chmod 644 vs 600
| Property | chmod 644 | chmod 600 |
|---|---|---|
| Octal | 644 |
600 |
| Symbolic | rw-r--r-- |
rw------- |
| Owner | read/write | read/write |
| Group | read | no access |
| Others | read | no access |
| Risk Level | Low Risk | Restrictive |
| Typical Use | Web server assets including HTML, CSS, JavaScript, and PHP files | SSH private keys (e.g., ~/.ssh/id_ed25519, ~/.ssh/id_rsa) |
Key Difference
- Group: chmod 644 grants read (4), while chmod 600 grants no access (0).
- Others: chmod 644 grants read (4), while chmod 600 grants no access (0).
Which Should You Use?
Mode 644 and mode 600 separate public operational files from confidential system secrets. Under mode 644, the file owner can read and edit the file, while everyone else on the system can read its contents. This makes 644 the ideal permission for website stylesheets, JavaScript assets, documentation, and public keys like id_ed25519.pub. In sharp contrast, mode 600 strips all read and write privileges from both group members and external users, allowing only the file owner to access it. Sensitive files like database connection strings, API tokens in .env files, private keys, and session cookies must always be set to 600. Leaving a secret file configured as 644 allows any unprivileged user or compromised service on the host to read confidential keys.
Frequently Asked Questions
Is 600 more secure than 644?
Yes. Mode 600 is far more secure for private data because it prevents all other system users and background processes from reading file contents.
Can I convert 644 to 600?
Yes. To protect a secret file, run "chmod 600 secret.env" or remove group and other permissions with "chmod go-rwx secret.env".
Which is better for web servers?
Public assets served to web visitors require 644 so the web daemon can read them. Backend server configuration files holding database credentials should be owned by the web user and locked down to 600.
Related Permissions & Comparisons
Read in-depth breakdowns for chmod 644 (rw-r--r--) and chmod 600 (rw-------), or browse other permission comparisons: