Can an SSL certificate be signed by two issuers at the same time?
Let's take an intermediate certificate as an example.
It is usually signed by a root. A root certificate is often self-signed. In my understanding, if we take cross-signing, there are usually two or more certificate sets as we have several intermediate or root variations signed by different roots.
I have never seen a certificate signed by several issuers at the same time in practice. Is it possible?
P.S. I found the answer here: https://superuser.com/questions/477426/certificates-signed-by-multiple-cas
https://superuser.com/questions/1013159/is-it-possible-to-have-a-certificate-signed-by-2-authorities
No, it's not possible for an X.509 certificate (the type used by OpenSSL) to have more than one signature.
