Class: Noise::Functions::DH::ED25519

Inherits:
Object
  • Object
show all
Defined in:
lib/noise/functions/dh/ed25519.rb

Constant Summary collapse

DHLEN = 
32

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.from_private(private_key) ⇒ Object 



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# File 'lib/noise/functions/dh/ed25519.rb', line 35

def self.from_private(private_key)
  public_key = RbNaCl::GroupElements::Curve25519.base.mult(private_key)
  Noise::Key.new(private_key, public_key.to_bytes)
end

Instance Method Details

#dh(private_key, public_key) ⇒ Object

Computes the X25519 shared secret for the given remote public key.

RbNaCl reports a public key it cannot use in two different ways: a wrong length raises RbNaCl::LengthError, and an all-zero or low-order point raises RbNaCl::CryptoError. Both are translated to InvalidPublicKeyError so that a caller handling a peer-supplied key rescues the same class for every DH function. The length is checked before the call so that RbNaCl::LengthError raised for a malformed private key keeps propagating as itself.



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# File 'lib/noise/functions/dh/ed25519.rb', line 23

def dh(private_key, public_key)
  raise Noise::Exceptions::InvalidPublicKeyError, public_key unless public_key.bytesize == DHLEN

  RbNaCl::GroupElement.new(public_key).mult(private_key).to_bytes
rescue RbNaCl::CryptoError
  raise Noise::Exceptions::InvalidPublicKeyError, public_key
end

#dhlen ⇒ Object 



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# File 'lib/noise/functions/dh/ed25519.rb', line 31

def dhlen
  DHLEN
end

#generate_keypair ⇒ Object 



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# File 'lib/noise/functions/dh/ed25519.rb', line 8

def generate_keypair
  private_key = 1 + SecureRandom.random_number(RbNaCl::GroupElement::STANDARD_GROUP_ORDER - 1)
  scalar_as_string = ECDSA::Format::IntegerOctetString.encode(private_key, 32)
  public_key = RbNaCl::GroupElements::Curve25519.base.mult(scalar_as_string)
  Noise::Key.new(ECDSA::Format::IntegerOctetString.encode(private_key, 32), public_key.to_bytes)
end