ls android/build/target/product/security
Android.mk media.x509.pem platform.x509.pem releasekey.x509.pem shared.x509.pem testkey.x509.pem verity.pk8
media.pk8 platform.pk8 README shared.pk8 testkey.pk8 verity_key verity.x509.pem
以常用的platform签名为例：
openssl pkcs8 -inform DER -nocrypt -in platform.pk8 -out platform.pem
openssl pkcs12 -export -in platform.x509.pem -out platform.p12 -inkey platform.pem -password pass:android -name androiddebugkey
keytool -importkeystore -deststorepass android -destkeystore ./platform.keystore -srckeystore ./platform.p12 -srcstoretype PKCS12 -srcstorepass android
最终的platform.keystore即为我们所要的keystore
