[ETCM-411] Add optional param to generate more keys at once

Author: KonradStaniec

src/main/scala/io/iohk/ethereum/crypto/EcKeyGen.scala

@@ -3,19 +3,24 @@ package io.iohk.ethereum.crypto
 import io.iohk.ethereum.nodebuilder.SecureRandomBuilder
 
 /**
-  * A simple tool to generate and ECDSA key pair. The key pair will be printed in the format:
+  * A simple tool to generate ECDSA key pairs. Takes an optional positional argument [n] - number of key pairs
+  * to generate (default is 1).
+  * The key pairs will be printed in the format:
   *   priv-key-hex (32 bytes)
   *   pub-key-hex (64 bytes)
   *
   * Run:
-  *   ./eckeygen > mantis-datadir/node.key
+  *   ./eckeygen [n] > mantis-datadir/node.key
   *
   * to generate the private key for the node. Note that only the private key will be read upon Mantis boot,
   * and the second line is equivalent to node ID.
   * The tool can also be used to generate keys for an Ethereum account.
   */
 object EcKeyGen extends App with SecureRandomBuilder {
-  val (prv, pub) = newRandomKeyPairAsStrings(secureRandom)
+  val numOfKeys = args.headOption.map(_.toInt).getOrElse(1)
+
+  val keyPairs = for (_ <- 1 to numOfKeys) yield newRandomKeyPairAsStrings(secureRandom)
+
   //scalastyle:off
-  println(prv + "\n" + pub)
+  println(keyPairs.map { case (prv, pub) => s"$prv\n$pub\n" }.mkString("\n"))
 }