC8032 compliant. The following explains why.
- Scalar Malleability
The authors of the RFC explicitly stated that verification of an ed25519
signature must fail if the scalar s
is not properly reduced mod \ell:
To verify a signature on a message M using public key A, with F being 0 for Ed25519ctx, 1 for Ed25519ph, and if Ed25519ctx or Ed25519ph is being used, C being the context, first split the signature into two 32-octet halves. Decode the first half as a point R, and the second half as an integer S, in the range 0 <= s < L. Decode the public key A as point A’. If any of the decodings fail (including S being out of range), the signature is invalid.)
All verify_*()
functions within ed25519-dalek perform this check.
- Point malleability
The authors of the RFC added in a malleability check to step #3 in
§5.1.7, for small torsion components in the R
value of the signature,
which is not strictly required, as they state:
Check the group equation [8][S]B = [8]R + [8][k]A’. It’s sufficient, but not required, to instead check [S]B = R + [k]A’.
§History of Malleability Checks
As originally defined (cf. the “Malleability” section in the README of this repo), ed25519 signatures didn’t consider any form of malleability to be an issue. Later the scalar malleability was considered important. Still later, particularly with interests in cryptocurrency design and in unique identities (e.g. for Signal users, Tor onion services, etc.), the group element malleability became a concern.
However, libraries had already been created to conform to the original definition. One well-used library in particular even implemented the group element malleability check, but only for batch verification! Which meant that even using the same library, a single signature could verify fine individually, but suddenly, when verifying it with a bunch of other signatures, the whole batch would fail!
§“Strict” Verification
This method performs both of the above signature malleability checks.
It must be done as a separate method because one doesn’t simply get to change the definition of a cryptographic primitive ten years after-the-fact with zero consideration for backwards compatibility in hardware and protocols which have it already have the older definition baked in.
§Return
Returns Ok(())
if the signature is valid, and Err
otherwise.
sourcepub fn to_scalar_bytes(&self) -> [u8; 32]
pub fn to_scalar_bytes(&self) -> [u8; 32]
Convert this signing key into a byte representation of an unreduced, unclamped Curve25519
scalar. This is NOT the same thing as self.to_scalar().to_bytes()
, since to_scalar()
performs a clamping step, which changes the value of the resulting scalar.
This can be used for performing X25519 Diffie-Hellman using Ed25519 keys. The bytes output
by this function are a valid corresponding StaticSecret
for the X25519 public key given by self.verifying_key().to_montgomery()
.
§Note
We do NOT recommend using a signing/verifying key for encryption. Signing keys are usually long-term keys, while keys used for key exchange should rather be ephemeral. If you can help it, use a separate key for encryption.
For more information on the security of systems which use the same keys for both signing and Diffie-Hellman, see the paper On using the same key pair for Ed25519 and an X25519 based KEM.
sourcepub fn to_scalar(&self) -> Scalar
pub fn to_scalar(&self) -> Scalar
Convert this signing key into a Curve25519 scalar. This is computed by clamping and
reducing the output of Self::to_scalar_bytes
.
This can be used anywhere where a Curve25519 scalar is used as a private key, e.g., in
crypto_box
.
§Note
We do NOT recommend using a signing/verifying key for encryption. Signing keys are usually long-term keys, while keys used for key exchange should rather be ephemeral. If you can help it, use a separate key for encryption.
For more information on the security of systems which use the same keys for both signing and Diffie-Hellman, see the paper On using the same key pair for Ed25519 and an X25519 based KEM.
Trait Implementations§
source§impl ByteSized<32> for SigningKey
impl ByteSized<32> for SigningKey
source§fn to_bytes(&self) -> [u8; 32]
fn to_bytes(&self) -> [u8; 32]
source§fn from_bytes(bytes: [u8; 32]) -> Self
fn from_bytes(bytes: [u8; 32]) -> Self
source§fn from_base64(encoded: &str) -> Result<Self, DecodeError>
fn from_base64(encoded: &str) -> Result<Self, DecodeError>
source§impl Clone for SigningKey
impl Clone for SigningKey
source§fn clone(&self) -> SigningKey
fn clone(&self) -> SigningKey
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for SigningKey
impl Debug for SigningKey
source§impl Default for SigningKey
impl Default for SigningKey
source§impl Deref for SigningKey
impl Deref for SigningKey
source§impl<'de> Deserialize<'de> for SigningKey
impl<'de> Deserialize<'de> for SigningKey
source§fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>where
D: Deserializer<'de>,
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>where
D: Deserializer<'de>,
source§impl Display for SigningKey
impl Display for SigningKey
source§impl ForceFrom<&[u8]> for SigningKey
impl ForceFrom<&[u8]> for SigningKey
source§fn force_from(b: &[u8]) -> Self
fn force_from(b: &[u8]) -> Self
Converts a &[u8]
to a SigningKey
.
