I recent tried to use PHP openssl extension with an ecdsa self signed certificate that i've issued using this tutorial create-a-self-signed-ecc-certificate. I have used function openssl_sign() as described in PHP manual. I've notice every time i refresh the web page , i got different signature output. Can anyone explain what happen? And is there any manner to get the same signature output every time with ecdsa certificate?
A component of generating an ECDSA signature is generating a random number (k).
Since each call to sign will generate a distinct random number, there's no way to produce a deterministic certificate with ECDSA (aside from doing all of the ECC math yourself, and choosing k; or finding a library somewhere which lets k be specified).