Encryption

Encryption converts plaintext data into ciphertext using a key, making it unreadable without the corresponding decryption key. HTTPS (TLS) encryption is standard for internet communication, protecting data between browsers and web servers.

The most important fact about QR codes and encryption: standard QR codes (ISO/IEC 18004) have no data encryption capability. Text, URLs, Wi-Fi passwords, and any other data stored in a QR code can be read in plaintext by anyone who scans it. Error correction repairs damaged data but is fundamentally different from encryption.

A representative practical example of an encrypted QR code is SQRC, developed by Denso Wave. SQRC has a two-layer structure with public and private data areas, where private data requires a dedicated reader. It targets uses such as manufacturingtraceability and anti-counterfeiting, but the dedicated reader requirement makes it unsuitable for general consumer use. For typical applications, the standard design stores only an HTTPS URL in the QR code and handles sensitive data through server-side authentication. Instead of encrypting the QR code itself, keep the payload a hard-to-guess random URL and require a login on the destination page, which protects the sensitive part without any special reader.