Note that if the incoming [u8]
is too long to fit, it will be
truncated without error or warning. If there is not enough data, it will
be padded with zeroes. If this situation needs checking, use
try_from()
instead.
source§impl<const N: usize> ForceFrom<&[u8; N]> for SigningKey
impl<const N: usize> ForceFrom<&[u8; N]> for SigningKey
source§fn force_from(b: &[u8; N]) -> Self
fn force_from(b: &[u8; N]) -> Self
Converts a &[u8; N]
to a SigningKey
.
Note that if the incoming [u8; N]
is too long to fit, it will be
truncated without error or warning. If there is not enough data, it will
be padded with zeroes. If this situation needs checking, use
try_from()
instead.
source§impl ForceFrom<&Vec<u8>> for SigningKey
impl ForceFrom<&Vec<u8>> for SigningKey
source§fn force_from(v: &Vec<u8>) -> Self
fn force_from(v: &Vec<u8>) -> Self
Converts a &Vec[u8]
to a SigningKey
.
Note that if the incoming Vec<u8>
is too long to fit, it will
be truncated without error or warning. If there is not enough data, it
will be padded with zeroes. If this situation needs checking, use
try_from()
instead.
source§impl ForceFrom<Vec<u8>> for SigningKey
impl ForceFrom<Vec<u8>> for SigningKey
source§fn force_from(v: Vec<u8>) -> Self
fn force_from(v: Vec<u8>) -> Self
Converts a Vec<u8>
to a SigningKey
.
Note that if the incoming Vec<u8>
is too long to fit, it will
be truncated without error or warning. If there is not enough data, it
will be padded with zeroes. If this situation needs checking, use
try_from()
instead.
source§impl From<&SigningKey> for SigningKey
impl From<&SigningKey> for SigningKey
source§fn from(key: &RealSigningKey) -> Self
fn from(key: &RealSigningKey) -> Self
Converts a &ed25519_dalek::SigningKey
to
a SigningKey
.
source§impl From<SigningKey> for SigningKey
impl From<SigningKey> for SigningKey
source§fn from(key: RealSigningKey) -> Self
fn from(key: RealSigningKey) -> Self
Converts a ed25519_dalek::SigningKey
to a SigningKey
.
source§impl FromStr for SigningKey
impl FromStr for SigningKey
source§impl Hash for SigningKey
impl Hash for SigningKey
source§impl PartialEq for SigningKey
impl PartialEq for SigningKey
source§fn eq(&self, other: &SigningKey) -> bool
fn eq(&self, other: &SigningKey) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl Serialize for SigningKey
impl Serialize for SigningKey
source§impl TryFrom<&[u8]> for SigningKey
impl TryFrom<&[u8]> for SigningKey
source§impl TryFrom<&String> for SigningKey
impl TryFrom<&String> for SigningKey
source§impl TryFrom<&str> for SigningKey
impl TryFrom<&str> for SigningKey
source§impl<'a> TryFrom<Cow<'a, str>> for SigningKey
impl<'a> TryFrom<Cow<'a, str>> for SigningKey
source§fn try_from(s: Cow<'a, str>) -> Result<Self, Self::Error>
fn try_from(s: Cow<'a, str>) -> Result<Self, Self::Error>
Converts a clone-on-write string to a SigningKey
.
§type Error = ByteSizedError
type Error = ByteSizedError
source§impl TryFrom<String> for SigningKey
impl TryFrom<String> for SigningKey
impl ByteSizedFull<32> for SigningKey
impl Eq for SigningKey
impl StructuralPartialEq for SigningKey
Auto Trait Implementations§
impl Freeze for SigningKey
impl RefUnwindSafe for SigningKey
impl Send for SigningKey
impl Sync for SigningKey
impl Unpin for SigningKey
impl UnwindSafe for SigningKey
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.