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/*
* CBC Padding Methods
* (C) 1999-2007,2013 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/mode_pad.h>
#include <botan/exceptn.h>
namespace Botan {
/*
* Pad with PKCS #7 Method
*/
void PKCS7_Padding::add_padding(secure_vector<byte>& buffer,
size_t last_byte_pos,
size_t block_size) const
{
const byte pad_value = block_size - last_byte_pos;
for(size_t i = 0; i != pad_value; ++i)
buffer.push_back(pad_value);
}
/*
* Unpad with PKCS #7 Method
*/
size_t PKCS7_Padding::unpad(const byte block[], size_t size) const
{
size_t position = block[size-1];
if(position > size)
throw Decoding_Error("Bad padding in " + name());
for(size_t j = size-position; j != size-1; ++j)
if(block[j] != position)
throw Decoding_Error("Bad padding in " + name());
return (size-position);
}
/*
* Pad with ANSI X9.23 Method
*/
void ANSI_X923_Padding::add_padding(secure_vector<byte>& buffer,
size_t last_byte_pos,
size_t block_size) const
{
const byte pad_value = block_size - last_byte_pos;
for(size_t i = last_byte_pos; i < block_size; ++i)
buffer.push_back(0);
buffer.push_back(pad_value);
}
/*
* Unpad with ANSI X9.23 Method
*/
size_t ANSI_X923_Padding::unpad(const byte block[], size_t size) const
{
size_t position = block[size-1];
if(position > size)
throw Decoding_Error(name());
for(size_t j = size-position; j != size-1; ++j)
if(block[j] != 0)
throw Decoding_Error(name());
return (size-position);
}
/*
* Pad with One and Zeros Method
*/
void OneAndZeros_Padding::add_padding(secure_vector<byte>& buffer,
size_t last_byte_pos,
size_t block_size) const
{
buffer.push_back(0x80);
for(size_t i = last_byte_pos + 1; i % block_size; ++i)
buffer.push_back(0x00);
}
/*
* Unpad with One and Zeros Method
*/
size_t OneAndZeros_Padding::unpad(const byte block[], size_t 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);
}
}
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