squeezelite-esp32/components/spotify/cspot/bell/main/utilities/include/Crypto.h

#ifndef BELL_CRYPTO_H
#define BELL_CRYPTO_H

#include <string>  // for string
#include <vector>  // for vector

#include <mbedtls/aes.h>  // for mbedtls_aes_context
#include <mbedtls/md.h>   // for mbedtls_md_context_t
#include <stddef.h>       // for size_t
#include <stdint.h>       // for uint8_t

#define DH_KEY_SIZE 96

const static unsigned char DHPrime[] = {
    /* Well-known Group 1, 768-bit prime */
    0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc9, 0x0f, 0xda, 0xa2,
    0x21, 0x68, 0xc2, 0x34, 0xc4, 0xc6, 0x62, 0x8b, 0x80, 0xdc, 0x1c, 0xd1,
    0x29, 0x02, 0x4e, 0x08, 0x8a, 0x67, 0xcc, 0x74, 0x02, 0x0b, 0xbe, 0xa6,
    0x3b, 0x13, 0x9b, 0x22, 0x51, 0x4a, 0x08, 0x79, 0x8e, 0x34, 0x04, 0xdd,
    0xef, 0x95, 0x19, 0xb3, 0xcd, 0x3a, 0x43, 0x1b, 0x30, 0x2b, 0x0a, 0x6d,
    0xf2, 0x5f, 0x14, 0x37, 0x4f, 0xe1, 0x35, 0x6d, 0x6d, 0x51, 0xc2, 0x45,
    0xe4, 0x85, 0xb5, 0x76, 0x62, 0x5e, 0x7e, 0xc6, 0xf4, 0x4c, 0x42, 0xe9,
    0xa6, 0x3a, 0x36, 0x20, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};

static unsigned char DHGenerator[1] = {2};

class CryptoMbedTLS {
 private:
  mbedtls_md_context_t sha1Context;
  mbedtls_aes_context aesCtx;
  bool aesCtxInitialized = false;

 public:
  CryptoMbedTLS();
  ~CryptoMbedTLS();
  // Base64
  std::vector<uint8_t> base64Decode(const std::string& data);
  std::string base64Encode(const std::vector<uint8_t>& data);

  // Sha1
  void sha1Init();
  void sha1Update(const std::string& s);
  void sha1Update(const std::vector<uint8_t>& vec);
  std::string sha1Final();
  std::vector<uint8_t> sha1FinalBytes();

  // HMAC SHA1
  std::vector<uint8_t> sha1HMAC(const std::vector<uint8_t>& inputKey,
                                const std::vector<uint8_t>& message);

  // AES CTR
  void aesCTRXcrypt(const std::vector<uint8_t>& key, std::vector<uint8_t>& iv,
                    uint8_t* data, size_t nbytes);

  // AES ECB
  void aesECBdecrypt(const std::vector<uint8_t>& key,
                     std::vector<uint8_t>& data);

  // Diffie Hellman
  std::vector<uint8_t> publicKey;
  std::vector<uint8_t> privateKey;
  void dhInit();
  std::vector<uint8_t> dhCalculateShared(const std::vector<uint8_t>& remoteKey);

  // PBKDF2
  std::vector<uint8_t> pbkdf2HmacSha1(const std::vector<uint8_t>& password,
                                      const std::vector<uint8_t>& salt,
                                      int iterations, int digestSize);

  // Random stuff
  std::vector<uint8_t> generateVectorWithRandomData(size_t length);
};

#define Crypto CryptoMbedTLS

#endif