PEM 格式证书
openssl x509 -in /path/to/cert.crt -noout -modulus
DER 格式证书
openssl x509 -in /path/to/cert.der -inform der -noout -modulus
openssl x509 -in /path/to/cert.crt -noout -modulus
openssl x509 -in /path/to/cert.der -inform der -noout -modulus