5 #ifndef BITCOIN_CRYPTO_CHACHA20_H     6 #define BITCOIN_CRYPTO_CHACHA20_H    19     ChaCha20(
const unsigned char* key, 
size_t keylen);
    20     void SetKey(
const unsigned char* key, 
size_t keylen);
    21     void SetIV(uint64_t iv);
    22     void Seek(uint64_t pos);
    23     void Output(
unsigned char* output, 
size_t bytes);
    26 #endif // BITCOIN_CRYPTO_CHACHA20_H 
void Output(unsigned char *output, size_t bytes)
 
A PRNG class for ChaCha20. 
 
void SetKey(const unsigned char *key, size_t keylen)