Class: AquaticPrime

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

Overview

AquaticPrime instances are associated with a given public/private key pair, and generate signed license plists for input Hash instances.

Instance Method Summary collapse

Constructor Details

#initialize(pubKey, privKey) ⇒ AquaticPrime

Returns a new AquaticPrime generator with the given public and private keys. Keys should be provided as hex strings.



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# File 'lib/aquaticprime.rb', line 42

def initialize(pubKey, privKey)
  @pubKey = pubKey
  @privKey = privKey
end

Instance Method Details

#license_data(license_info) ⇒ Object

Returns a String containing a signed license plist based on the given license_info Hash. The result is suitable content for a license file via a download, email attachment, or any other delivery mechanism to the end user.



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# File 'lib/aquaticprime.rb', line 71

def license_data(license_info)
  signed_license_info = license_info.dup
  
  # Sign the license info.
  # If a value in the plist is a StringIO object, it handily ends up as a base64-encoded <data> key
	signed_license_info['Signature'] = StringIO.new(signature(license_info))
	
	signed_license_info.to_plist
end

#signature(information) ⇒ Object

Calculates the cryptographic signature for a given Hash, returned as a String. This is generally only of internal interest, but on rare instances clients may wish to calculate this value.



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# File 'lib/aquaticprime.rb', line 51

def signature(information)
	total = information.sort{|a,b| a[0].downcase <=> b[0].downcase || a[0] <=> b[0]}.map{|key,value| value}.join('')
 
	hash = Digest::SHA1.hexdigest(total)
	hash = '0001' + ('ff' * 105) + '00' + hash

	sig = Math.powmod(hash.hex, @privKey.hex, @pubKey.hex)

  # Convert from a big number to a binary string.
  sig = sig.to_s(16)
	sig = ('0' * (256 - sig.length)) + sig
  sig = sig.unpack('a2' * (sig.length/2)).map { |x| x.hex }.pack('c' * (sig.length/2))

	sig
end