информация

openssl x509 -in cert.pem -text -noout

Даты

openssl x509 -in cert.pem -dates -noout

Дата окончания

openssl x509 -in cert.pem -enddate-noout

openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout selfsigned.key -out selfsigned.crt

openssl x509 -inform der -in certificate.cer -out certificate.pem

openssl pkcs12 -export -out selfsigned.pfx -inkey selfsigned.key -in selfsigned.crt

Экстрагируем сертификат:

openssl pkcs12 -in [yourfile.pfx] -clcerts -nokeys -out [certificate.crt]

Получаем RSA ключ с паролем

openssl pkcs12 -in [yourfile.pfx] -nocerts -out [keyfile-encrypted.key]

Получаем RSA ключ без пароля:

openssl rsa -in [keyfile-encrypted.key] -out [keyfile-decrypted.key]

echo | openssl s_client -connect [ip-or-host]:443 -servername [host] 2>/dev/null | openssl x509 -noout -enddate

 openssl s_client -connect [ip-or-host]:25 -CAfile CA-cert.pem -starttls smtp | openssl x509 -enddate -noout