Class: EC::Point

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

Instance Method Summary collapse

Constructor Details

#initialize(*args, group: nil) ⇒ Point

Returns a new instance of Point.



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# File 'lib/elliptic.rb', line 28

def initialize( *args, group: nil )
  ## case 1) assume OpenSSL::PKey::EC::Point
  if args.size == 1 && args[0].is_a?( OpenSSL::PKey::EC::Point )
     @pt = args[0]

     ## todo/check: is there a "better" way to get the x/y numbers?
     ## note: octet_string is just a fancy name (technial term) for
     ##           byte/binary string (where a byte is 8-bit, thus octet)
     hex = @pt.to_octet_string( :uncompressed ).unpack( 'H*' )[0]

     ## todo/fix: check for infinity / 0 !!!!
     @x = hex[2,64].to_i(16)       ## skip leading 0x04 marker
     @y = hex[2+64,64].to_i(16)
  else  ## assume x,y with group
     ## rebuild openssl point from octet

     @x = args[0]
     @y = args[1]
     ## encoded_point is the octet string representation of the point.
     ## This must be either a String or an OpenSSL::BN
     ##   was: ("%064x" % @x) + ("%064x" % @y)
     hex = '04' +
           @x.to_s(16).rjust(64, '0') +
           @y.to_s(16).rjust(64, '0')
     bin = [hex].pack( 'H*' )

     ec_group = GROUP[ group || 'secp256k1' ]
     @pt = OpenSSL::PKey::EC::Point.new( ec_group, bin )

     ### or use hex e.g.
     ## hex = '04fc9702847840aaf195de8442ebecedf5b095cdbb9bc716bda9110971b28a49e0ead8564ff0db22209e0374782c093bb899692d524e9d6a6956e7c5ecbcd68284'
     ## bn = OpenSSL::BN.new(hex, 16)    # note: 16=Hexadecimal string encoding
     ## OpenSSL::PKey::EC::Point.new( ec_group, bn )
  end
end

Instance Method Details

#group ⇒ Object 



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# File 'lib/elliptic.rb', line 66

def group() @pt.group; end

#to_bin(format = :uncompressed) ⇒ Object

formats - :compressed | :uncompressed



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# File 'lib/elliptic.rb', line 69

def to_bin( format=:uncompressed )  ## todo/check add alias .b too - why? why not?
  @pt.to_octet_string( format )
end

#to_ec_point ⇒ Object

return OpenSSL::PKey::EC::Point - find a better name? e.g. to_raw/native or such - why? why not?



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# File 'lib/elliptic.rb', line 78

def to_ec_point()  @pt; end

#to_s(format = :uncompressed) ⇒ Object 



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# File 'lib/elliptic.rb', line 73

def to_s( format=:uncompressed )
  to_bin( format ).unpack( 'H*' )[0]
end

#x ⇒ Object 



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# File 'lib/elliptic.rb', line 64

def x()  @x; end

#y ⇒ Object 



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# File 'lib/elliptic.rb', line 65

def y()  @y; end