lib/lockbox/padding.rb in lockbox-0.3.3 vs lib/lockbox/padding.rb in lockbox-0.3.4

@@ -1,20 +1,28 @@
 module Lockbox
   module Padding
     PAD_FIRST_BYTE = "\x80".b
     PAD_ZERO_BYTE = "\x00".b
 
+    def pad(str, **options)
+      pad!(str.dup, **options)
+    end
+
+    def unpad(str, **options)
+      unpad!(str.dup, **options)
+    end
+
     # ISO/IEC 7816-4
     # same as Libsodium
     # https://libsodium.gitbook.io/doc/padding
     # apply prior to encryption
     # note: current implementation does not
     # try to minimize side channels
-    def pad(str, size: 16)
+    def pad!(str, size: 16)
       raise ArgumentError, "Invalid size" if size < 1
 
-      str = str.dup.force_encoding(Encoding::BINARY)
+      str.force_encoding(Encoding::BINARY)
 
       pad_length = size - 1
       pad_length -= str.bytesize % size
 
       str << PAD_FIRST_BYTE
@@ -25,23 +33,22 @@
       str
     end
 
     # note: current implementation does not
     # try to minimize side channels
-    def unpad(str, size: 16)
+    def unpad!(str, size: 16)
       raise ArgumentError, "Invalid size" if size < 1
 
-      if str.encoding != Encoding::BINARY
-        str = str.dup.force_encoding(Encoding::BINARY)
-      end
+      str.force_encoding(Encoding::BINARY)
 
       i = 1
       while i <= size
         case str[-i]
         when PAD_ZERO_BYTE
           i += 1
         when PAD_FIRST_BYTE
-          return str[0..-(i + 1)]
+          str.slice!(-i..-1)
+          return str
         else
           break
         end
       end