Openssl Generate Rsa 256 Key Pair
$ openssl rsa -pubout -in privatekey.pem -out publickey.pem writing RSA key A new file is created, publickey.pem, with the public key. It is relatively easy to do some cryptographic calculations to calculate the public key from the prime1 and prime2 values in the public key file. How to generate RSA and EC keys with OpenSSL. How to generate keys in PEM format using the OpenSSL command line tools? The JOSE standard recommends a minimum RSA key size of 2048 bits. To generate a 2048-bit RSA private + public key pair for use in RSxxx and PSxxx signatures.
| # Generate Private Key and Certificate using RSA 256 encryption (4096-bit key) |
| openssl req -x509 -newkey rsa:4096 -keyout privatekey.pem -out certificate.pem -days 365 |
| # Alternatively, setting the '-newkey' parameter to 'rsa:2048' will generate a 2048-bit key. |
| # Generate PKCS#12 (P12) file for cert; combines both key and certificate together |
| openssl pkcs12 -export -inkey privatekey.pem -in certificate.pem -out cert.pfx |
| # Generate SHA256 Fingerprint for Certificate and export to a file |
| openssl x509 -noout -fingerprint -sha256 -inform pem -in certificate.pem >> fingerprint.txt |
| # Generate SHA1 Fingerprint for Certificate and export to a file |
| #openssl x509 -noout -fingerprint -sha1 -inform pem -in certificate.pem >> fingerprint.txt |
| # FYI, it's best practice to use SHA256 instead of SHA1 for better security, but this shows how to do it if you REALLY need to. |
commented Nov 7, 2019
Here's a couple useful links related to this: |
Google have recently announced that they are going to start reporting that SSL certificates that are signed with a SHA-1 Hash will be treated as having a lower security than those signed with newer, higher strength hashes such as SHA-256 or SHA-512.
Google’s announcement can be found here at http://googleonlinesecurity.blogspot.co.uk/2014/09/gradually-sunsetting-sha-1.html
Technically at the moment there isn’t anything really wrong with the SHA-1 hash function, but it is now quite old and is starting to show potential cracks. Hence the reason that the security industry is advising to move to something better. In this case SHA-256.
1. Generate a SSL Key File
Firstly you will need to generate a key file. The example below will generate a 2048 bit key file with a SHA-256 signature.
/fable-3-cd-key-generator.html. If you want extra security you could increase the bit lengths.
Openssl Generate Rsa Key Pair
** Please note that both these examples will not add a password to the key file. To do that you will need to add -aes256 to the command.
2. Create a Certificate Signing Request (CSR)
This step will create the actually request file that you will submit to the Certificate Authority (CA) of your choice.
You can check that your Certificate Signing Request (CSR) has the correct signature by running the following.
Openssl Generate Rsa Private Key
It should display the following if the signature is correct.
3. Install the Certificate (CRT)
This step is very dependant of the software you use and I won’t really cover. All I will say is that these certificates are supported by a multitude of software, including Apache HTTPD and NGINX.
4. Test your installed Certificate
This step is extremely important and will show you any security problems with your SSL configuration.
Qualys have a free hosted service that tests the SSL configuration of Internet facing web servers for SSL issues. The sites tested are rated from A to F, and a report is generated. This report is really useful for tuning your SSL configuration.
Generate Key With Openssl
The SSL Labs tests are regularly updated when new issues are discovered. This means that if your server is rated as A today, next week it maybe rated as C.