Struct confidential_identity_v1::Scalar
source · pub struct Scalar { /* private fields */ }
Expand description
The Scalar
struct holds an integer \(s < 2^{255} \) which
represents an element of \(\mathbb Z / \ell\).
Implementations§
source§impl Scalar
impl Scalar
sourcepub fn from_bytes_mod_order(bytes: [u8; 32]) -> Scalar
pub fn from_bytes_mod_order(bytes: [u8; 32]) -> Scalar
Construct a Scalar
by reducing a 256-bit little-endian integer
modulo the group order \( \ell \).
sourcepub fn from_bytes_mod_order_wide(input: &[u8; 64]) -> Scalar
pub fn from_bytes_mod_order_wide(input: &[u8; 64]) -> Scalar
Construct a Scalar
by reducing a 512-bit little-endian integer
modulo the group order \( \ell \).
source§impl Scalar
impl Scalar
sourcepub fn random<R>(rng: &mut R) -> Scalarwhere
R: RngCore + CryptoRng,
pub fn random<R>(rng: &mut R) -> Scalarwhere R: RngCore + CryptoRng,
Return a Scalar
chosen uniformly at random using a user-provided RNG.
Inputs
rng
: any RNG which implements theRngCore + CryptoRng
interface.
Returns
A random scalar within ℤ/lℤ.
Example
extern crate rand_core;
use curve25519_dalek_ng::scalar::Scalar;
use rand_core::OsRng;
let mut csprng = OsRng;
let a: Scalar = Scalar::random(&mut csprng);
sourcepub fn hash_from_bytes<D>(input: &[u8]) -> Scalarwhere
D: Digest<OutputSize = UInt<UInt<UInt<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>, B0>, B0>, B0>> + Default,
pub fn hash_from_bytes<D>(input: &[u8]) -> Scalarwhere D: Digest<OutputSize = UInt<UInt<UInt<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>, B0>, B0>, B0>> + Default,
Hash a slice of bytes into a scalar.
Takes a type parameter D
, which is any Digest
producing 64
bytes (512 bits) of output.
Convenience wrapper around from_hash
.
Example
extern crate sha2;
use sha2::Sha512;
let msg = "To really appreciate architecture, you may even need to commit a murder";
let s = Scalar::hash_from_bytes::<Sha512>(msg.as_bytes());
sourcepub fn from_hash<D>(hash: D) -> Scalarwhere
D: Digest<OutputSize = UInt<UInt<UInt<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>, B0>, B0>, B0>>,
pub fn from_hash<D>(hash: D) -> Scalarwhere D: Digest<OutputSize = UInt<UInt<UInt<UInt<UInt<UInt<UInt<UTerm, B1>, B0>, B0>, B0>, B0>, B0>, B0>>,
Construct a scalar from an existing Digest
instance.
Use this instead of hash_from_bytes
if it is more convenient
to stream data into the Digest
than to pass a single byte
slice.
Example
extern crate sha2;
use sha2::Digest;
use sha2::Sha512;
let mut h = Sha512::new()
.chain("To really appreciate architecture, you may even need to commit a murder.")
.chain("While the programs used for The Manhattan Transcripts are of the most extreme")
.chain("nature, they also parallel the most common formula plot: the archetype of")
.chain("murder. Other phantasms were occasionally used to underline the fact that")
.chain("perhaps all architecture, rather than being about functional standards, is")
.chain("about love and death.");
let s = Scalar::from_hash(h);
println!("{:?}", s.to_bytes());
assert!(s == Scalar::from_bits([ 21, 88, 208, 252, 63, 122, 210, 152,
154, 38, 15, 23, 16, 167, 80, 150,
192, 221, 77, 226, 62, 25, 224, 148,
239, 48, 176, 10, 185, 69, 168, 11, ]));
sourcepub fn to_bytes(&self) -> [u8; 32]
pub fn to_bytes(&self) -> [u8; 32]
Convert this Scalar
to its underlying sequence of bytes.
Example
use curve25519_dalek_ng::scalar::Scalar;
let s: Scalar = Scalar::zero();
assert!(s.to_bytes() == [0u8; 32]);
sourcepub fn as_bytes(&self) -> &[u8; 32]
pub fn as_bytes(&self) -> &[u8; 32]
View the little-endian byte encoding of the integer representing this Scalar.
Example
use curve25519_dalek_ng::scalar::Scalar;
let s: Scalar = Scalar::zero();
assert!(s.as_bytes() == &[0u8; 32]);
sourcepub fn invert(&self) -> Scalar
pub fn invert(&self) -> Scalar
Given a nonzero Scalar
, compute its multiplicative inverse.
Warning
self
MUST be nonzero. If you cannot
prove that this is the case, you SHOULD NOT USE THIS
FUNCTION.
