What is a OpenSSL ? Write a usage and syntax of OpenSSL.
1 Answer



  • 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.

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