#ifndef QAESENCRYPTION_H
#define QAESENCRYPTION_H
#include <QObject>
#include <QByteArray>
#include <QCryptographicHash>
class QAESEncryption : public QObject
{
Q_OBJECT
public:
enum Aes {
AES_128,
AES_192,
AES_256
};
enum Mode {
ECB,
CBC,
CFB,
OFB
};
enum Padding {
ZERO,
PKCS7,
ISO
};
static QByteArray Crypt(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &rawText, const QByteArray &key,
const QByteArray &iv = NULL, QAESEncryption::Padding padding = QAESEncryption::ISO);
static QByteArray Decrypt(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &rawText, const QByteArray &key,
const QByteArray &iv = NULL, QAESEncryption::Padding padding = QAESEncryption::ISO);
static QByteArray ExpandKey(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &key);
static QByteArray RemovePadding(const QByteArray &rawText, QAESEncryption::Padding padding);
QAESEncryption(QAESEncryption::Aes level, QAESEncryption::Mode mode,
QAESEncryption::Padding padding = QAESEncryption::ISO);
QByteArray encode(const QByteArray &rawText, const QByteArray &key, const QByteArray &iv = NULL);
QByteArray decode(const QByteArray &rawText, const QByteArray &key, const QByteArray &iv = NULL);
QByteArray removePadding(const QByteArray &rawText);
QByteArray expandKey(const QByteArray &key);
signals:
public slots:
private:
int m_nb;
int m_blocklen;
int m_level;
int m_mode;
int m_nk;
int m_keyLen;
int m_nr;
int m_expandedKey;
int m_padding;
QByteArray* m_state;
struct AES256{
int nk = 8;
int keylen = 32;
int nr = 14;
int expandedKey = 240;
};
struct AES192{
int nk = 6;
int keylen = 24;
int nr = 12;
int expandedKey = 209;
};
struct AES128{
int nk = 4;
int keylen = 16;
int nr = 10;
int expandedKey = 176;
};
quint8 getSBoxValue(quint8 num){return sbox[num];}
quint8 getSBoxInvert(quint8 num){return rsbox[num];}
void addRoundKey(const quint8 round, const QByteArray expKey);
void subBytes();
void shiftRows();
void mixColumns();
void invMixColumns();
void invSubBytes();
void invShiftRows();
QByteArray getPadding(int currSize, int alignment);
QByteArray cipher(const QByteArray &expKey, const QByteArray &plainText);
QByteArray invCipher(const QByteArray &expKey, const QByteArray &plainText);
QByteArray byteXor(const QByteArray &in, const QByteArray &iv);
static quint8 sbox[256];
static quint8 rsbox[256];
static quint8 Rcon[256];
};
#endif // QAESENCRYPTION_H
/*
* Static Functions
* */
QByteArray QAESEncryption::Crypt(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &rawText,
const QByteArray &key, const QByteArray &iv, QAESEncryption::Padding padding)
{
return QAESEncryption(level, mode, padding).encode(rawText, key, iv);
}
QByteArray QAESEncryption::Decrypt(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &rawText,
const QByteArray &key, const QByteArray &iv, QAESEncryption::Padding padding)
{
return QAESEncryption(level, mode, padding).decode(rawText, key, iv);
}
QByteArray QAESEncryption::ExpandKey(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &key)
{
return QAESEncryption(level, mode).expandKey(key);
}
QByteArray QAESEncryption::RemovePadding(const QByteArray &rawText, QAESEncryption::Padding padding)
{
if (rawText.isEmpty())
return rawText;
QByteArray ret(rawText);
switch (padding)
{
case Padding::ZERO:
//Works only if the last byte of the decoded array is not zero
while (ret.at(ret.length()-1) == 0x00)
ret.remove(ret.length()-1, 1);
break;
case Padding::PKCS7:
ret.remove(ret.length() - ret.at(ret.length()-1), ret.at(ret.length()-1));
break;
case Padding::ISO:
{
// Find the last byte which is not zero
int marker_index = ret.length() - 1;
for (; marker_index >= 0; --marker_index)
{
if (ret.at(marker_index) != 0x00)
{
break;
}
}
// And check if it's the byte for marking padding
if (ret.at(marker_index) == static_cast<char>(0x80))
{
ret.truncate(marker_index);
}
break;
}
default:
//do nothing
