The Complete SSL and TLS Guide: HTTP to HTTPS

Analyze research on SSL, TLS and HTTPS that shows rising adoption, with more than half of sites using HTTPS by 2018 and that secure setup does not guarantee full security.

Explore how Google and Instagram use https, inspect the lock icon, and learn about certificate validity, expiration, and fingerprints in the certificate chain from issuing authorities.

Explore encryption mechanisms, hash functions, and common algorithms, and introduce symmetric encryption where the same key encrypts and decrypts data. Emphasize key secrecy and non-transfer in symmetric encryption.

Explore how asymmetric keys use a public key to encrypt data and a private key to decrypt, ensuring only the owner can read the message.

Learn how asymmetric keys sign data to ensure origin and integrity by hashing data, signing with private key, and verifying with public key in SSL certificates and RSA protocol.

Explain what a certificate contains: owner, issuer, signature, and public key, and how it creates a chain of trust with certificate authorities, enabling RSA-based https encryption via PKI.

Generate RSA keys with OpenSSL and encrypt the private key with a passphrase using AES-256. Store the private key in private.pem and extract the public key to public.pem.

Explore the instagram.com certificate in practice, tracing the chain from root to intermediate to instagram.com's certificate, and examining the common name, key size, sha-256 signature, and DNS names.

Analyze comodo.com's certificate to understand the certificate chain with root and intermediate authorities, single-domain cert for comodo.com, extended validation details, and sha-256 with rsa signatures.

Explore how the chain of trust forms from root CA to intermediate CAs to end user certificates using private keys, signatures, and CSR-based signing.

Learn about certificate domain scopes—single-domain, wildcard, and multi-domain—covering common name, wildcard patterns, and subject alternative names, plus how scope affects pricing, and get a preview of TLS/SSL secure connections.

Trace the history and versions of SSL and TLS, note that SSL is deprecated, and advise using TLS certificates, with TLS 1.2 and 1.3 enabled on web servers.

Explore how tls session establishment secures https by negotiating a cipher suite, exchanging and validating certificate chains, and generating a symmetric key via public key encryption or Diffie-Hellman.

Analyze TLS session setup in practice with Wireshark, from client hello and server hello to certificate exchange, Diffie-Hellman key exchange, and establishing the symmetric key for HTTPS data using http2.

Explain how a browser obtains an encryption key without diffie-hellman by encrypting a random key with the server's public RSA key, using the certificate for authentication.

Explore how TLS uses Diffie-Hellman to deliver keys and create symmetric keys on both sides during a public exchange, with certificate verification and protection against man in the middle attacks.

Diffie-Hellman enables two parties to generate a shared key over an insecure connection without sending the key, using one-way functions, with standard mod operation and elliptic-curve variants for TLS.

Explain the modulus operation and its remainder concept with examples, show its one-way property, and connect how Diffie-Hellman uses modulus for secure key exchange.

Explore elliptic curve cryptography and how it powers TLS and Diffie-Hellman key exchange, using the curve equation y^2 = x^3 + a x + b and its symmetry about x-axis.

Explore elliptic curves, point addition and point multiplication on the curve, using line intersections to derive R from P and Q and doubling a point.

Explore elliptic-curve point addition by drawing lines through Q and R to obtain 2Q, 3Q, and 4Q, with reflections across the x-axis yielding S and L.

Learn how elliptic curve cryptography and diffie-hellman key exchange generate the same key on both sides, using g^a mod p and point addition on curves.

Set up a free hosting page on GitHub pages by creating a public repository named username.github.io, adding an index.html, and publishing to verify a valid TLS certificate.

Explore how a TLS session secures a GitHub.io site by examining a multi-domain certificate, its SANs, issuer chain, and the TLS handshake, including client hello and server hello.

Purchase a paid domain to go live with a production website. Then explore free hosting and free domain options for your first site.

Set up free hosting, connect your domain to infinityfree, configure name servers, and test DNS resolution as you prepare to install a TLS certificate to secure your site.

Acquire a virtual private server with full shell access to host a WordPress site, then obtain a free TLS certificate via certbot from Letsencrypt, valid for 90 days.

Explore popular paid hosting providers—Amazon Web Services, Google Cloud, Microsoft Azure, and Digital Ocean—with a focus on Amazon EC2 pricing, free tiers, spot and reserved instances, and scalable configurations.

Secure a WordPress site with a Let's Encrypt TLS certificate validated for the domain, and review its three-month renewal, OCSP status, and certificate chain.

Explore Let's Encrypt and certbot, a free TLS certificate service that automates domain validation and renewals via ACME, enabling secure traffic for websites.

Examine the certificate chain after issuance by inspecting live files on the server and decoding TLS certificates with online tools to verify chain integrity and protocol support.

Discover how Cloudflare acts as a reverse proxy to hide IP addresses and cache pages, saving bandwidth and reducing latency. Cloudflare offers free TLS certificates on a free plan.

Set up a Cloudflare account, add your site, and import DNS records, then switch nameservers to route traffic through Cloudflare’s reverse proxy with the free plan, CDN, and SSL certificate.

Cloudflare provides a free, automatically issued, multi-domain TLS certificate for your site, valid for any subdomains of course.com, thanks to subject alternative names such as star.course.com and course.com.

Explore how Cloudflare manages edge and origin TLS certificates, explains universal SSL, age certificates, auto renewal, and the difference between flexible, full, and full strict modes.

Explore Cloudflare SSL operation modes, from flexible to full and full strict, and how using origin certificates or Cloudflare's origin certificates enables secure HTTPS connections.

Learn how to enable Cloudflare's flexible SSL mode, using an edge certificate while the origin has no TLS, and update DNS records to test secure access.

Create a new virtual private server, install Nginx, and configure a TLS certificate on Nginx, while using Cloudflare as an intermediate reverse proxy service.

Explain how Cloudflare handles ssl modes and origin certificates to enable https. Show Cloudflare's dns, analytics, caching, and page rules.