squeezelite-esp32/components/spotify/cspot/include/Shannon.h

#ifndef SHANNON_H
#define SHANNON_H

#include <cstdint>
#include <vector>
class Shannon
{
public:
    static constexpr unsigned int N = 16;

    void key(const std::vector<uint8_t> &key);     /* set key */
    void nonce(const std::vector<uint8_t> &nonce); /* set Init Vector */
    void stream(std::vector<uint8_t> &buf);  /* stream cipher */
    void maconly(std::vector<uint8_t> &buf); /* accumulate MAC */
    void encrypt(std::vector<uint8_t> &buf); /* encrypt + MAC */
    void decrypt(std::vector<uint8_t> &buf); /* decrypt + MAC */
    void finish(std::vector<uint8_t> &buf);  /* finalise MAC */

private:
    static constexpr unsigned int FOLD = Shannon::N;
    static constexpr unsigned int INITKONST = 0x6996c53a;
    static constexpr unsigned int KEYP = 13;
    uint32_t R[Shannon::N];
    uint32_t CRC[Shannon::N];
    uint32_t initR[Shannon::N];
    uint32_t konst;
    uint32_t sbuf;
    uint32_t mbuf;
    int nbuf;
    static uint32_t sbox1(uint32_t w);
    static uint32_t sbox2(uint32_t w);
    void cycle();
    void crcfunc(uint32_t i);
    void macfunc(uint32_t i);
    void initState();
    void saveState();
    void reloadState();
    void genkonst();
    void diffuse();
    void loadKey(const std::vector<uint8_t> &key);
};

#endif