To low to comment. I realize this but some situations still required it, for example LDAP/TLS Replication on the popular 389/RH DS. Per the Redhat Directory Server Guide V 11:
Replication configured over TLS with certificate-based authentication
fails if the supplier's certificate is only capable of behaving as a
server certificate and not also as a client ...
Anton does not need a certificate. The vaccination center needs one. It then generates a record like:
The first line contains the needed data: name, birth date, vaccination center, vaccination date and vaccine type. Next one is the signature. One can get the ...
What is shown is not the raw key bytes only but the key inside a specific container. There are various containers for an RSA key. To reproduce it on the command line:
# extract the certificate from the JKS
$ keytool -export -keystore test.jks -alias mycert -file test.cer
# extract the public key from the certificate
$ openssl x509 -in test.cer -inform der -...
While the other answers correctly point out that strictly speaking, there is no way to modify a certificate, that's not the end of the story.
A certificate comprises three components:
Name (Subject, possibly SubjectAltNames as well)
Signature binding the former two together
While there is no way to change the name without replacing the signature ...