/Users/baford/proj/netsteria/sst/lib/aes.h

#ifndef SST_AES_H
#define SST_AES_H

#include <openssl/aes.h>

class QByteArray;

namespace SST {

class AES
{
private:
        AES_KEY aeskey;

public:
        enum Mode {
                CbcEncrypt,
                CbcDecrypt,
                CtrEncrypt = CbcEncrypt,
                CtrDecrypt = CbcEncrypt,
        };

        // Key setup
        AES &setEncryptKey(const void *key, int bits);
        AES &setEncryptKey(const QByteArray &key);

        AES &setDecryptKey(const void *key, int bits);
        AES &setDecryptKey(const QByteArray &key);

        inline AES() { }
        inline AES(const AES &other) { aeskey = other.aeskey; }
        inline AES(const QByteArray &key, Mode mode)
                { mode == CbcEncrypt ? setEncryptKey(key)
                                : setDecryptKey(key); }


        // CBC-mode encryption and decryption

        // "Raw" functions.  Cleartext buffers can be any size,
        // but encrypted data is padded to AES_BLOCK_SIZE.
        // The supplied initialization vector is updated in-place.
        void cbcEncrypt(const void *in, void *out, int size, void *ivec) const;
        void cbcDecrypt(const void *in, void *out, int size, void *ivec) const;

        // Higher-level functions - create and prepend random 16-byte IV.
        // cbcEncrypt pads input to a multiple of AES_BLOCK_SIZE;
        // cbcDecrypt does NOT strip this padding.
        QByteArray cbcEncrypt(const QByteArray &in) const;
        QByteArray cbcDecrypt(const QByteArray &in) const;


        // Encrypt/decrypt in counter mode.
        inline void ctrEncrypt(const void *in, void *out, int size,
                                void *ivec, void *ctr, unsigned int &num) const
                { AES_ctr128_encrypt((const quint8*)in, (quint8*)out, size,
                                &aeskey, (quint8*)ivec, (quint8*)ctr, &num); }
        inline void ctrDecrypt(const void *in, void *out, int size,
                                void *ivec, void *ctr, unsigned int &num) const
                { AES_ctr128_encrypt((const quint8*)in, (quint8*)out, size,
                                &aeskey, (quint8*)ivec, (quint8*)ctr, &num); }

        inline void ctrEncrypt(const void *in, void *out, int size,
                                void *ivec) const
                { quint8 ctr[AES_BLOCK_SIZE]; unsigned num = 0;
                  ctrEncrypt(in, out, size, ivec, ctr, num); }
        inline void ctrDecrypt(const void *in, void *out, int size,
                                void *ivec) const
                { quint8 ctr[AES_BLOCK_SIZE]; unsigned num = 0;
                  ctrDecrypt(in, out, size, ivec, ctr, num); }
};

} // namespace SST

#endif  // SST_AES_H

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