Add bin and edit workflow

bin/gems/pdf-reader-2.14.1/lib/pdf/reader/rc4_security_handler.rb

@@ -0,0 +1,38 @@
+# coding: utf-8
+# typed: strict
+# frozen_string_literal: true
+
+require 'digest/md5'
+require 'rc4'
+
+class PDF::Reader
+
+  # Decrypts data using the RC4 algorithim defined in the PDF spec. Requires
+  # a decryption key, which is usually generated by PDF::Reader::StandardKeyBuilder
+  #
+  class Rc4SecurityHandler
+
+    def initialize(key)
+      @encrypt_key = key
+    end
+
+    ##7.6.2 General Encryption Algorithm
+    #
+    # Algorithm 1: Encryption of data using the RC4 algorithm
+    #
+    # version <=3 or (version == 4 and CFM == V2)
+    #
+    # buf - a string to decrypt
+    # ref - a PDF::Reader::Reference for the object to decrypt
+    #
+    def decrypt( buf, ref )
+      objKey = @encrypt_key.dup
+      (0..2).each { |e| objKey << (ref.id >> e*8 & 0xFF ) }
+      (0..1).each { |e| objKey << (ref.gen >> e*8 & 0xFF ) }
+      length = objKey.length < 16 ? objKey.length : 16
+      rc4 = RC4.new( Digest::MD5.digest(objKey)[0,length] )
+      rc4.decrypt(buf)
+    end
+
+  end
+end