To publish an application to Google Play, you need to export and download the key from Java Keystore.
I executed the specified command and got encryption_public_key.pem:
keytool -export -rfc -keystore upload-keystore.jks -alias upload -file upload_certificate.pem
After that I executed the command: java -jar pepk.jar --keystore=foo.keystore --alias=foo --output=output.zip --include-cert --rsa-aes-encryption --encryption-key-path=/path/to/encryption_public_key.pem
And got an error (https://i.stack.imgur.com/QovjD.png)
Error when exporting the key for Google Play