class Ed25519::Point

• Ed25519::Point
• Reference
• Object

Overview

** Default Point works in affine coordinates: (x, y) /

Defined in:

Constant Summary

BASE = Point.new(Ed25519::Curve::Gx, Ed25519::Curve::Gy)

Base point aka generator public_key = Point::BASE * private_key

ZERO = Point.new(Zero, One)

Identity point aka point at infinity point = point + zero_point

Constructors

• .new(x : BigInt, y : BigInt)

Class Method Summary

• .from_hex(hex : Hex, strict = true)

  Converts hash string or Bytes to Point.

• .from_private_key(private_key : PrivKey)

Instance Method Summary

• #==(other : Point) : Bool
• #_set_window_size(window_size : Int32)

  "Private method", don't use it directly.

• #_window_size : Int32

  We calculate precomputes for elliptic curve point multiplication using windowed method.

• #_window_size=(_window_size : Int32)

  We calculate precomputes for elliptic curve point multiplication using windowed method.

• #add(other : Point)
• #equals(other : Point) : Bool
• #finialize

  Note: This method is not in the original typescript implementation.

• #is_torsion_free : Bool
• #multiply(scalar : Int) : Point

  ** Constant time multiplication.

• #negate
• #subtract(other : Point)
• #to_hex : String

  Same as to_raw_bytes, but returns string.

• #to_raw_bytes : Bytes

  There can always be only two x values (x, -x) for any y When compressing point, it's enough to only store its y coordinate and use the last byte to encode sign of x.

• #to_x25519 : Bytes

  ** Converts to Montgomery aka x coordinate of curve25519.

• #x : BigInt
• #x=(x : BigInt)
• #y : BigInt
• #y=(y : BigInt)

Constructor Detail

Class Method Detail

Instance Method Detail

u, v: curve25519 coordinates
x, y: ed25519 coordinates
(u, v) = ((1+y)/(1-y), sqrt(-486664)*u/x)
(x, y) = (sqrt(-486664)*u/v, (u-1)/(u+1))