Returns
The multiplicative inverse of the this Scalar
.
Example
use curve25519_dalek_ng::scalar::Scalar;
// x = 2238329342913194256032495932344128051776374960164957527413114840482143558222
let X: Scalar = Scalar::from_bytes_mod_order([
0x4e, 0x5a, 0xb4, 0x34, 0x5d, 0x47, 0x08, 0x84,
0x59, 0x13, 0xb4, 0x64, 0x1b, 0xc2, 0x7d, 0x52,
0x52, 0xa5, 0x85, 0x10, 0x1b, 0xcc, 0x42, 0x44,
0xd4, 0x49, 0xf4, 0xa8, 0x79, 0xd9, 0xf2, 0x04,
]);
// 1/x = 6859937278830797291664592131120606308688036382723378951768035303146619657244
let XINV: Scalar = Scalar::from_bytes_mod_order([
0x1c, 0xdc, 0x17, 0xfc, 0xe0, 0xe9, 0xa5, 0xbb,
0xd9, 0x24, 0x7e, 0x56, 0xbb, 0x01, 0x63, 0x47,
0xbb, 0xba, 0x31, 0xed, 0xd5, 0xa9, 0xbb, 0x96,
0xd5, 0x0b, 0xcd, 0x7a, 0x3f, 0x96, 0x2a, 0x0f,
]);
let inv_X: Scalar = X.invert();
assert!(XINV == inv_X);
let should_be_one: Scalar = &inv_X * &X;
assert!(should_be_one == Scalar::one());
sourcepub fn batch_invert(inputs: &mut [Scalar]) -> Scalar
pub fn batch_invert(inputs: &mut [Scalar]) -> Scalar
Given a slice of nonzero (possibly secret) Scalar
s,
compute their inverses in a batch.
Return
Each element of inputs
is replaced by its inverse.
The product of all inverses is returned.
Warning
All input Scalars
MUST be nonzero. If you cannot
prove that this is the case, you SHOULD NOT USE THIS
FUNCTION.
Example
let mut scalars = [
Scalar::from(3u64),
Scalar::from(5u64),
Scalar::from(7u64),
Scalar::from(11u64),
];
let allinv = Scalar::batch_invert(&mut scalars);
assert_eq!(allinv, Scalar::from(3*5*7*11u64).invert());
assert_eq!(scalars[0], Scalar::from(3u64).invert());
assert_eq!(scalars[1], Scalar::from(5u64).invert());
assert_eq!(scalars[2], Scalar::from(7u64).invert());
assert_eq!(scalars[3], Scalar::from(11u64).invert());
sourcepub fn is_canonical(&self) -> bool
pub fn is_canonical(&self) -> bool
Check whether this Scalar
is the canonical representative mod \(\ell\).
This is intended for uses like input validation, where variable-time code is acceptable.
// 2^255 - 1, since `from_bits` clears the high bit
let _2_255_minus_1 = Scalar::from_bits([0xff;32]);
assert!(!_2_255_minus_1.is_canonical());
let reduced = _2_255_minus_1.reduce();
assert!(reduced.is_canonical());
Trait Implementations§
source§impl<'b> AddAssign<&'b Scalar> for Scalar
impl<'b> AddAssign<&'b Scalar> for Scalar
source§fn add_assign(&mut self, _rhs: &'b Scalar)
fn add_assign(&mut self, _rhs: &'b Scalar)
+=
operation. Read moresource§impl AddAssign<Scalar> for Scalar
impl AddAssign<Scalar> for Scalar
source§fn add_assign(&mut self, rhs: Scalar)
fn add_assign(&mut self, rhs: Scalar)
+=
operation. Read moresource§impl ConditionallySelectable for Scalar
impl ConditionallySelectable for Scalar
source§impl ConstantTimeEq for Scalar
impl ConstantTimeEq for Scalar
source§impl<'de> Deserialize<'de> for Scalar
impl<'de> Deserialize<'de> for Scalar
source§fn deserialize<D>(
deserializer: D
) -> Result<Scalar, <D as Deserializer<'de>>::Error>where
D: Deserializer<'de>,
fn deserialize<D>( deserializer: D ) -> Result<Scalar, <D as Deserializer<'de>>::Error>where D: Deserializer<'de>,
source§impl From<u64> for Scalar
impl From<u64> for Scalar
source§fn from(x: u64) -> Scalar
fn from(x: u64) -> Scalar
Construct a scalar from the given u64
.
Inputs
An u64
to convert to a Scalar
.
Returns
A Scalar
corresponding to the input u64
.
