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.

Compare http and https by inspecting a real site's network traffic, noting http is not secure and https uses encryption, ports 80 versus 443.

Install and run wireshark to capture traffic, filter by ip, and observe that the session uses tcp or tls to illustrate http vs https.

Explore the tcp/ip stack by example with wireshark, examining ethernet, IPv4, tcp, and tls headers, and tracing http and https traffic on port 443.

Analyze http traffic with wireshark by capturing an example.com get request, ip addresses, and a 200 response delivering html and json data in clear text.

Observe how https traffic captured with Wireshark uses TLS 1.2, with HTTP over TLS and the TLS record layer encrypting all data with symmetric key encryption and RSA keys.

Explore encryption fundamentals, compare symmetric and asymmetric methods, and learn how RSA protocol works, public key infrastructure, and hashing algorithms like MD5 and SHA are used.

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.

Hashes produce fixed-length, irreversible strings from input data to verify integrity, with md5 and sha algorithms discussed for ssl tls context, and changing a single bit yields a different hash.

Explore MD5, a fixed 128-bit one-way hash used for password storage, and learn how comparing two hashes proves data was not mutated.

Explore the Sha hashing algorithm family from Sha-1 to Sha-512, generate and compare hashes using Mac and command line tools, and learn how Mac adds a secret key for authentication.

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.

Discover the rsa public key cryptosystem and its key pair generation, enabling encryption, decryption, and signing for certificate-based communications in public key infrastructure, with 2048-bit keys and private key secrecy.

Learn the public key infrastructure (PKI) that underpins https, including certificates and public keys. See how certificate authorities and intermediate CAs establish a chain of trust for encryption and authentication.

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.

Explain how public key infrastructure underpins SSL and TLS, define certificates, certificate authority, chain of trust, and demonstrate using OpenSSL to create RSA keys, certificate signing requests, and certificates.

Learn to install OpenSSL to generate RSA keys and create a certificate signing request, with step-by-step guidance for Windows installers and notes that Mac users already have OpenSSL.

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 the google.com certificate chain, including root and intermediate authorities, a wildcard domain, multi-domain extensions, and details such as expiration, subject, issuer, 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.

Understand what a root certificate authority is, why root certificates are self-signed, and how operating systems and browsers trust them via system roots, intermediate CAs, and the chain of trust.

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.

Explore how browsers verify an HTTPS certificate by validating end user certificate against intermediate and root certificates, checking validity periods, signatures, and OS certificate store to establish a secure connection.

Learn how browsers verify complete certificate chains, including end-entity, intermediate, and root certificates, and validate subject alternative names and hostname matches for google.com and facebook.com.

Learn how public key infrastructure creates trust between certification authorities and end users through certificates, root and intermediate authorities, forming a verifiable chain of trust for web connections.

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.

Explore TLS details, from session setup and algorithms to the Keeper suite, encryption key generation, Diffie-Hellman and elliptic curve Diffie-Hellman exchanges, and elliptic curve cryptography.

Learn how ssl and tls provide encryption in https and how certificates establish browser-server trust, independent of the protocol; a certificate can be used with either ssl or tls.

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.

Explain why rsa is not used for data encryption in https and how tls sets up a secure connection and encrypts data using a symmetric key.

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.

Explore cipher suites in TLS, comparing key exchange methods like Diffie-Hellman and elliptic curve Diffie-Hellman, and the roles of ChaCha encryption protocol and SHA-256 hashing in secure sessions.

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.

Learn how the Diffie-Hellman key exchange uses modulus operations to generate a shared key over an insecure connection, leveraging private and public keys in a two-packet 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.

Explore point doubling and point addition on elliptic curves to optimize calculations, demonstrate how 67q decomposes into doubling and addition, and preview elliptic curve discrete log and Diffie-Hellman connections.

Explain the elliptic curve discrete log problem: from G and E the multiplier N cannot be determined. Relate elliptic curve cryptography key generation to Diffie-Hellman style exchanges over insecure tunnels.

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.

Learn how elliptic curve cryptography enables a Diffie-Hellman style key exchange between Alice and Bob, producing a shared TLS symmetric key and highlighting the elliptic curve discrete log problem.

Explore how to set up three domains with free hosting and a free TLS certificate using GitHub Pages.

Discover how to use free domains and hosting to launch a site on GitHub Pages and enable https with a certificate.

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.

Explore TLS session setup with elliptic curve diffie-hellman key exchange, RSA signing, 128-bit encryption, and GCM mode, plus SHA-256 integrity and OCSP certificate validation.

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

Plan next steps by purchasing a custom domain, setting up hosting and certificates, and comparing free hosting with paid domain options and free certificates.

Purchase a practice domain and learn to manage registrar settings, privacy options, and renewal reminders to secure control while exploring DNS and TLS certificate basics for a secure 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.

Install a free tls certificate on free hosting via cPanel, address self-signed warnings, and learn to generate a key pair and obtain a valid certificate; note premium limits.

Explore a hands-on attempt to install a free Let's Encrypt TLS certificate on free hosting, covering automatic FTP verification, manual DNS verification, and why the effort fails.

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.

Explore pricing and hosting options across Google Cloud, Azure, and DigitalOcean, noting free tiers, VM configurations, and preemptible pricing.

Launch a WordPress site on a Digital Ocean Ubuntu droplet, configure DNS and A records, then secure it with Letsencrypt SSL and redirect HTTP to HTTPS.

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.

Complete WordPress installation on a TLS-secured site on a DigitalOcean droplet, log in to admin, and confirm automatic redirects from http to https while preparing for certbot and certificate management.

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.

Explore certbot configuration and renewal workflow, including Letsencrypt folders, renewal setup, and the cron timer that automatically renews certificates.

Secure your domain on Digital Ocean with free TLS from Let's Encrypt via certbot and ACME, renewed every 90 days, and explore Cloudflare while analyzing TLS sessions with Wireshark.

We start using Cloudflare to learn how a reverse proxy works and how it provides free TLS encryption, even without a certificate on your servers.

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.

Review the setup: a paid domain on Digital Ocean hosting WordPress on Ubuntu 18.04 with Let’s Encrypt TLS certificate served via https, and plan to move DNS to Cloudflare.

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.

Explain Cloudflare SSL operation modes—off, flexible, full, and full strict—and how browser to cloudflare and cloudflare to origin encryption works, plus origin certificate handling.

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

Assess the setup: a single Digital Ocean droplet with WordPress, TLS, and Cloudflare in strict mode, and plan to install nginx on a new droplet with a Cloudflare origin certificate.

Create a droplet with Ubuntu 18.04, install nginx, and configure ufw firewall for HTTP, HTTPS, and SSH. Verify nginx works over HTTP and note HTTPS requires further TLS configuration.

Set up nginx on a fresh Ubuntu droplet, create a server block for course.com, and verify the nginx configuration before restarting to serve http and https.

Install a cloudflare origin TLS certificate on nginx, configure the ssl server block, and verify https connectivity across full and full strict modes.

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

Disable Cloudflare by switching the domain’s name servers to DigitalOcean and updating A records to point to a new nginx droplet, then verify the direct SSL/TLS configuration.