Move mode padding schemes to modes/mode_pad module

3 files changed, 214 insertions, 0 deletions

diff --git a/src/modes/mode_pad/mode_pad.cpp b/src/modes/mode_pad/mode_pad.cpp
new file mode 100644
index 000000000..3a07afcb4
--- /dev/null
+++ b/src/modes/mode_pad/mode_pad.cpp
@@ -0,0 +1,125 @@
+/*************************************************
+* CBC Padding Methods Source File                *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/mode_pad.h>
+#include <botan/util.h>
+
+namespace Botan {
+
+/*************************************************
+* Default amount of padding                      *
+*************************************************/
+u32bit BlockCipherModePaddingMethod::pad_bytes(u32bit bs, u32bit pos) const
+   {
+   return (bs - pos);
+   }
+
+/*************************************************
+* Pad with PKCS #7 Method                        *
+*************************************************/
+void PKCS7_Padding::pad(byte block[], u32bit size, u32bit position) const
+   {
+   for(u32bit j = 0; j != size; ++j)
+      block[j] = (size-position);
+   }
+
+/*************************************************
+* Unpad with PKCS #7 Method                      *
+*************************************************/
+u32bit PKCS7_Padding::unpad(const byte block[], u32bit size) const
+   {
+   u32bit position = block[size-1];
+   if(position > size)
+      throw Decoding_Error(name());
+   for(u32bit j = size-position; j != size-1; ++j)
+      if(block[j] != position)
+         throw Decoding_Error(name());
+   return (size-position);
+   }
+
+/*************************************************
+* Query if the size is valid for this method     *
+*************************************************/
+bool PKCS7_Padding::valid_blocksize(u32bit size) const
+   {
+   if(size > 0 && size < 256)
+      return true;
+   else
+      return false;
+   }
+
+/*************************************************
+* Pad with ANSI X9.23 Method                     *
+*************************************************/
+void ANSI_X923_Padding::pad(byte block[], u32bit size, u32bit position) const
+   {
+   for(u32bit j = 0; j != size-position; ++j)
+      block[j] = 0;
+   block[size-position-1] = (size-position);
+   }
+
+/*************************************************
+* Unpad with ANSI X9.23 Method                   *
+*************************************************/
+u32bit ANSI_X923_Padding::unpad(const byte block[], u32bit size) const
+   {
+   u32bit position = block[size-1];
+   if(position > size)
+      throw Decoding_Error(name());
+   for(u32bit j = size-position; j != size-1; ++j)
+      if(block[j] != 0)
+         throw Decoding_Error(name());
+   return (size-position);
+   }
+
+/*************************************************
+* Query if the size is valid for this method     *
+*************************************************/
+bool ANSI_X923_Padding::valid_blocksize(u32bit size) const
+   {
+   if(size > 0 && size < 256)
+      return true;
+   else
+      return false;
+   }
+
+/*************************************************
+* Pad with One and Zeros Method                  *
+*************************************************/
+void OneAndZeros_Padding::pad(byte block[], u32bit size, u32bit) const
+   {
+   block[0] = 0x80;
+   for(u32bit j = 1; j != size; ++j)
+      block[j] = 0x00;
+   }
+
+/*************************************************
+* Unpad with One and Zeros Method                *
+*************************************************/
+u32bit OneAndZeros_Padding::unpad(const byte block[], u32bit size) const
+   {
+   while(size)
+      {
+      if(block[size-1] == 0x80)
+         break;
+      if(block[size-1] != 0x00)
+         throw Decoding_Error(name());
+      size--;
+      }
+   if(!size)
+      throw Decoding_Error(name());
+   return (size-1);
+   }
+
+/*************************************************
+* Query if the size is valid for this method     *
+*************************************************/
+bool OneAndZeros_Padding::valid_blocksize(u32bit size) const
+   {
+   if(size) return true;
+   else     return false;
+   }
+
+}
diff --git a/src/modes/mode_pad/mode_pad.h b/src/modes/mode_pad/mode_pad.h
new file mode 100644
index 000000000..4041efcdc
--- /dev/null
+++ b/src/modes/mode_pad/mode_pad.h
@@ -0,0 +1,79 @@
+/*************************************************
+* CBC Padding Methods Header File                *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#ifndef BOTAN_CBC_PADDING_H__
+#define BOTAN_CBC_PADDING_H__
+
+#include <botan/base.h>
+#include <string>
+
+namespace Botan {
+
+/*************************************************
+* Block Cipher Mode Padding Method               *
+*************************************************/
+class BOTAN_DLL BlockCipherModePaddingMethod
+   {
+   public:
+      virtual void pad(byte[], u32bit, u32bit) const = 0;
+      virtual u32bit unpad(const byte[], u32bit) const = 0;
+      virtual u32bit pad_bytes(u32bit, u32bit) const;
+      virtual bool valid_blocksize(u32bit) const = 0;
+      virtual std::string name() const = 0;
+      virtual ~BlockCipherModePaddingMethod() {}
+   };
+
+/*************************************************
+* PKCS#7 Padding                                 *
+*************************************************/
+class BOTAN_DLL PKCS7_Padding : public BlockCipherModePaddingMethod
+   {
+   public:
+      void pad(byte[], u32bit, u32bit) const;
+      u32bit unpad(const byte[], u32bit) const;
+      bool valid_blocksize(u32bit) const;
+      std::string name() const { return "PKCS7"; }
+   };
+
+/*************************************************
+* ANSI X9.23 Padding                             *
+*************************************************/
+class BOTAN_DLL ANSI_X923_Padding : public BlockCipherModePaddingMethod
+   {
+   public:
+      void pad(byte[], u32bit, u32bit) const;
+      u32bit unpad(const byte[], u32bit) const;
+      bool valid_blocksize(u32bit) const;
+      std::string name() const { return "X9.23"; }
+   };
+
+/*************************************************
+* One And Zeros Padding                          *
+*************************************************/
+class BOTAN_DLL OneAndZeros_Padding : public BlockCipherModePaddingMethod
+   {
+   public:
+      void pad(byte[], u32bit, u32bit) const;
+      u32bit unpad(const byte[], u32bit) const;
+      bool valid_blocksize(u32bit) const;
+      std::string name() const { return "OneAndZeros"; }
+   };
+
+/*************************************************
+* Null Padding                                   *
+*************************************************/
+class BOTAN_DLL Null_Padding : public BlockCipherModePaddingMethod
+   {
+   public:
+      void pad(byte[], u32bit, u32bit) const { return; }
+      u32bit unpad(const byte[], u32bit size) const { return size; }
+      u32bit pad_bytes(u32bit, u32bit) const { return 0; }
+      bool valid_blocksize(u32bit) const { return true; }
+      std::string name() const { return "NoPadding"; }
+   };
+
+}
+
+#endif
diff --git a/src/modes/mode_pad/modinfo.txt b/src/modes/mode_pad/modinfo.txt
new file mode 100644
index 000000000..f22cf7411
--- /dev/null
+++ b/src/modes/mode_pad/modinfo.txt
@@ -0,0 +1,10 @@
+realname "Cipher Mode Padding Method"
+
+define CIPHER_MODE_PADDING
+
+load_on auto
+
+<add>
+mode_pad.cpp
+mode_pad.h
+</add>