Fix demobench as part of network parameters work (#2148)

* Fix demobench - network parameters

Demobench uses ServiceIdentityGenerator to pregenerate notary identity
for network parameters.

node-api/src/main/kotlin/net/corda/nodeapi/internal/ServiceIdentityGenerator.kt

@@ -0,0 +1,49 @@
+package net.corda.nodeapi.internal
+
+import net.corda.core.crypto.CompositeKey
+import net.corda.core.crypto.generateKeyPair
+import net.corda.core.identity.CordaX500Name
+import net.corda.core.identity.Party
+import net.corda.core.internal.cert
+import net.corda.core.internal.createDirectories
+import net.corda.core.internal.div
+import net.corda.core.utilities.trace
+import net.corda.nodeapi.internal.crypto.*
+import org.slf4j.LoggerFactory
+import java.nio.file.Path
+
+object ServiceIdentityGenerator {
+    private val log = LoggerFactory.getLogger(javaClass)
+    /**
+     * Generates signing key pairs and a common distributed service identity for a set of nodes.
+     * The key pairs and the group identity get serialized to disk in the corresponding node directories.
+     * This method should be called *before* any of the nodes are started.
+     *
+     * @param dirs List of node directories to place the generated identity and key pairs in.
+     * @param serviceName The legal name of the distributed service.
+     * @param threshold The threshold for the generated group [CompositeKey].
+     */
+    fun generateToDisk(dirs: List<Path>,
+                       serviceName: CordaX500Name,
+                       serviceId: String,
+                       threshold: Int = 1): Party {
+        log.trace { "Generating a group identity \"serviceName\" for nodes: ${dirs.joinToString()}" }
+        val keyPairs = (1..dirs.size).map { generateKeyPair() }
+        val notaryKey = CompositeKey.Builder().addKeys(keyPairs.map { it.public }).build(threshold)
+
+        val caKeyStore = loadKeyStore(javaClass.classLoader.getResourceAsStream("certificates/cordadevcakeys.jks"), "cordacadevpass")
+        val issuer = caKeyStore.getCertificateAndKeyPair(X509Utilities.CORDA_INTERMEDIATE_CA, "cordacadevkeypass")
+        val rootCert = caKeyStore.getCertificate(X509Utilities.CORDA_ROOT_CA)
+
+        keyPairs.zip(dirs) { keyPair, dir ->
+            val serviceKeyCert = X509Utilities.createCertificate(CertificateType.CLIENT_CA, issuer.certificate, issuer.keyPair, serviceName, keyPair.public)
+            val compositeKeyCert = X509Utilities.createCertificate(CertificateType.CLIENT_CA, issuer.certificate, issuer.keyPair, serviceName, notaryKey)
+            val certPath = (dir / "certificates").createDirectories() / "distributedService.jks"
+            val keystore = loadOrCreateKeyStore(certPath, "cordacadevpass")
+            keystore.setCertificateEntry("$serviceId-composite-key", compositeKeyCert.cert)
+            keystore.setKeyEntry("$serviceId-private-key", keyPair.private, "cordacadevkeypass".toCharArray(), arrayOf(serviceKeyCert.cert, issuer.certificate.cert, rootCert))
+            keystore.save(certPath, "cordacadevpass")
+        }
+        return Party(serviceName, notaryKey)
+    }
+}