Example
use curve25519_dalek_ng::scalar::Scalar;
let fourtytwo = Scalar::from(42u64);
let six = Scalar::from(6u64);
let seven = Scalar::from(7u64);
assert!(fourtytwo == six * seven);
source§impl<'a, 'b> Mul<&'a EdwardsBasepointTable> for &'b Scalar
impl<'a, 'b> Mul<&'a EdwardsBasepointTable> for &'b Scalar
source§fn mul(self, basepoint_table: &'a EdwardsBasepointTable) -> EdwardsPoint
fn mul(self, basepoint_table: &'a EdwardsBasepointTable) -> EdwardsPoint
Construct an EdwardsPoint
from a Scalar
\(a\) by
computing the multiple \(aB\) of this basepoint \(B\).
§type Output = EdwardsPoint
type Output = EdwardsPoint
*
operator.source§impl<'a, 'b> Mul<&'a RistrettoBasepointTable> for &'b Scalar
impl<'a, 'b> Mul<&'a RistrettoBasepointTable> for &'b Scalar
§type Output = RistrettoPoint
type Output = RistrettoPoint
*
operator.source§fn mul(self, basepoint_table: &'a RistrettoBasepointTable) -> RistrettoPoint
fn mul(self, basepoint_table: &'a RistrettoBasepointTable) -> RistrettoPoint
*
operation. Read moresource§impl<'a, 'b> Mul<&'b EdwardsPoint> for &'a Scalar
impl<'a, 'b> Mul<&'b EdwardsPoint> for &'a Scalar
source§fn mul(self, point: &'b EdwardsPoint) -> EdwardsPoint
fn mul(self, point: &'b EdwardsPoint) -> EdwardsPoint
Scalar multiplication: compute scalar * self
.
For scalar multiplication of a basepoint,
EdwardsBasepointTable
is approximately 4x faster.
§type Output = EdwardsPoint
type Output = EdwardsPoint
*
operator.source§impl<'b> Mul<&'b EdwardsPoint> for Scalar
impl<'b> Mul<&'b EdwardsPoint> for Scalar
§type Output = EdwardsPoint
type Output = EdwardsPoint
*
operator.source§fn mul(self, rhs: &'b EdwardsPoint) -> EdwardsPoint
fn mul(self, rhs: &'b EdwardsPoint) -> EdwardsPoint
*
operation. Read moresource§impl<'a, 'b> Mul<&'b MontgomeryPoint> for &'a Scalar
impl<'a, 'b> Mul<&'b MontgomeryPoint> for &'a Scalar
§type Output = MontgomeryPoint
type Output = MontgomeryPoint
*
operator.source§fn mul(self, point: &'b MontgomeryPoint) -> MontgomeryPoint
fn mul(self, point: &'b MontgomeryPoint) -> MontgomeryPoint
*
operation. Read moresource§impl<'b> Mul<&'b MontgomeryPoint> for Scalar
impl<'b> Mul<&'b MontgomeryPoint> for Scalar
§type Output = MontgomeryPoint
type Output = MontgomeryPoint
*
operator.source§fn mul(self, rhs: &'b MontgomeryPoint) -> MontgomeryPoint
fn mul(self, rhs: &'b MontgomeryPoint) -> MontgomeryPoint
*
operation. Read moresource§impl<'a, 'b> Mul<&'b RistrettoPoint> for &'a Scalar
impl<'a, 'b> Mul<&'b RistrettoPoint> for &'a Scalar
source§fn mul(self, point: &'b RistrettoPoint) -> RistrettoPoint
fn mul(self, point: &'b RistrettoPoint) -> RistrettoPoint
Scalar multiplication: compute self * scalar
.
