Class: WebAuthn::AttestedCredentialData

Inherits:
Object
  • Object
show all
Defined in:
lib/web_authn/attested_credential_data.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aaguid:, credential_id:, public_key:) ⇒ AttestedCredentialData

Returns a new instance of AttestedCredentialData.



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# File 'lib/web_authn/attested_credential_data.rb', line 5

def initialize(aaguid:, credential_id:, public_key:)
  self.aaguid = aaguid
  self.credential_id = credential_id
  self.public_key = public_key
end

Instance Attribute Details

#aaguid ⇒ Object

Returns the value of attribute aaguid.



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# File 'lib/web_authn/attested_credential_data.rb', line 3

def aaguid
  @aaguid
end

#credential_id ⇒ Object

Returns the value of attribute credential_id.



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# File 'lib/web_authn/attested_credential_data.rb', line 3

def credential_id
  @credential_id
end

#public_key ⇒ Object

Returns the value of attribute public_key.



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# File 'lib/web_authn/attested_credential_data.rb', line 3

def public_key
  @public_key
end

Class Method Details

.decode(attested_credential_data) ⇒ Object 



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# File 'lib/web_authn/attested_credential_data.rb', line 12

def decode(attested_credential_data)
  length = (
    ((attested_credential_data.getbyte(16) << 8) & 0xFF) +
    (attested_credential_data.getbyte(17) & 0xFF)
  )
  aaguid,
  credential_id,
  _encoded_cose_key_ = [
    attested_credential_data.byteslice(0...16),
    attested_credential_data.byteslice(18...(18 + length)),
    attested_credential_data.byteslice((18 + length)..-1),
  ]
  cose_key = COSE::Key::EC2.from_cbor(_encoded_cose_key_)
  curve_name = case cose_key.curve
  when 1
    'prime256v1'
  when 2
    'secp384r1'
  when 3
    'secp521r1'
  else
    raise NotImplementedError, 'Non-supported EC curve'
  end
  ec_key = OpenSSL::PKey::EC.new curve_name
  ec_key.public_key = OpenSSL::PKey::EC::Point.new(
    OpenSSL::PKey::EC::Group.new(curve_name),
    OpenSSL::BN.new([
      '04' +
      cose_key.x_coordinate.unpack('H*').first +
      cose_key.y_coordinate.unpack('H*').first
    ].pack('H*'), 2)
  )
  new(
    aaguid: Base64.urlsafe_encode64(aaguid, padding: false),
    credential_id: Base64.urlsafe_encode64(credential_id, padding: false),
    public_key: ec_key
  )
end