break;
}
return ret;
}
/*
* End Static function declarations
* */
/*
* Inline Functions
* */
inline quint8 xTime(quint8 x){
return ((x<<1) ^ (((x>>7) & 1) * 0x1b));
}
inline quint8 multiply(quint8 x, quint8 y){
return (((y & 1) * x) ^ ((y>>1 & 1) * xTime(x)) ^ ((y>>2 & 1) * xTime(xTime(x))) ^ ((y>>3 & 1)
* xTime(xTime(xTime(x)))) ^ ((y>>4 & 1) * xTime(xTime(xTime(xTime(x))))));
}
/*
* End Inline functions
* */
QAESEncryption::QAESEncryption(Aes level, Mode mode,
Padding padding)
: m_nb(4), m_blocklen(16), m_level(level), m_mode(mode), m_padding(padding)
{
m_state = NULL;
switch (level)
{
case AES_128: {
AES128 aes;
m_nk = aes.nk;
m_keyLen = aes.keylen;
m_nr = aes.nr;
m_expandedKey = aes.expandedKey;
}
break;
case AES_192: {
AES192 aes;
m_nk = aes.nk;
m_keyLen = aes.keylen;
m_nr = aes.nr;
m_expandedKey = aes.expandedKey;
}
break;
case AES_256: {
AES256 aes;
m_nk = aes.nk;
m_keyLen = aes.keylen;
m_nr = aes.nr;
m_expandedKey = aes.expandedKey;
}
break;
default: {
AES128 aes;
m_nk = aes.nk;
m_keyLen = aes.keylen;
m_nr = aes.nr;
m_expandedKey = aes.expandedKey;
}
break;
}
}
QByteArray QAESEncryption::getPadding(int currSize, int alignment)
{
int size = (alignment - currSize % alignment) % alignment;
if (size == 0) return QByteArray();
switch(m_padding)
{
case Padding::ZERO:
return QByteArray(size, 0x00);
break;
case Padding::PKCS7:
return QByteArray(size,size);
break;
case Padding::ISO:
return QByteArray (size-1, 0x00).prepend(0x80);
break;
default:
return QByteArray(size, 0x00);
break;
}
return QByteArray(size, 0x00);
}
QByteArray QAESEncryption::expandKey(const QByteArray &key)
{
int i, k;
quint8 tempa[4]; // Used for the column/row operations
QByteArray roundKey(key);
// The first round key is the key itself.
// ...
// All other round keys are found from the previous round keys.
//i == Nk
for(i = m_nk; i < m_nb * (m_nr + 1); i++)
{
tempa[0] = (quint8) roundKey.at((i-1) * 4 + 0);
tempa[1] = (quint8) roundKey.at((i-1) * 4 + 1);
tempa[2] = (quint8) roundKey.at((i-1) * 4 + 2);
tempa[3] = (quint8) roundKey.at((i-1) * 4 + 3);
if (i % m_nk == 0)
{
// This function shifts the 4 bytes in a word to the left once.
// [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
// Function RotWord()
k = tempa[0];
tempa[0] = tempa[1];
tempa[1] = tempa[2];
tempa[2] = tempa[3];
tempa[3] = k;
// Function Subword()
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
tempa[0] = tempa[0] ^ Rcon[i/m_nk];
}
if (m_level == AES_256 && i % m_nk == 4)
{
// Function Subword()
tempa[0] = getSBoxValue(tempa[0]);
tempa[1] = getSBoxValue(tempa[1]);
tempa[2] = getSBoxValue(tempa[2]);
tempa[3] = getSBoxValue(tempa[3]);
}
roundKey.insert(i * 4 + 0, (quint8) roundKey.at((i - m_nk) * 4 + 0) ^ tempa[0]);
roundKey.insert(i * 4 + 1, (quint8) roundKey.at((i - m_nk) * 4 + 1) ^ tempa[1]);
roundKey.insert(i * 4 + 2, (quint8) roundKey.at((i - m_nk) * 4 + 2) ^ tempa[2]);
roundKey.insert(i * 4 + 3, (quint8) roundKey.at((i - m_nk) * 4 + 3) ^ tempa[3]);
}
return roundKey;
}
// This function adds the round key to state.
// The round key is added to the state by an XOR function.
void QAESEncryption::addRoundKey(const quint8 round, const QByteArray expKey)
{
QByteArray::iterator it = m_state->begin();
for(int i=0; i < 16; ++i)
it[i] = (quint8) it[i] ^ (quint8) expKey.at(round * m_nb * 4 + (i/4) * m_nb + (i%4));
}
// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
void QAESEncryption::subBytes()
{
QByteArray::iterator it = m_state->begin();
for(int i = 0; i < 16; i++)
it[i] = getSBoxValue((quint8) it[i]);
}
// The ShiftRows() function shifts the rows in the state to the left.
// Each row is shifted with different offset.
// Offset = Row number. So the first row is not shifted.
void QAESEncryption::shiftRows()
{
QByteArray::iterator it = m_state->begin();
quint8 temp;
//Keep in mind that QByteArray is column-driven!!
