diff --git a/lib/openssl/hmac.rb b/lib/openssl/hmac.rb
index 3d442761..f80174e9 100644
--- a/lib/openssl/hmac.rb
+++ b/lib/openssl/hmac.rb
@@ -9,5 +9,70 @@ def ==(other)
 
       OpenSSL.fixed_length_secure_compare(self.digest, other.digest)
     end
+
+    # :call-seq:
+    #    hmac.base64digest -> string
+    #
+    # Returns the authentication code an a Base64-encoded string.
+    def base64digest
+      [digest].pack("m0")
+    end
+
+    class << self
+      # :call-seq:
+      #    HMAC.digest(digest, key, data) -> aString
+      #
+      # Returns the authentication code as a binary string. The _digest_ parameter
+      # specifies the digest algorithm to use. This may be a String representing
+      # the algorithm name or an instance of OpenSSL::Digest.
+      #
+      # === Example
+      #  key = 'key'
+      #  data = 'The quick brown fox jumps over the lazy dog'
+      #
+      #  hmac = OpenSSL::HMAC.digest('SHA1', key, data)
+      #  #=> "\xDE|\x9B\x85\xB8\xB7\x8A\xA6\xBC\x8Az6\xF7\n\x90p\x1C\x9D\xB4\xD9"
+      def digest(digest, key, data)
+       hmac = new(key, digest)
+       hmac << data
+       hmac.digest
+      end unless method_defined?(:digest) # JRuby
+
+      # :call-seq:
+      #    HMAC.hexdigest(digest, key, data) -> aString
+      #
+      # Returns the authentication code as a hex-encoded string. The _digest_
+      # parameter specifies the digest algorithm to use. This may be a String
+      # representing the algorithm name or an instance of OpenSSL::Digest.
+      #
+      # === Example
+      #  key = 'key'
+      #  data = 'The quick brown fox jumps over the lazy dog'
+      #
+      #  hmac = OpenSSL::HMAC.hexdigest('SHA1', key, data)
+      #  #=> "de7c9b85b8b78aa6bc8a7a36f70a90701c9db4d9"
+      def hexdigest(digest, key, data)
+       hmac = new(key, digest)
+       hmac << data
+       hmac.hexdigest
+      end unless method_defined?(:hexdigest) # JRuby
+
+      # :call-seq:
+      #    HMAC.base64digest(digest, key, data) -> aString
+      #
+      # Returns the authentication code as a Base64-encoded string. The _digest_
+      # parameter specifies the digest algorithm to use. This may be a String
+      # representing the algorithm name or an instance of OpenSSL::Digest.
+      #
+      # === Example
+      #  key = 'key'
+      #  data = 'The quick brown fox jumps over the lazy dog'
+      #
+      #  hmac = OpenSSL::HMAC.base64digest('SHA1', key, data)
+      #  #=> "3nybhbi3iqa8ino29wqQcBydtNk="
+      def base64digest(digest, key, data)
+        [digest(digest, key, data)].pack("m0")
+      end
+    end
   end
 end