qaesencryption.h

#ifndef QAESENCRYPTION_H
#define QAESENCRYPTION_H

#ifdef QtAES_EXPORTS
#include "qtaes_export.h"
#else
#define QTAESSHARED_EXPORT
#endif

#include <QObject>
#include <QByteArray>
#include <QCryptographicHash>
#include <QMessageAuthenticationCode>

#ifdef QTAES_CONSTANT_TIME_SBOX
#include "aes_ct_sbox.h"
#endif

#ifdef __linux__
#ifndef __LP64__
#define do_rdtsc _do_rdtsc
#endif
#endif

/*!
 * \class QAESEncryption
 * \brief AES encryption/decryption for Qt supporting 128/192/256-bit keys and ECB, CBC, CFB, OFB, CTR modes.
 *
 * \note \b Thread safety: instances are thread-safe for concurrent encode/decode calls.
 *       All mutable state during an operation is kept on the call stack; no member variables
 *       are written after construction. The static methods (Crypt, Decrypt, ExpandKey,
 *       RemovePadding, generateKey) are also safe to call concurrently.
 *
 * \note \b API stability: encode(), decode(), removePadding(), and the static equivalents
 *       (Crypt, Decrypt, RemovePadding, generateKey) form the stable public surface.
 *       ExpandKey() is provided for advanced use and may change in future versions.
 */
class QTAESSHARED_EXPORT QAESEncryption : public QObject
{
    Q_OBJECT
public:
    enum Aes {
        AES_128,
        AES_192,
        AES_256
    };

    enum Mode {
        ECB,
        CBC,
        CFB,
        OFB,
        CTR  ///< Counter mode — stream cipher, no padding, encrypt == decrypt
    };

    enum Padding {
      ZERO,
      PKCS7,
      ISO,
      NONE  ///< No padding — valid only for CFB and OFB (stream cipher modes); allows arbitrary-length plaintext.
    };

    /*!
     * \brief static method call to encrypt data given by rawText
     * \param level:    AES::Aes level
     * \param mode:     AES::Mode mode
     * \param rawText:  input text
     * \param key:      user-key (key.size either 128, 192, 256 bits depending on AES::Aes)
     * \param iv:       initialisation-vector (iv.size is 128 bits (16 Bytes))
     * \param padding:  AES::Padding standard
     * \param ok:       if non-null, set to true on success or false if key/IV/alignment is invalid
     * \return encrypted cipher
     */
    static QByteArray Crypt(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &rawText, const QByteArray &key,
                            const QByteArray &iv = QByteArray(), QAESEncryption::Padding padding = QAESEncryption::ISO,
                            bool *ok = nullptr);
    /*!
     * \brief static method call to decrypt data given by rawText
     * \param level:    AES::Aes level
     * \param mode:     AES::Mode mode
     * \param rawText:  input text
     * \param key:      user-key (key.size either 128, 192, 256 bits depending on AES::Aes)
     * \param iv:       initialisation-vector (iv.size is 128 bits (16 Bytes))
     * \param padding:  AES::Padding standard
     * \param ok:       if non-null, set to true on success or false if key/IV/alignment is invalid
     * \return decrypted cipher with padding
     */
    static QByteArray Decrypt(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &rawText, const QByteArray &key,
                              const QByteArray &iv = QByteArray(), QAESEncryption::Padding padding = QAESEncryption::ISO,
                              bool *ok = nullptr);
    /*!
     * \brief Expand a raw key into the Rijndael key schedule (advanced use).
     *
     * Most callers do not need this — encode() and decode() handle key expansion
     * internally. This method is provided for advanced scenarios where the caller
     * wants to inspect or cache the expanded key schedule.
     *
     * \param level            AES key size.
     * \param mode             Cipher mode (affects key schedule direction).
     * \param key              Raw user key (16, 24, or 32 bytes).
     * \param isEncryptionKey  Pass \c true for encryption; \c false only when
     *                         decrypting with AES-NI in ECB or CBC mode.
     * \return Expanded key schedule bytes.
     */
    static QByteArray ExpandKey(QAESEncryption::Aes level, QAESEncryption::Mode mode, const QByteArray &key, bool isEncryptionKey);

    /*!
     * \brief static method call to remove padding from decrypted cipher given by rawText
     * \param rawText:  inputText
     * \param padding:  AES::Padding standard
     * \return decrypted cipher with padding removed
     */
    static QByteArray RemovePadding(const QByteArray &rawText, QAESEncryption::Padding padding = QAESEncryption::ISO,
                                    bool *ok = nullptr);

