Introduce extra delay before closing unauthenticated sessions To make it harder for attackers, introduce a delay to keep an unauthenticated session open a bit longer, thus blocking a connection slot until after the delay. Without this, while there is a limit on the amount of attempts an attacker can make at the same time (MAX_UNAUTH_PER_IP), the time taken by dropbear to handle one attempt is still short and thus for each of the allowed parallel attempts many attempts can be chained one after the other. The attempt rate is then: "MAX_UNAUTH_PER_IP / <process time of one attempt>". With the delay, this rate becomes: "MAX_UNAUTH_PER_IP / UNAUTH_CLOSE_DELAY".

#ifndef DROPBEAR_DH_GROUPS_H
#define DROPBEAR_DH_GROUPS_H
#include "options.h"

#if DROPBEAR_NORMAL_DH

#if DROPBEAR_DH_GROUP1
#define DH_P_1_LEN 128
extern const unsigned char dh_p_1[DH_P_1_LEN];
#endif

#if DROPBEAR_DH_GROUP14
#define DH_P_14_LEN 256
extern const unsigned char dh_p_14[DH_P_14_LEN];
#endif

#if DROPBEAR_DH_GROUP16
#define DH_P_16_LEN 512
extern const unsigned char dh_p_16[DH_P_16_LEN];
#endif

extern const int DH_G_VAL;

#endif /* DROPBEAR_NORMAL_DH */

#endif