README.md

Main

Forked From : https://github.com/SergeyBel/AES

This fork was optimized and used by my file encryption/decryption program.

This header only library provides AES encryption and decryption algorithms, it has a portable C++ implementation and you can also activate and use the code that utilizes the AES-NI instructions.

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Compilation Note: This is a header only library, you only need to include the "Krypt.hpp", no need to compile the library first, and there's no need to add/link the .cpp files of the library to your compilation flag, see the example below.

To get the peak performance of this portable library compile it with the flags -O3 -march=native

If your system supports AES-NI instructions, just add the option -D USE_AESNI -maes in compilation to boost the performance.

sample program:

/*    sample.cpp    */
#include <iostream>
#include "src/Krypt.hpp"
 
using namespace Krypt;
 
int main()
{
    unsigned char plain[] = {
        0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
        0x88, 0x99, 0xaa, 0xbb
    };
 
    // if you want to use AES192 or AES256, just increase the size of the key to
    // 24 or 32... the AES class will automatically detect it, it will aslo throw
    // an error if the key size is not 16,24 or 32
    unsigned char aes128key[16] = {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
        0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
    };
 
    Mode::ECB<BlockCipher::AES,Padding::ANSI_X9_23> krypt(aes128key,sizeof(aes128key));
 
    ByteArray cipher  = krypt.encrypt(plain,sizeof(plain));
    ByteArray recover = krypt.decrypt(cipher.array,cipher.length);
}

compile with [pure c/c++ code] g++ -o sample.exe sample.cpp -O3 -march=native

comple with [AES-NI] g++ -o sample.exe sample.cpp -D USE_AESNI -maes -O3 -march=native

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The Krypt namespace contains the following :

sub-namespace	sub-namespace classes
BlockCipher	AES
Padding	ZeroNulls, ANSI_X9_23, ISO_IEC_7816_4, PKCS_5_7
Mode	ECB, CBC, CFB

Methods of the Classes inside the Mode namespace

• encrypt()
• decrypt()

Methods of the Classes inside the BlockCipher namespace

• EncryptBlock()
• DecryptBlock()

Methods of the Classes inside the Padding namespace

• AddPadding()
• RemovePadding()

The ByteArray class is used to hold the output of encrypt()/decrypt() methods of the Mode classes, and the output of AddPadding()/RemovePadding() methods of the Padding classes... ByteArray methods are listed below :

• length - returns the size of the byte array
• array - returns the byte array pointer[Krypt::Bytes* or unsigned char*]
• detach() - returns the byte array pointer[Krypt::Bytes* or unsigned char*], that pointer is then dettached to the instance of the ByteArray
• operator<< - an overload for the left-shift operator
• operator>> - an overload for the right-shift operator
• operator[] - an overload for the bracket operator, use for indexing the array