    /*!
     * \brief Derives an AES-ready key from a password and salt using PBKDF2 (RFC 2898).
     *        Only QtCore is required — no QtNetwork dependency.
     * \param password   User-supplied password.
     * \param salt       Random salt (store alongside ciphertext; do not reuse across encryptions).
     * \param level      Target AES key size: AES_128 => 16 bytes, AES_192 => 24 bytes, AES_256 => 32 bytes.
     * \param algo       HMAC hash algorithm (default: Sha256).
     * \param iterations PBKDF2 iteration count (default: 10000; capped at 500000).
     * \return Derived key of the exact byte length required by \a level, or empty on invalid input.
     *
     * \note This implementation uses Qt's QMessageAuthenticationCode, which is a general-purpose
     *       utility and is not guaranteed to be constant-time or security-audited as a cryptographic
     *       primitive. For security-critical applications, prefer a dedicated library such as
     *       OpenSSL (PKCS5_PBKDF2_HMAC) or libsodium.
     */
    static QByteArray generateKey(const QByteArray &password,
                                  const QByteArray &salt,
                                  QAESEncryption::Aes level,
                                  QCryptographicHash::Algorithm algo = QCryptographicHash::Sha256,
                                  int iterations = 10000);

    QAESEncryption(QAESEncryption::Aes level, QAESEncryption::Mode mode,
                   QAESEncryption::Padding padding = QAESEncryption::ISO);



    /*!
     * \brief object method call to encrypt data given by rawText
     * \param rawText:  input text
     * \param key:      user-key (key.size either 128, 192, 256 bits depending on AES::Aes)
     * \param iv:       initialisation-vector (iv.size is 128 bits (16 Bytes))
     * \return encrypted cipher
     */
    QByteArray encode(const QByteArray &rawText, const QByteArray &key, const QByteArray &iv = QByteArray(),
                      bool *ok = nullptr);

    /*!
     * \brief object method call to decrypt data given by rawText
     * \param rawText:  input text
     * \param key:      user-key (key.size either 128, 192, 256 bits depending on AES::Aes)
     * \param iv:       initialisation-vector (iv.size is 128 bits (16 Bytes))
     * \param padding:  AES::Padding standard
     * \return decrypted cipher with padding
     */
    QByteArray decode(const QByteArray &rawText, const QByteArray &key, const QByteArray &iv = QByteArray(),
                      bool *ok = nullptr);

    /*!
     * \brief object method call to remove padding from decrypted cipher given by rawText
     * \param rawText:  inputText
     * \param ok:       if non-null, set to true on success or false if PKCS7 padding is invalid
     * \return decrypted cipher with padding removed
     */
    QByteArray removePadding(const QByteArray &rawText, bool *ok = nullptr);

Q_SIGNALS:

public Q_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;
    bool m_aesNIAvailable;

    QByteArray expandKey(const QByteArray &key, bool isEncryptionKey);

#ifdef QTAES_CONSTANT_TIME_SBOX
    quint8 getSBoxValue(quint8 num){return AesCt::sbox(num);}
    quint8 getSBoxInvert(quint8 num){return AesCt::invSbox(num);}
#else
    quint8 getSBoxValue(quint8 num){return sbox[num];}
    quint8 getSBoxInvert(quint8 num){return rsbox[num];}
#endif

    void addRoundKey(QByteArray &state, const quint8 round, const QByteArray &expKey);
    void subBytes(QByteArray &state);
    void shiftRows(QByteArray &state);
    void mixColumns(QByteArray &state);
    void invMixColumns(QByteArray &state);
    void invSubBytes(QByteArray &state);
    void invShiftRows(QByteArray &state);
    QByteArray getPadding(int currSize, int alignment);
    QByteArray cipher(const QByteArray &expKey, const QByteArray &in);
    QByteArray invCipher(const QByteArray &expKey, const QByteArray &in);
    QByteArray byteXor(const QByteArray &a, const QByteArray &b);
    QByteArray xcryptOFB(const QByteArray &input, const QByteArray &expandedKey, const QByteArray &iv);
    QByteArray xcryptCTR(const QByteArray &input, const QByteArray &expandedKey, const QByteArray &iv);

    const quint8 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,
      0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
      0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
      0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
      0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
      0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
      0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
      0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
      0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
      0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
      0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
      0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
      0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
      0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
      0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
      0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };

    const quint8 rsbox[256] = {
      0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
      0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
      0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
      0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
      0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
      0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
      0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
      0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
      0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
      0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
      0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
      0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
      0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
      0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
      0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
      0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };

    // 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(2^8)
    // Only the first 14 elements are needed
    const quint8 Rcon[14] = {
        0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab};
};

#endif // QAESENCRYPTION_H