用命令行執行下面的命令:
1.把PEM轉成PKCS12格式
openssl pkcs12 -export -out cacert.p12 -in cacert.pem
2. 把PKCS 轉成crt
openssl pkcs12 -in cacert.p12 -out mycerts.crt -nokeys -clcerts
3.把crt轉成cer
openssl x509 -inform pem -in mycerts.crt -outform der -out mycerts.cer