OpenSSL Command Generator
Build correct OpenSSL commands in seconds. Pick a task, fill in the file names and options, then copy the ready-to-run command into your terminal. Nothing runs here and nothing is uploaded — the command text is created in your browser only.
chmod 600 your-key.key
How to use
- Choose a task from the list, for example generating an RSA private key or a self-signed certificate.
- Fill in the fields that appear: key size, number of days, your certificate details (CN, O, C) and the input and output file names.
- The command is generated live. Click Copy command and paste it into your terminal on a machine with OpenSSL installed.
- For the key-match check, run both shown commands: if the two hashes are identical, the key and certificate belong together.
Note: Commands are only generated as text in your browser; nothing is executed or uploaded. A larger key size (3072 or 4096 bits) is more secure but slightly slower. PEM is the default text format OpenSSL uses; DER is the binary form; PFX/PKCS12 bundles a certificate and key into one password-protected file.
Frequently Asked Questions (FAQ)
What does the OpenSSL Command Generator do?
It builds ready-to-run OpenSSL commands for private keys, self-signed certificates, CSRs, format conversion, certificate checks and file encryption, from the options you pick.
Do I need to install anything?
No. The commands are generated in your browser. You run them on any computer that has OpenSSL installed, for example most Linux and macOS systems.
How do I check a private key matches a certificate?
Pick the check-match task, enter your key and certificate file names, and run the two modulus-hash commands. If both hashes are identical, the key and certificate belong together.
Is it safe to generate private keys this way?
The tool only writes the command text, so your keys are created on your own machine and never leave it. Always keep private key files secret and back them up safely.