Substitution cipher breaker [ Website ] 
This online calculator tries to decode substitution cipher without knowing the key. It uses genetic algorithm over text fitness function to break the encoded text

Intruder  [ Website ] 
s a cloud-based vulnerability scanner that finds cyber security weaknesses in your digital infrastructure, to avoid costly data breaches

Wireshark [ Website ]
Wireshark is the world’s foremost and widely-used network protocol analyzer

GnuPG Website ] 
GnuPG is a free tool for encryption of data with a lot of features like key management and access to public key directories. It has good customer reviews for data encryption.

Snort Website ] 
Snort is an open-source platform. It is an application for network intrusion prevention. It supports FreeBSD, Fedora, Centos, and Windows platform. It can perform the task of watching network packets and streaming data to your screen.