lib/rmega/crypto/rsa.rb in rmega-0.1.7 vs lib/rmega/crypto/rsa.rb in rmega-0.2.0

@@ -1,21 +1,30 @@
-require 'execjs'
-
 module Rmega
   module Crypto
     module Rsa
-      extend self
-
-      def script_path
-        File.join File.dirname(__FILE__), 'rsa_mega.js'
+      def powm(b, p, m)
+        if p == 1
+          b % m
+        elsif (p & 0x1) == 0
+          t = powm(b, p >> 1, m)
+          (t * t) % m
+        else
+          (b * powm(b, p-1, m)) % m
+        end
       end
 
-      def context
-        @context ||= ExecJS.compile File.read(script_path)
-      end
-
-      def decrypt(t, privk)
-        context.call "RSAdecrypt", t, privk[2], privk[0], privk[1], privk[3]
+      def rsa_decrypt(m, pqdu)
+        p, q, d, u = pqdu
+        if p && q && u
+          m1 = powm(m, d % (p - 1), p)
+          m2 = powm(m, d % (q - 1), q)
+          h = m2 - m1
+          h = h + q if h < 0
+          h = h * u % q
+          h * p + m1
+        else
+          pow_m(m, d, p * q)
+        end
       end
     end
   end
 end