Useful openssl commands
View certificate attributes, such as common name (domain name), subject alternate name, issued by, expiry date, issued to, etc.
openssl x509 -in cert.crt -noout -text
Check certificate and key match (no output indicates a match):
diff < (openssl x509 -in certificate.crt -noout -modulus) <(openssl rsa -in privatekey.key -noout -modulus)
Manually check certificate and key match
openssl x509 -in certificate.crt -noout -modulus openssl rsa -in privatekey.key -noout -modulus
If the resultant strings match, the certificate and key match.
Here is a another way which results in a smaller output to compare:
openssl x509 -in certificate.crt -noout -modulus|openssl md5 openssl rsa -in privatekey.key -noout -modulus|openssl md5
Sample output:
$ openssl x509 -in certificate.crt -noout -modulus|openssl md5 9fd6d809335574aa474037952ac485aa $ openssl rsa -in privateKey.key -noout -modulus|openssl md5 9fd6d809335574aa474037952ac485aa