Struct test_dalek_docs::edwards::EdwardsPoint

source · 
pub struct EdwardsPoint { /* private fields */ }
Expand description

An EdwardsPoint represents a point on the Edwards form of Curve25519.

Implementations

Convert this EdwardsPoint on the Edwards model to the corresponding MontgomeryPoint on the Montgomery model.

This function has one exceptional case; the identity point of the Edwards curve is sent to the 2-torsion point \((0,0)\) on the Montgomery curve.

Note that this is a one-way conversion, since the Montgomery model does not retain sign information.

Compress this point to CompressedEdwardsY format.

👎Deprecated since 4.0.0: previously named hash_from_bytes, this is not a secure hash function

Maps the digest of the input bytes to the curve. This is NOT a hash-to-curve function, as it produces points with a non-uniform distribution. Rather, it performs something that resembles (but is not) half of the hash_to_curve function from the Elligator2 spec.

Compute \(aA + bB\) in variable time, where \(B\) is the Ed25519 basepoint.

Multiply by the cofactor: return \([8]P\).

Determine if this point is of small order.

Return
  • true if self is in the torsion subgroup \( \mathcal E[8] \);
  • false if self is not in the torsion subgroup \( \mathcal E[8] \).
Example
use curve25519_dalek::constants;

// Generator of the prime-order subgroup
let P = constants::ED25519_BASEPOINT_POINT;
// Generator of the torsion subgroup
let Q = constants::EIGHT_TORSION[1];

// P has large order
assert_eq!(P.is_small_order(), false);

// Q has small order
assert_eq!(Q.is_small_order(), true);

Determine if this point is “torsion-free”, i.e., is contained in the prime-order subgroup.

Return
  • true if self has zero torsion component and is in the prime-order subgroup;
  • false if self has a nonzero torsion component and is not in the prime-order subgroup.
Example
use curve25519_dalek::constants;

// Generator of the prime-order subgroup
let P = constants::ED25519_BASEPOINT_POINT;
// Generator of the torsion subgroup
let Q = constants::EIGHT_TORSION[1];

// P is torsion-free
assert_eq!(P.is_torsion_free(), true);

// P + Q is not torsion-free
assert_eq!((P+Q).is_torsion_free(), false);

Trait Implementations

The resulting type after applying the + operator.
Performs the + operation. Read more
The resulting type after applying the + operator.
Performs the + operation. Read more
The resulting type after applying the + operator.
Performs the + operation. Read more
The resulting type after applying the + operator.
Performs the + operation. Read more
The resulting type after applying the + operator.
Performs the + operation. Read more
The resulting type after applying the + operator.
Performs the + operation. Read more
Performs the += operation. Read more
Performs the += operation. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Select a or b according to choice. Read more
Conditionally assign other to self, according to choice. Read more
Conditionally swap self and other if choice == 1; otherwise, reassign both unto themselves. Read more
Determine if two items are equal. Read more
Formats the value using the given formatter. Read more
Returns the “default value” for a type. Read more
Converts to this type from the input type.
Converts to this type from the input type.
Returns the identity element of the curve. Can be used as a constructor. Read more

Scalar multiplication: compute scalar * self.

For scalar multiplication of a basepoint, EdwardsBasepointTable is approximately 4x faster.

The resulting type after applying the * operator.
The resulting type after applying the * operator.
Performs the * operation. Read more

Scalar multiplication: compute scalar * self.

For scalar multiplication of a basepoint, EdwardsBasepointTable is approximately 4x faster.

The resulting type after applying the * operator.
The resulting type after applying the * operator.
Performs the * operation. Read more
The resulting type after applying the * operator.
Performs the * operation. Read more
The resulting type after applying the * operator.
Performs the * operation. Read more
The resulting type after applying the * operator.
Performs the * operation. Read more
The resulting type after applying the * operator.
Performs the * operation. Read more
Performs the *= operation. Read more
Performs the *= operation. Read more
The type of point being multiplied, e.g., RistrettoPoint.
Given an iterator of (possibly secret) scalars and an iterator of public points, compute $$ Q = c_1 P_1 + \cdots + c_n P_n. $$ Read more
The resulting type after applying the - operator.
Performs the unary - operation. Read more
The resulting type after applying the - operator.
Performs the unary - operation. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. Read more
The resulting type after applying the - operator.
Performs the - operation. Read more
The resulting type after applying the - operator.
Performs the - operation. Read more
The resulting type after applying the - operator.
Performs the - operation. Read more
The resulting type after applying the - operator.
Performs the - operation. Read more
The resulting type after applying the - operator.
Performs the - operation. Read more
The resulting type after applying the - operator.
Performs the - operation. Read more
Performs the -= operation. Read more
Performs the -= operation. Read more
Method which takes an iterator and generates Self from the elements by “summing up” the items. Read more
The type of point being multiplied, e.g., RistrettoPoint.
Given an iterator of public scalars and an iterator of Options of points, compute either Some(Q), where $$ Q = c_1 P_1 + \cdots + c_n P_n, $$ if all points were Some(P_i), or else return None. Read more

Reset this CompressedEdwardsPoint to the identity element.

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
Numeric cast from self to T.
Negate self if choice == Choice(1); otherwise, leave it unchanged. Read more

Returns the argument unchanged.

Safe lossless bitwise transmute from T to Self.
Numeric cast from T to Self.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

Safe lossless bitwise transmute from self to T.
Return true if this element is the identity element of the curve.
Should always be Self
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.