§type Output = RistrettoPoint
type Output = RistrettoPoint
*
operator.source§impl<'b> Mul<&'b RistrettoPoint> for Scalar
impl<'b> Mul<&'b RistrettoPoint> for Scalar
§type Output = RistrettoPoint
type Output = RistrettoPoint
*
operator.source§fn mul(self, rhs: &'b RistrettoPoint) -> RistrettoPoint
fn mul(self, rhs: &'b RistrettoPoint) -> RistrettoPoint
*
operation. Read moresource§impl<'a> Mul<EdwardsPoint> for &'a Scalar
impl<'a> Mul<EdwardsPoint> for &'a Scalar
§type Output = EdwardsPoint
type Output = EdwardsPoint
*
operator.source§fn mul(self, rhs: EdwardsPoint) -> EdwardsPoint
fn mul(self, rhs: EdwardsPoint) -> EdwardsPoint
*
operation. Read moresource§impl Mul<EdwardsPoint> for Scalar
impl Mul<EdwardsPoint> for Scalar
§type Output = EdwardsPoint
type Output = EdwardsPoint
*
operator.source§fn mul(self, rhs: EdwardsPoint) -> EdwardsPoint
fn mul(self, rhs: EdwardsPoint) -> EdwardsPoint
*
operation. Read moresource§impl<'a> Mul<MontgomeryPoint> for &'a Scalar
impl<'a> Mul<MontgomeryPoint> for &'a Scalar
§type Output = MontgomeryPoint
type Output = MontgomeryPoint
*
operator.source§fn mul(self, rhs: MontgomeryPoint) -> MontgomeryPoint
fn mul(self, rhs: MontgomeryPoint) -> MontgomeryPoint
*
operation. Read moresource§impl Mul<MontgomeryPoint> for Scalar
impl Mul<MontgomeryPoint> for Scalar
§type Output = MontgomeryPoint
type Output = MontgomeryPoint
*
operator.source§fn mul(self, rhs: MontgomeryPoint) -> MontgomeryPoint
fn mul(self, rhs: MontgomeryPoint) -> MontgomeryPoint
*
operation. Read moresource§impl<'a> Mul<RistrettoPoint> for &'a Scalar
impl<'a> Mul<RistrettoPoint> for &'a Scalar
§type Output = RistrettoPoint
type Output = RistrettoPoint
*
operator.source§fn mul(self, rhs: RistrettoPoint) -> RistrettoPoint
fn mul(self, rhs: RistrettoPoint) -> RistrettoPoint
*
operation. Read moresource§impl Mul<RistrettoPoint> for Scalar
impl Mul<RistrettoPoint> for Scalar
§type Output = RistrettoPoint
type Output = RistrettoPoint
*
operator.source§fn mul(self, rhs: RistrettoPoint) -> RistrettoPoint
fn mul(self, rhs: RistrettoPoint) -> RistrettoPoint
*
operation. Read moresource§impl<'b> MulAssign<&'b Scalar> for Scalar
impl<'b> MulAssign<&'b Scalar> for Scalar
source§fn mul_assign(&mut self, _rhs: &'b Scalar)
fn mul_assign(&mut self, _rhs: &'b Scalar)
*=
operation. Read moresource§impl MulAssign<Scalar> for Scalar
impl MulAssign<Scalar> for Scalar
source§fn mul_assign(&mut self, rhs: Scalar)
fn mul_assign(&mut self, rhs: Scalar)
*=
operation. Read moresource§impl PartialEq<Scalar> for Scalar
impl PartialEq<Scalar> for Scalar
source§impl Serialize for Scalar
impl Serialize for Scalar
source§fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>where
S: Serializer,
fn serialize<S>( &self, serializer: S ) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error>where S: Serializer,
source§impl<'b> SubAssign<&'b Scalar> for Scalar
impl<'b> SubAssign<&'b Scalar> for Scalar
source§fn sub_assign(&mut self, _rhs: &'b Scalar)
fn sub_assign(&mut self, _rhs: &'b Scalar)
-=
operation. Read moresource§impl SubAssign<Scalar> for Scalar
impl SubAssign<Scalar> for Scalar
source§fn sub_assign(&mut self, rhs: Scalar)
fn sub_assign(&mut self, rhs: Scalar)
-=
operation. Read moreimpl Copy for Scalar
impl Eq for Scalar
Auto Trait Implementations§
impl RefUnwindSafe for Scalar
impl Send for Scalar
impl Sync for Scalar
impl Unpin for Scalar
impl UnwindSafe for Scalar
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<T> ConditionallyNegatable for Twhere
T: ConditionallySelectable,
&'a T: for<'a> Neg<Output = T>,
impl<T> ConditionallyNegatable for Twhere T: ConditionallySelectable, &'a T: for<'a> Neg<Output = T>,
source§fn conditional_negate(&mut self, choice: Choice)
fn conditional_negate(&mut self, choice: Choice)
§impl<T> Downcast for Twhere
T: Any,
impl<T> Downcast for Twhere T: Any,
§fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
Box<dyn Trait>
(where Trait: Downcast
) to Box<dyn Any>
. Box<dyn Any>
can
then be further downcast
into Box<ConcreteType>
where ConcreteType
implements Trait
.§fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
Rc<Trait>
(where Trait: Downcast
) to Rc<Any>
. Rc<Any>
can then be
further downcast
into Rc<ConcreteType>
where ConcreteType
implements Trait
.§fn as_any(&self) -> &(dyn Any + 'static)
fn as_any(&self) -> &(dyn Any + 'static)
&Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &Any
’s vtable from &Trait
’s.§fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
&mut Trait
(where Trait: Downcast
) to &Any
. This is needed since Rust cannot
generate &mut Any
’s vtable from &mut Trait
’s.§impl<T> Instrument for T
impl<T> Instrument for T
§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
§impl<S, T> UncheckedInto<T> for Swhere
T: UncheckedFrom<S>,
impl<S, T> UncheckedInto<T> for Swhere T: UncheckedFrom<S>,
§fn unchecked_into(self) -> T
fn unchecked_into(self) -> T
unchecked_from
.