code: func NewPublic(x,y []byte) (*ecdsa.PublicKey) {
  	return &ecdsa.PublicKey{ Curve: curve(len(x)), 
  							 X:new(big.Int).SetBytes(x), 
  							 Y:new(big.Int).SetBytes(y) }
  }
docs: // NewPublic constructs ecdsa.PublicKey from given (X,Y)