Learn OpenSSL with a real world cheatsheet

Learn how SSL and TLS protect data on the wire by providing confidentiality through encryption, integrity through hashing, and authentication via the public key infrastructure.

Discover how anti replay and non repudiation protect data in ssl and tls by combining sequence numbers with integrity and authentication to prevent replay attacks and repudiation.

Learn the SSL/TLS roles—client, server, and certificate authority—and how the client initiates a TLS handshake, the server authenticates, and certificate authorities issue server certificates.

Explore how hashing converts any input to a fixed-length message digest and evaluate its four real-world requirements, the avalanche effect, and collision concepts using MD5 and SHA examples.

Explore how hashing and message authentication codes provide data integrity and authentication in ssl/tls by combining a message with a secret key to produce and verify digests.

Understand key-based encryption to ensure confidentiality by converting plaintext to ciphertext using symmetric and asymmetric methods, with public and private keys, and compare their strengths, weaknesses, and key sizes.

Explore how public and private keys form a key pair to ensure confidentiality, authentication, and integrity, and how hybrid encryption blends asymmetric and symmetric methods for secure bulk data.

Learn how SSL and TLS use encryption, hashing, and MACs with PKI and certificate authorities to achieve confidentiality, integrity, and authentication through asymmetric key exchange for a client and server.

Explore how a public key infrastructure links clients, servers, and certificate authorities to achieve confidentiality, integrity, and authentication, with web, code signing, and internal corporate PKI examples.

Learn how DSA enables only signature generation and verification, unlike RSA or Diffie-Hellman. Recognize the need for a unique random number, or RFC 6979, in signing.

Generate and inspect RSA keys with the OpenSSL cheat sheet, creating PEM-formatted public and private key pairs in 1024- or 2048-bit sizes, with optional encrypted outputs.

Explore generating DSA parameters and keys with OpenSSL: create a DSA parameters file, generate DSA keys (displaying P, Q, G values) in text form, or do it in one step.

Learn to generate elliptic curve keys with OpenSSL by creating an EC parameters file, generating keys from it, or doing both in step, and inspect PEM files and list curves.

Learn to add and remove encryption on RSA private keys with openssl rsa, switching between unencrypted and encrypted pem files using a passphrase and verifying integrity with sha1 hashes.

Explore the OpenSSL PKI utility as an algorithm agnostic key inspector, using a single command to extract text or PEM data from RSA, DSA, and elliptic curve keys.

Generate a CSR or certificate using an existing private key (elliptic curve or RSA) and specify subject attributes such as country, state, locality, organization, and common name.

Learn to generate CSRs and certificates with private keys in a single openssl command, using no des options and the dash new key for rsa, dsa, and elliptic curve.

Extract specific pieces of information from certificates and CSRs using OpenSSL, including viewing PEM contents and retrieving subject, issuer, dates, extensions, and the public key.

Use OpenSSL to identify PEM, DER, and PFX file formats by testing cert and key files with x509 and related openssl utilities, then rename each file with the correct extension.

Learn to convert between pem and pfx formats with OpenSSL pkcs12, exporting certificates and private keys while managing export passwords and key and certificate pairs.

Discover deeper TLS and SSL concepts through Ed's Practical TLS course, a 10-hour video deep dive with 30 plus labs and free YouTube modules, covering cryptography, handshake, and revocation certificates.