Hi Neil,
You can generate the key by using the following command
keytool.exe -genkey -v -keystore file.keystore -alias nativeapp -storepass pass@123 -keypass pass@123 -keyalg RSA -validity 365000
then , use this below command to get the fingerprint
keytool -list -v -keystore file.keystore -alias nativeapp -storepass pass@123 -keypass pass@123
Note: Execute this command in java /jdk/bin folder
I hope it helps.