Solution

OpenSSL

• OpenSSL is an open-source implementation of the SSL and TLS protocols.

• The OpenSSL library is the most commonly used open source library for establishing encrypted connections.

• The OpenSSL command is present by default on most Unix-based systems. Under Windows, you can use the command as provided by the Cygwin environment or you can build OpenSSL from source.

• The core library, written in the C programming language, implements basic cryptographic.

• SSL establishes confidentiality by preventing view of plaintext traffic and provides integrity by establishing a trusted identity of the web server to prevent intermediation attacks that try to manipulate traffic without being detected.

• The SSL and TLS protocols also establish the identity of a web site.

• This (mostly) prevents an attacker from spoofing web sites or performing intermediation attacks in which a hacker intercepts, modifies, and forwards a victim’s traffic without their knowledge.

• It is used for :

  • Creating key for RSA, DSA

  • Creating X.509 certificate

  • Message digest calculation

  • Handling of S/MIME signed

  • SSL / TLS client and server tests

  • Encryption and decryption with ciphers

• Syntax:

  • $ openssl command [command options] [command arguments] - Example: $ openssl list-cipher-commands

  • It will give output in the form of algorithm name, key size and blockoption of algorithm.