Unpacked OpenID gem. #699

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@2437 e93f8b46-1217-0410-a6f0-8f06a7374b81

vendor/gems/ruby-openid-2.1.4/lib/hmac/hmac.rb

@@ -0,0 +1,112 @@
+# Copyright (C) 2001  Daiki Ueno <ueno@unixuser.org>
+# This library is distributed under the terms of the Ruby license.
+
+# This module provides common interface to HMAC engines.
+# HMAC standard is documented in RFC 2104:
+#
+#   H. Krawczyk et al., "HMAC: Keyed-Hashing for Message Authentication",
+#   RFC 2104, February 1997
+#
+# These APIs are inspired by JCE 1.2's javax.crypto.Mac interface.
+#
+#   <URL:http://java.sun.com/security/JCE1.2/spec/apidoc/javax/crypto/Mac.html>
+
+module HMAC
+  class Base
+    def initialize(algorithm, block_size, output_length, key)
+      @algorithm = algorithm
+      @block_size = block_size
+      @output_length = output_length
+      @status = STATUS_UNDEFINED
+      @key_xor_ipad = ''
+      @key_xor_opad = ''
+      set_key(key) unless key.nil?
+    end
+
+    private
+    def check_status
+      unless @status == STATUS_INITIALIZED
+	raise RuntimeError,
+	  "The underlying hash algorithm has not yet been initialized."
+      end
+    end
+
+    public
+    def set_key(key)
+      # If key is longer than the block size, apply hash function
+      # to key and use the result as a real key.
+      key = @algorithm.digest(key) if key.size > @block_size
+      key_xor_ipad = "\x36" * @block_size
+      key_xor_opad = "\x5C" * @block_size
+      for i in 0 .. key.size - 1
+	key_xor_ipad[i] ^= key[i]
+	key_xor_opad[i] ^= key[i]
+      end
+      @key_xor_ipad = key_xor_ipad
+      @key_xor_opad = key_xor_opad
+      @md = @algorithm.new
+      @status = STATUS_INITIALIZED
+    end
+
+    def reset_key
+      @key_xor_ipad.gsub!(/./, '?')
+      @key_xor_opad.gsub!(/./, '?')
+      @key_xor_ipad[0..-1] = ''
+      @key_xor_opad[0..-1] = ''
+      @status = STATUS_UNDEFINED
+    end
+
+    def update(text)
+      check_status
+      # perform inner H
+      md = @algorithm.new
+      md.update(@key_xor_ipad)
+      md.update(text)
+      str = md.digest
+      # perform outer H
+      md = @algorithm.new
+      md.update(@key_xor_opad)
+      md.update(str)
+      @md = md
+    end
+    alias << update
+
+    def digest
+      check_status
+      @md.digest
+    end
+
+    def hexdigest
+      check_status
+      @md.hexdigest
+    end
+    alias to_s hexdigest
+
+    # These two class methods below are safer than using above
+    # instance methods combinatorially because an instance will have
+    # held a key even if it's no longer in use.
+    def Base.digest(key, text)
+      begin
+	hmac = self.new(key)
+	hmac.update(text)
+	hmac.digest
+      ensure
+	hmac.reset_key
+      end
+    end
+
+    def Base.hexdigest(key, text)
+      begin
+	hmac = self.new(key)
+	hmac.update(text)
+	hmac.hexdigest
+      ensure
+	hmac.reset_key
+      end
+    end
+
+    private_class_method :new, :digest, :hexdigest
+  end
+
+  STATUS_UNDEFINED, STATUS_INITIALIZED = 0, 1
+end