Bonjour,

J'ai depuis peut un petit projet en tête qui utilise l'algorithme AES. J'aimerai utiliser ma propre implémentation de cet algorithme sans utiliser cipher pour java ou encore openssl en c++.

Cependant le chiffrement de 3Go prend en moyenne 1.20 min via l'implémentation en c++ contre 40 sec en java avec cipher.

J'utilise comme base cet implémentation : http://comp.ist.utl.pt/ec-csc/Code/C...ES_Encrypt.cpp

Code : Sélectionner tout - Visualiser dans une fenêtre à part
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// Include stdio.h for standard input/output.
// Used for giving output to the screen.
#include<stdio.h>
#include<iostream>
#include<fstream>
#include<stdlib.h>
 
// The number of columns comprising a state in AES. This is a constant in AES. Value=4
#define Nb 4
 
// The number of rounds in AES Cipher. It is simply initiated to zero. The actual value is recieved in the program.
int Nr=0;
 
// The number of 32 bit words in the key. It is simply initiated to zero. The actual value is recieved in the program.
int Nk=0;
 
// in - it is the array that holds the plain text to be encrypted.
// out - it is the array that holds the key for encryption.
// state - the array that holds the intermediate results during encryption.
unsigned char in[16], out[16], state[4][4];
 
// The array that stores the round keys.
unsigned char RoundKey[240];
 
// The Key input to the AES Program
unsigned char Key[32];
 
int sbox[256] =   {
    //0     1    2      3     4    5     6     7      8    9     A      B    C     D     E     F
    0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, //0
    0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, //1
    0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, //2
    0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, //3
    0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, //4
    0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, //5
    0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, //6
    0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, //7
    0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, //8
    0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, //9
    0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, //A
    0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, //B
    0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, //C
    0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, //D
    0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, //E
    0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; //F
 
int xtimeTab[]={ 0x0 ,
    0x2 , 0x4 , 0x6 , 0x8 , 0xa , 0xc , 0xe , 0x10 , 0x12 , 0x14 , 0x16 , 0x18 , 0x1a , 0x1c , 0x1e ,
    0x20 , 0x22 , 0x24 , 0x26 , 0x28 , 0x2a , 0x2c , 0x2e , 0x30 , 0x32 , 0x34 , 0x36 , 0x38 , 0x3a , 0x3c ,
    0x3e , 0x40 , 0x42 , 0x44 , 0x46 , 0x48 , 0x4a , 0x4c , 0x4e , 0x50 , 0x52 , 0x54 , 0x56 , 0x58 , 0x5a ,
    0x5c , 0x5e , 0x60 , 0x62 , 0x64 , 0x66 , 0x68 , 0x6a , 0x6c , 0x6e , 0x70 , 0x72 , 0x74 , 0x76 , 0x78 ,
    0x7a , 0x7c , 0x7e , 0x80 , 0x82 , 0x84 , 0x86 , 0x88 , 0x8a , 0x8c , 0x8e , 0x90 , 0x92 , 0x94 , 0x96 ,
    0x98 , 0x9a , 0x9c , 0x9e , 0xa0 , 0xa2 , 0xa4 , 0xa6 , 0xa8 , 0xaa , 0xac , 0xae , 0xb0 , 0xb2 , 0xb4 ,
    0xb6 , 0xb8 , 0xba , 0xbc , 0xbe , 0xc0 , 0xc2 , 0xc4 , 0xc6 , 0xc8 , 0xca , 0xcc , 0xce , 0xd0 , 0xd2 ,
    0xd4 , 0xd6 , 0xd8 , 0xda , 0xdc , 0xde , 0xe0 , 0xe2 , 0xe4 , 0xe6 , 0xe8 , 0xea , 0xec , 0xee , 0xf0 ,
    0xf2 , 0xf4 , 0xf6 , 0xf8 , 0xfa , 0xfc , 0xfe , 0x1b , 0x19 , 0x1f , 0x1d , 0x13 , 0x11 , 0x17 , 0x15 ,
    0xb , 0x9 , 0xf , 0xd , 0x3 , 0x1 , 0x7 , 0x5 , 0x3b , 0x39 , 0x3f , 0x3d , 0x33 , 0x31 , 0x37 ,
    0x35 , 0x2b , 0x29 , 0x2f , 0x2d , 0x23 , 0x21 , 0x27 , 0x25 , 0x5b , 0x59 , 0x5f , 0x5d , 0x53 , 0x51 ,
    0x57 , 0x55 , 0x4b , 0x49 , 0x4f , 0x4d , 0x43 , 0x41 , 0x47 , 0x45 , 0x7b , 0x79 , 0x7f , 0x7d , 0x73 ,
    0x71 , 0x77 , 0x75 , 0x6b , 0x69 , 0x6f , 0x6d , 0x63 , 0x61 , 0x67 , 0x65 , 0x9b , 0x99 , 0x9f , 0x9d ,
    0x93 , 0x91 , 0x97 , 0x95 , 0x8b , 0x89 , 0x8f , 0x8d , 0x83 , 0x81 , 0x87 , 0x85 , 0xbb , 0xb9 , 0xbf ,
    0xbd , 0xb3 , 0xb1 , 0xb7 , 0xb5 , 0xab , 0xa9 , 0xaf , 0xad , 0xa3 , 0xa1 , 0xa7 , 0xa5 , 0xdb , 0xd9 ,
    0xdf , 0xdd , 0xd3 , 0xd1 , 0xd7 , 0xd5 , 0xcb , 0xc9 , 0xcf , 0xcd , 0xc3 , 0xc1 , 0xc7 , 0xc5 , 0xfb ,
    0xf9 , 0xff , 0xfd , 0xf3 , 0xf1 , 0xf7 , 0xf5 , 0xeb , 0xe9 , 0xef , 0xed , 0xe3 , 0xe1 , 0xe7 , 0xe5 };
 
