chacha_encrypt_bytes
extern void chacha_encrypt_bytes(chacha_ctx_t *, const uint8_t *, uint8_t *,
chacha_encrypt_bytes(&arc4->arc4_chacha, arc4->arc4_buf, arc4->arc4_buf,
chacha_encrypt_bytes(&ctx, res0, res0, sizeof (res0));
chacha_encrypt_bytes(&ctx, res1, res1, sizeof (res1));