//Shift 1 to left
temp = (quint8)it[1];
it[1] = (quint8)it[5];
it[5] = (quint8)it[9];
it[9] = (quint8)it[13];
it[13] = (quint8)temp;
//Shift 2 to left
temp = (quint8)it[2];
it[2] = (quint8)it[10];
it[10] = (quint8)temp;
temp = (quint8)it[6];
it[6] = (quint8)it[14];
it[14] = (quint8)temp;
//Shift 3 to left
temp = (quint8)it[3];
it[3] = (quint8)it[15];
it[15] = (quint8)it[11];
it[11] = (quint8)it[7];
it[7] = (quint8)temp;
}
// MixColumns function mixes the columns of the state matrix
//optimized!!
void QAESEncryption::mixColumns()
{
QByteArray::iterator it = m_state->begin();
quint8 tmp, tm, t;
for(int i = 0; i < 16; i += 4){
t = (quint8)it[i];
tmp = (quint8)it[i] ^ (quint8)it[i+1] ^ (quint8)it[i+2] ^ (quint8)it[i+3] ;
tm = xTime( (quint8)it[i] ^ (quint8)it[i+1] );
it[i] = (quint8)it[i] ^ (quint8)tm ^ (quint8)tmp;
tm = xTime( (quint8)it[i+1] ^ (quint8)it[i+2]);
it[i+1] = (quint8)it[i+1] ^ (quint8)tm ^ (quint8)tmp;
tm = xTime( (quint8)it[i+2] ^ (quint8)it[i+3]);
it[i+2] =(quint8)it[i+2] ^ (quint8)tm ^ (quint8)tmp;
tm = xTime((quint8)it[i+3] ^ (quint8)t);
it[i+3] =(quint8)it[i+3] ^ (quint8)tm ^ (quint8)tmp;
}
}
// MixColumns function mixes the columns of the state matrix.
// The method used to multiply may be difficult to understand for the inexperienced.
// Please use the references to gain more information.
void QAESEncryption::invMixColumns()
{
QByteArray::iterator it = m_state->begin();
quint8 a,b,c,d;
for(int i = 0; i < 16; i+=4){
a = (quint8) it[i];
b = (quint8) it[i+1];
c = (quint8) it[i+2];
d = (quint8) it[i+3];
it[i] = (quint8) (multiply(a, 0x0e) ^ multiply(b, 0x0b) ^ multiply(c, 0x0d) ^ multiply(d, 0x09));
it[i+1] = (quint8) (multiply(a, 0x09) ^ multiply(b, 0x0e) ^ multiply(c, 0x0b) ^ multiply(d, 0x0d));
it[i+2] = (quint8) (multiply(a, 0x0d) ^ multiply(b, 0x09) ^ multiply(c, 0x0e) ^ multiply(d, 0x0b));
it[i+3] = (quint8) (multiply(a, 0x0b) ^ multiply(b, 0x0d) ^ multiply(c, 0x09) ^ multiply(d, 0x0e));
}
}
// The SubBytes Function Substitutes the values in the
// state matrix with values in an S-box.
void QAESEncryption::invSubBytes()
{
QByteArray::iterator it = m_state->begin();
for(int i = 0; i < 16; ++i)
it[i] = getSBoxInvert((quint8) it[i]);
}
void QAESEncryption::invShiftRows()
{
QByteArray::iterator it = m_state->begin();
quint8 temp;
//Keep in mind that QByteArray is column-driven!!
//Shift 1 to right
temp = (quint8)it[13];
it[13] = (quint8)it[9];
it[9] = (quint8)it[5];
it[5] = (quint8)it[1];
it[1] = (quint8)temp;
//Shift 2
temp = (quint8)it[10];
it[10] = (quint8)it[2];
it[2] = (quint8)temp;
temp = (quint8)it[14];
it[14] = (quint8)it[6];
it[6] = (quint8)temp;
//Shift 3
temp = (quint8)it[15];
it[15] = (quint8)it[3];
it[3] = (quint8)it[7];
it[7] = (quint8)it[11];
it[11] = (quint8)temp;
}
QByteArray QAESEncryption::byteXor(const QByteArray &a, const QByteArray &b)
{
QByteArray::const_iterator it_a = a.begin();
QByteArray::const_iterator it_b = b.begin();
QByteArray ret;
//for(int i = 0; i < m_blocklen; i++)
for(int i = 0; i < std::min(a.size(), b.size()); i++)
ret.insert(i,it_a[i] ^ it_b[i]);
return ret;
}
// Cipher is the main function that encrypts the PlainText.
QByteArray QAESEncryption::cipher(const QByteArray &expKey, const QByteArray &in)
{
//m_state is the input buffer...
