Suggest an editImprove this articleRefine the answer for “What is TLS?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**TLS (Transport Layer Security)** is a **security protocol** that encrypts data while it travels over a network and protects the connection between a client and a server. In simple terms, it is the technology that makes data transfer over the internet secure. **Key point:** TLS provides confidentiality, integrity, and confirmation of the server's authenticity, and HTTPS is HTTP running on top of TLS.Shown above the full answer for quick recall.Answer (EN)Image**TLS (Transport Layer Security)** is a **security protocol** that **encrypts data while it travels over a network** and protects the connection between a client and a server. In simple terms: **TLS is the technology that makes data transfer over the internet secure**. --- ## Why TLS is needed TLS solves **three important tasks** at once. ### 1. Confidentiality (encryption) - data is transferred **in encrypted form** - outsiders cannot read it (passwords, tokens, personal data) --- ### 2. Data integrity - data **cannot be changed unnoticed** - if someone tries to tamper with the information, it will be detected --- ### 3. Authenticity confirmation - the client understands that it is talking **to the real server** - not to a fake site --- ## Where TLS is used TLS is used in: - **HTTPS** (the most common example) - secure mail (SMTPS, IMAPS) - VPN - messengers - APIs and microservices Practically **the entire modern internet runs on top of TLS**. --- ## How TLS works (simplified) 1. The client connects to the server 2. The server sends a **TLS certificate** 3. The client checks the certificate: - whether it is valid - who it was issued to 4. The parties agree on encryption keys 5. From then on, all data is transferred **in encrypted form** The user does not see this, it all happens automatically. --- ## TLS and HTTPS, a common mix-up Important to remember: - **TLS** is the encryption protocol - **HTTPS** is **HTTP running on top of TLS** The formula: > **HTTPS = HTTP + TLS** --- ## TLS vs SSL Interviews may ask about this: - **SSL** is the old protocol, **now outdated** - **TLS** is the modern standard Nowadays, when people say "SSL", they almost always **mean TLS**. --- ## Real-life example TLS is like: - a sealed, tamper-proof envelope - even if the letter is intercepted, it cannot be read - and its contents cannot be swapped unnoticed --- ## Short answer for an interview Remember this wording: > **TLS is a security protocol that ensures the encryption, integrity, and authenticity of data during network transfer and is used, among other things, to protect HTTPS connections.**For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.