// The round constant word array, Rcon[i], contains the values given by
// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(28)
// Note that i starts at 1, not 0).
int Rcon[255] = {
	0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
	0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
	0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
	0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
	0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
	0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
	0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
	0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
	0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
	0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
	0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
	0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
	0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
	0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
	0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
	0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb  };
 
// This function produces Nb(Nr+1) round keys. The round keys are used in each round to encrypt the states.
void KeyExpansion(){
	int i,j;
	unsigned char temp[4],k;
 
	// The first round key is the key itself.
	for(i=0;i<Nk;i++)
	{
		RoundKey[i*4]=Key[i*4];
		RoundKey[i*4+1]=Key[i*4+1];
		RoundKey[i*4+2]=Key[i*4+2];
		RoundKey[i*4+3]=Key[i*4+3];
	}
 
	// All other round keys are found from the previous round keys.
	while (i < (Nb * (Nr+1))){
        for(j=0;j<4;j++)
            temp[j]=RoundKey[(i-1) * 4 + j];
 
        if (i % Nk == 0){
            // Function RotWord()
            {
                k = temp[0];
                temp[0] = temp[1];
                temp[1] = temp[2];
                temp[2] = temp[3];
                temp[3] = k;
            }
 
            // Function Subword()
            {
                temp[0]=sbox[temp[0]];
                temp[1]=sbox[temp[1]];
                temp[2]=sbox[temp[2]];
                temp[3]=sbox[temp[3]];
            }
 
            temp[0] ^= Rcon[i/Nk];
        }
        else if (Nk > 6 && i % Nk == 4){
            // Function Subword()
            {
                temp[0]=sbox[temp[0]];
                temp[1]=sbox[temp[1]];
                temp[2]=sbox[temp[2]];
                temp[3]=sbox[temp[3]];
            }
        }
        RoundKey[i*4] = RoundKey[(i-Nk)*4] ^ temp[0];
        RoundKey[i*4+1] = RoundKey[(i-Nk)*4+1] ^ temp[1];
        RoundKey[i*4+2] = RoundKey[(i-Nk)*4+2] ^ temp[2];
        RoundKey[i*4+3] = RoundKey[(i-Nk)*4+3] ^ temp[3];
        ++i;
	}
}
 
#define NB4 Nb * 4
 
void AddRoundKey(int round){
	for(int i=0; i<4; ++i)
		for(int j=0; j<4; ++j)
			state[j][i] ^= RoundKey[round * NB4 + i * Nb + j];
}
 
void SubBytes(){
	for(int i=0; i<4; ++i)
        for(int j=0; j<4; ++j)
			state[i][j] = sbox[state[i][j]];
}
 
void ShiftRows(){
	unsigned char temp;
 
	// Rotate first row 1 columns to left
	temp=state[1][0];
	state[1][0]=state[1][1];
	state[1][1]=state[1][2];
	state[1][2]=state[1][3];
	state[1][3]=temp;
 
