Botan::BlockCipherModePaddingMethod Class Reference

#include <mode_pad.h>

Inheritance diagram for Botan::BlockCipherModePaddingMethod:

Public Member Functions
virtual void	add_padding (secure_vector< uint8_t > &buffer, size_t final_block_bytes, size_t block_size) const =0
virtual std::string	name () const =0
virtual size_t	unpad (const uint8_t block[], size_t len) const =0
virtual bool	valid_blocksize (size_t block_size) const =0
virtual	~BlockCipherModePaddingMethod ()=default

Static Public Member Functions
static std::unique_ptr< BlockCipherModePaddingMethod >	create (std::string_view algo_spec)

Detailed Description

Block Cipher Mode Padding Method This class is pretty limited, it cannot deal well with randomized padding methods, or any padding method that wants to add more than one block. For instance, it should be possible to define cipher text stealing mode as simply a padding mode for CBC, which happens to consume the last two block (and requires use of the block cipher).

Definition at line 26 of file mode_pad.h.

Constructor & Destructor Documentation

~BlockCipherModePaddingMethod()

virtual Botan::BlockCipherModePaddingMethod::~BlockCipherModePaddingMethod ( )

virtualdefault

virtual destructor

Member Function Documentation

add_padding()

virtual void Botan::BlockCipherModePaddingMethod::add_padding ( secure_vector< uint8_t > & buffer, size_t final_block_bytes, size_t block_size ) const

pure virtual

Add padding bytes to buffer.

Parameters

buffer	data to pad
final_block_bytes	size of the final block in bytes
block_size	size of each block in bytes

Implemented in Botan::Null_Padding, Botan::PKCS7_Padding, Botan::ANSI_X923_Padding, Botan::OneAndZeros_Padding, and Botan::ESP_Padding.

create()

std::unique_ptr< BlockCipherModePaddingMethod > Botan::BlockCipherModePaddingMethod::create ( std::string_view algo_spec )

static

Get a block cipher padding mode by name (eg "NoPadding" or "PKCS7")

Parameters

algo_spec

block cipher padding mode name

Get a block cipher padding method by name

Definition at line 19 of file mode_pad.cpp.

                                                                                                         {
   if(algo_spec == "NoPadding") {
      return std::make_unique<Null_Padding>();
   }
 
   if(algo_spec == "PKCS7") {
      return std::make_unique<PKCS7_Padding>();
   }
 
   if(algo_spec == "OneAndZeros") {
      return std::make_unique<OneAndZeros_Padding>();
   }
 
   if(algo_spec == "X9.23") {
      return std::make_unique<ANSI_X923_Padding>();
   }
 
   if(algo_spec == "ESP") {
      return std::make_unique<ESP_Padding>();
   }
 
   return nullptr;
}

Referenced by Botan::Cipher_Mode::create().

name()

virtual std::string Botan::BlockCipherModePaddingMethod::name ( ) const

pure virtual

Returns

name of the mode

Implemented in Botan::PKCS7_Padding, Botan::ANSI_X923_Padding, Botan::OneAndZeros_Padding, Botan::ESP_Padding, and Botan::Null_Padding.

unpad()

virtual size_t Botan::BlockCipherModePaddingMethod::unpad ( const uint8_t block[], size_t len ) const

pure virtual

Remove padding bytes from block

Parameters

block	the last block
len	the size of the block in bytes

Returns

number of data bytes, or if the padding is invalid returns len

Implemented in Botan::Null_Padding, Botan::PKCS7_Padding, Botan::ANSI_X923_Padding, Botan::OneAndZeros_Padding, and Botan::ESP_Padding.

valid_blocksize()

virtual bool Botan::BlockCipherModePaddingMethod::valid_blocksize ( size_t block_size ) const

pure virtual

Parameters

block_size

of the cipher

Returns

valid block size for this padding mode

Implemented in Botan::PKCS7_Padding, Botan::ANSI_X923_Padding, Botan::OneAndZeros_Padding, Botan::ESP_Padding, and Botan::Null_Padding.

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The documentation for this class was generated from the following files:

• src/lib/modes/mode_pad/mode_pad.h
• src/lib/modes/mode_pad/mode_pad.cpp