There are several ways to securely store and retrieve sensitive data in PHP:
- Use HTTPS: Always use HTTPS for transmitting sensitive data over the internet. HTTPS encrypts the data in transit, which prevents it from being intercepted by attackers.
- Don’t store sensitive data in cookies: Cookies are not a secure place to store sensitive data. Instead, use server-side sessions to store sensitive data.
- Use secure password hashing algorithms: Use secure password hashing algorithms such as bcrypt or Argon2 to store passwords. Never use MD5 or SHA1.
- Parameterize SQL queries: Always use parameterized SQL queries to prevent SQL injection attacks.
- Use prepared statements: Prepared statements are similar to parameterized queries and can help prevent SQL injection attacks.
- Obfuscate configuration files: If you need to store sensitive data in a configuration file, store it in an obfuscated form. For example, use base64 encoding to store the data.
- Use server-side encryption: Use server-side encryption to encrypt sensitive data at rest. This will prevent attackers from accessing the data if they gain access to the server.
- Use a secure file system: Use a secure file system to store sensitive data. Make sure that the file system is properly secured and that access is restricted to authorized users only.
- Use least privilege: Limit the access of users to sensitive data to the extent it is needed. This reduces the probability of data breach.
- Perform frequent security audits: Regularly conduct security audits to check if the data is being stored and retrieved securely.