	// Rotate second row 2 columns to left
	temp=state[2][0];
	state[2][0]=state[2][2];
	state[2][2]=temp;
 
	temp=state[2][1];
	state[2][1]=state[2][3];
	state[2][3]=temp;
 
	// Rotate third row 3 columns to left
	temp=state[3][0];
	state[3][0]=state[3][3];
	state[3][3]=state[3][2];
	state[3][2]=state[3][1];
	state[3][1]=temp;
}
 
// xtime is a macro that finds the product of {02} and the argument to xtime modulo {1b}
#define xtime(x)   ((x<<1) ^ (((x>>7) & 1) * 0x1b))
 
// MixColumns function mixes the columns of the state matrix
void MixColumns(){
	unsigned char Tmp,Tm,t;
	for(int i = 0; i < 4; ++i){
		t=state[0][i];
		Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ;
 
        state[0][i] ^= xtimeTab[state[0][i] ^ state[1][i]] ^ Tmp ;
        state[1][i] ^= xtimeTab[state[1][i] ^ state[2][i]] ^ Tmp ;
        state[2][i] ^= xtimeTab[state[2][i] ^ state[3][i]] ^ Tmp ;
        state[3][i] ^= xtimeTab[state[3][i] ^ t] ^ Tmp ;
	}
}
int cmpt = 0;
 
// Cipher is the main function that encrypts the PlainText.
void Cipher(){
	int i,j,round;
 
	//Copy the input PlainText to state array.
	for(i=0;i<4;++i)
		for(j=0;j<4;++j)
			state[j][i] = in[i*4 + j];
 
	// Add the First round key to the state before starting the rounds.
	AddRoundKey(0);
 
	// There will be Nr rounds.
	// The first Nr-1 rounds are identical.
	// These Nr-1 rounds are executed in the loop below.
	for(round = 1; round < Nr; ++round){
		SubBytes();
		ShiftRows();
		MixColumns();
		AddRoundKey(round);
	}
 
	// The last round is given below.
	// The MixColumns function is not here in the last round.
	SubBytes();
	ShiftRows();
	AddRoundKey(Nr);
 
	// The encryption process is over.
	// Copy the state array to output array.
	for(i=0; i<4; ++i)
		for(j=0; j<4; ++j)
			out[i*4+j] = state[j][i];
    ++cmpt;
}
 
int main(){
	int i;
    /*unsigned char a;
    printf("int xtimeTab[]={ ");
    for (i = 0; i < 256; ++i){
        a = xtime(i);
        printf("0x%x , ",a);
        if(i%15 == 0)
            printf("\n");
    }
    exit(1);*/
    Nr = 128;
	// Calculate Nk and Nr from the recieved value.
	Nk = Nr / 32;
	Nr = Nk + 6;
 
 
 
    // Part 1 is for demonstrative purpose. The key and plaintext are given in the program itself.
    // 	Part 1: ********************************************************
 
	// The array temp stores the key.
	// The array temp2 stores the plaintext.
	unsigned char temp[32] = {0x00  ,0x01  ,0x02  ,0x03  ,0x04  ,0x05  ,0x06  ,0x07  ,0x08  ,0x09  ,0x0a  ,0x0b  ,0x0c  ,0x0d  ,0x0e  ,0x0f};
	unsigned char temp2[32]= {0x00  ,0x11  ,0x22  ,0x33  ,0x44  ,0x55  ,0x66  ,0x77  ,0x88  ,0x99  ,0xaa  ,0xbb  ,0xcc  ,0xdd  ,0xee  ,0xff};
 
	// Copy the Key and PlainText
	for(i=0;i<Nk*4;i++){
		Key[i]=temp[i];
		in[i]=temp2[i];
	}
 
 
	// The KeyExpansion routine must be called before encryption.
	KeyExpansion();
 
	// The next function call encrypts the PlainText with the Key using AES algorithm.
    for (i = 0; i < 200000000; ++i)// 200000000*16 octet => 3051,75781 Mo
        Cipher();
 
    printf("%d\n",cmpt);
	// Output the encrypted text.
	printf("\nText after encryption:\n");
	for(i=0;i<Nb*4;i++){
		printf("%02x ",out[i]);
	}
	printf("\n\n");
}
Est-ce que quelqu'un pourrait me dire comment améliorer ce code pour améliorer le temps de chiffrement ? ou s'il existe un code (de base) qui améliore ces temps ?

(le code montré chiffre un block de 16 octet, dans mon code je réitère simplement cet action autant de fois pour arriver à 3Go. (appel de la fonction Cipher() x fois)).


Merci.

Alexandre