diff options
Diffstat (limited to 'botan/src/modes/mode_pad/mode_pad.cpp')
-rw-r--r-- | botan/src/modes/mode_pad/mode_pad.cpp | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/botan/src/modes/mode_pad/mode_pad.cpp b/botan/src/modes/mode_pad/mode_pad.cpp new file mode 100644 index 0000000..b8badd7 --- /dev/null +++ b/botan/src/modes/mode_pad/mode_pad.cpp @@ -0,0 +1,128 @@ +/* +* CBC Padding Methods +* (C) 1999-2007 Jack Lloyd +* +* Distributed under the terms of the Botan license +*/ + +#include <botan/mode_pad.h> +#include <botan/exceptn.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; + } + +} |