Encryption is the process of converting readable data into an unreadable format using a mathematical algorithm and a key. Without the correct key, the scrambled output is computationally impossible to reverse with current technology. Encryption is what makes private internet communication possible — it protects your passwords, financial transactions, messages, and browsing activity from being read by anyone who intercepts the data in transit.
How Encryption Works
Encryption transforms plaintext (readable data) into ciphertext (scrambled, unreadable data) using a cipher — a mathematical algorithm — controlled by an encryption key. The key determines how the data is scrambled and how it is unscrambled. Anyone without the correct key sees only random, meaningless characters when they try to read the ciphertext.
Modern encryption uses extremely long keys measured in bits. AES-256 — the standard used by VPNs and government agencies — uses a 256-bit key. This key has 2^256 possible combinations, which is more than the number of atoms in the observable universe. Even if every computer on Earth were dedicated to brute-forcing an AES-256 key, the time required would exceed the current age of the universe by many orders of magnitude. AES-256 is considered computationally unbreakable with current and near-future technology.
Symmetric Encryption: Same Key for Both Sides
Symmetric encryption uses a single key for both encrypting and decrypting data. Both the sender and receiver must have access to the same key. It is fast and efficient — ideal for encrypting large volumes of data in real time. AES (Advanced Encryption Standard) is the dominant symmetric cipher, used by VPNs, secure messaging apps, disk encryption tools, and government systems worldwide. When your VPN encrypts traffic between your device and the VPN server, it uses symmetric AES-256 to do so.
Asymmetric Encryption: Public and Private Keys
Asymmetric encryption uses two mathematically linked keys: a public key that anyone can use to encrypt data, and a private key that only the recipient holds to decrypt it. Data encrypted with the public key can only be decrypted with the corresponding private key. This system solves the key exchange problem — you can share your public key openly without risk, because only your private key can decrypt anything encrypted with it.
Asymmetric encryption powers HTTPS, digital signatures, and the initial key exchange in VPN connections. When you connect to an HTTPS website, asymmetric encryption establishes a secure channel to exchange a symmetric session key, which then handles the bulk of encrypted communication. This combination uses each type for what it does best: asymmetric for secure key exchange, symmetric for fast bulk data encryption.
Encryption in Everyday Internet Use
- HTTPS — The padlock in your browser indicates TLS encryption between your browser and the website server. Your ISP cannot read the page content, but they can see which domain you visited through DNS queries.
- VPN — Adds AES-256 encryption to all your traffic before it leaves your device. Your ISP sees only encrypted data going to a VPN server — not your destinations, not your content.
- End-to-end encryption — Used by WhatsApp, Signal, and iMessage. Only sender and recipient hold the decryption keys. Even the service provider cannot read messages.
- Password managers — Encrypt stored passwords in AES-256 vaults. If the company servers are breached, attackers obtain only encrypted ciphertext with no value.
- Full-disk encryption — Windows BitLocker and macOS FileVault encrypt every file on your device. A stolen device reveals nothing without the encryption key.
Why Proxies Are Less Secure: The Encryption Gap
This is the most important practical difference between a proxy and a VPN. A standard HTTP proxy sends your traffic in plain text — readable by anyone who intercepts it, including the proxy operator, your ISP, and anyone monitoring the network between you and the proxy. There is no encryption layer protecting the content in transit. An HTTPS proxy encrypts the connection to the proxy server, but the proxy itself decrypts the traffic before forwarding it. The proxy operator still sees everything.
A VPN encrypts everything before it leaves your device using AES-256. Even if someone intercepts the encrypted data stream, they see only meaningless ciphertext. This is why using a proxy on public Wi-Fi provides almost no real security — the lack of encryption leaves all your data readable to anyone monitoring the same network. NordVPN uses AES-256-GCM with a 4096-bit RSA key for the connection handshake — a combination that has never been broken in real-world deployment.
Frequently Asked Questions
What is encryption in simple terms?
Encryption converts readable data into scrambled, unreadable ciphertext using a mathematical key. Only someone with the correct key can reverse the process. It protects your data from being read by anyone who intercepts it — your ISP, hackers, or unauthorized parties.
Does HTTPS mean my connection is fully encrypted?
HTTPS encrypts content between your browser and the website. Your ISP cannot read page content but can still see which domain you visited through DNS queries. A VPN adds a second encryption layer that hides even domain names from your ISP by routing DNS through private servers.
What encryption does NordVPN use?
NordVPN uses AES-256-GCM for data encryption and a 4096-bit RSA key for the TLS handshake that establishes the VPN connection. This combination is considered computationally unbreakable with any current or near-future technology.
Is end-to-end encryption the same as a VPN?
No. End-to-end encryption in apps like WhatsApp ensures only sender and recipient can read messages. A VPN encrypts all network traffic at the device level regardless of application. They solve different problems and can be used simultaneously for layered protection.
