OpenSSL

Swiss Army knife for practical crypto plumbing. Also a terrific way to learn that syntax is a form of weather.

When to use OpenSSL

Use OpenSSL when you need to:

• encrypt or decrypt data with a known algorithm and secret
• hash or HMAC files quickly from the terminal
• inspect X.509 certificates or PEM/DER material
• check private-key structure or convert key formats

Quick Start

# SHA-256 digest
openssl dgst -sha256 file.bin