QByteArray output(in);
m_state = &output;
// Add the First round key to the state before starting the rounds.
addRoundKey(0, expKey);
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for(quint8 round = 1; round < m_nr; ++round){
subBytes();
shiftRows();
mixColumns();
addRoundKey(round, expKey);
}
// The last round is given below.
// The MixColumns function is not here in the last round.
subBytes();
shiftRows();
addRoundKey(m_nr, expKey);
return output;
}
QByteArray QAESEncryption::invCipher(const QByteArray &expKey, const QByteArray &in)
{
//m_state is the input buffer.... handle it!
QByteArray output(in);
m_state = &output;
// Add the First round key to the state before starting the rounds.
addRoundKey(m_nr, expKey);
// There will be Nr rounds.
// The first Nr-1 rounds are identical.
// These Nr-1 rounds are executed in the loop below.
for(quint8 round=m_nr-1; round>0 ; round--){
invShiftRows();
invSubBytes();
addRoundKey(round, expKey);
invMixColumns();
}
// The last round is given below.
// The MixColumns function is not here in the last round.
invShiftRows();
invSubBytes();
addRoundKey(0, expKey);
return output;
}
QByteArray QAESEncryption::encode(const QByteArray &rawText, const QByteArray &key, const QByteArray &iv)
{
if (m_mode >= CBC && (iv.isNull() || iv.size() != m_blocklen))
return QByteArray();
QByteArray ret;
QByteArray expandedKey = expandKey(key);
QByteArray alignedText(rawText);
//Fill array with padding
alignedText.append(getPadding(rawText.size(), m_blocklen));
switch(m_mode)
{
case ECB:
for(int i=0; i < alignedText.size(); i+= m_blocklen)
ret.append(cipher(expandedKey, alignedText.mid(i, m_blocklen)));
break;
case CBC: {
QByteArray ivTemp(iv);
for(int i=0; i < alignedText.size(); i+= m_blocklen) {
alignedText.replace(i, m_blocklen, byteXor(alignedText.mid(i, m_blocklen),ivTemp));
ret.append(cipher(expandedKey, alignedText.mid(i, m_blocklen)));
ivTemp = ret.mid(i, m_blocklen);
}
}
break;
case CFB: {
ret.append(byteXor(alignedText.left(m_blocklen), cipher(expandedKey, iv)));
for(int i=0; i < alignedText.size(); i+= m_blocklen) {
if (i+m_blocklen < alignedText.size())
ret.append(byteXor(alignedText.mid(i+m_blocklen, m_blocklen),
cipher(expandedKey, ret.mid(i, m_blocklen))));
}
}
break;
case OFB: {
QByteArray ofbTemp;
ofbTemp.append(cipher(expandedKey, iv));
for (int i=m_blocklen; i < alignedText.size(); i += m_blocklen){
ofbTemp.append(cipher(expandedKey, ofbTemp.right(m_blocklen)));
}
ret.append(byteXor(alignedText, ofbTemp));
}
break;
default: break;
}
return ret;
}
QByteArray QAESEncryption::decode(const QByteArray &rawText, const QByteArray &key, const QByteArray &iv)
{
if (m_mode >= CBC && (iv.isNull() || iv.size() != m_blocklen))
return QByteArray();
QByteArray ret;
QByteArray expandedKey = expandKey(key);
switch(m_mode)
{
case ECB:
for(int i=0; i < rawText.size(); i+= m_blocklen)
ret.append(invCipher(expandedKey, rawText.mid(i, m_blocklen)));
break;
case CBC: {
QByteArray ivTemp(iv);
for(int i=0; i < rawText.size(); i+= m_blocklen){
ret.append(invCipher(expandedKey, rawText.mid(i, m_blocklen)));
ret.replace(i, m_blocklen, byteXor(ret.mid(i, m_blocklen),ivTemp));
ivTemp = rawText.mid(i, m_blocklen);
}
}
break;
case CFB: {
ret.append(byteXor(rawText.mid(0, m_blocklen), cipher(expandedKey, iv)));
for(int i=0; i < rawText.size(); i+= m_blocklen){
if (i+m_blocklen < rawText.size()) {
ret.append(byteXor(rawText.mid(i+m_blocklen, m_blocklen),
cipher(expandedKey, rawText.mid(i, m_blocklen))));
}
}
}
break;
case OFB: {
QByteArray ofbTemp;
ofbTemp.append(cipher(expandedKey, iv));
for (int i=m_blocklen; i < rawText.size(); i += m_blocklen){
ofbTemp.append(cipher(expandedKey, ofbTemp.right(m_blocklen)));
}
ret.append(byteXor(rawText, ofbTemp));
}
break;
default:
//do nothing
break;
}
return ret;
}
QByteArray QAESEncryption::removePadding(const QByteArray &rawText)
{
return RemovePadding(rawText, (Padding) m_padding);
}
