topic Re: How to create a self signed certificate with openssl? in Spark Firewall (SMB)

How to create a self signed certificate with openssl?

LM-Rafael — Mon, 24 Feb 2025 21:34:50 GMT

Hello everyone,

I'm trying to create a self-signed certificate using OpenSSL, but I keep running into an issue where the certificate is recognized as invalid.

I followed these steps to create the certificate:

Generating the Private Key
openssl genrsa -out my_private.key 2048
Creating the Certificate Signing Request (CSR)
openssl req -new -key my_private.key -out my_request.csr
I filled in the required details like Common Name (CN), organization, and location.
Creating the Self-Signed Certificate
openssl x509 -req -in my_request.csr -signkey my_private.key -out my_certificate.crt -days 365 -sha256
Converting to PFX for Import
openssl pkcs12 -export -out my_certificate.pfx -inkey my_private.key -in my_certificate.crt -passout pass:MySecurePassword

Everything seems to be correct, but when I try to use the certificate, my system or application says it is invalid.

I checked the certificate details with:

openssl x509 -in my_certificate.crt -noout -text

The output seems fine, but it still doesn’t work.

Could the issue be related to a missing CA certificate, incorrect signing, or something else in my OpenSSL setup?

I’d really appreciate any help or advice on what could be causing this. Has anyone else experienced this problem?

Thanks in advance!

Rafael

Re: How to create a self signed certificate with openssl?

Lesley — Mon, 24 Feb 2025 21:50:27 GMT

Maybe it is a stupid comment. But for me it is normal an application / browser will give a warning because it is self-signed.

And with system you mean a Check Point device? Because I don't see how it is related yet.

Re: How to create a self signed certificate with openssl?

LM-Rafael — Mon, 24 Feb 2025 22:04:17 GMT

Sry.

I want to upload the self-signed certificate to my 1600 appliance. But i get from the appliance web interface the error message: "Invalid Certificate or Password is Wrong". But the Password is correct!

Re: How to create a self signed certificate with openssl?

the_rock — Tue, 25 Feb 2025 01:37:05 GMT

Maybe wrong cert extension?

Andy

Re: How to create a self signed certificate with openssl?

the_rock — Tue, 25 Feb 2025 01:51:14 GMT

Reason @LM-Rafael why I asked last question about extension of the cert is because whenever you try to upload any sort of cert, regardless if its for the fw or anything else, it will always come up with predefined (for the lack of the better word) extension, so say if you see .p12 there, then certificate HAS TO be in that format, nothing else would work.

Hope that helps.

Andy