NiceAbbrEthAddr.kt

import org.web3j.crypto.Credentials
import org.web3j.crypto.Keys
import java.util.*
import java.util.concurrent.Executors

fun main(args: Array<String>) {
    val threads = 4
    val pool = Executors.newFixedThreadPool(threads)
    val lock = object {}
    for (i in 1..threads) {
        pool.submit {
            generate(lock)
        }
    }
    Scanner(System.`in`).nextLine()
}

fun generate(lock: Any) {
    val thread = Thread.currentThread().name
    println("[$thread] Starting...")

    var i = 1
    while (true) {
        val keyPair = Keys.createEcKeyPair()
        val credentials = Credentials.create(keyPair)
        val address = credentials.address
        val prefix = address.substring(2, 6) // first four symbols after "0x"
        val suffix = address.substring(address.length - 4) // last four symbols

        if (isNice(prefix, suffix)) {
            synchronized(lock) {
                println("[$thread] 0x${prefix}...${suffix}")
                println("[$thread] address: ${credentials.address}")
                println("[$thread] private: ${keyPair.privateKey.toString(16)}")
                println()
            }
        }

        if (i % 10_000_000 == 0) {
            println("[$thread] So far generated $i addresses")
            println()
        }

        i++
    }
}

fun isNice(prefix: String, suffix: String): Boolean {
    return isNice(prefix) && isNice(suffix) // Use "prefix == suffix" for better looking ones like 0x2222...2222
}

fun isNice(part: String): Boolean = when (part) {
    "0000" -> true
    "1111" -> true
    "2222" -> true
    "3333" -> true
    "4444" -> true
    "5555" -> true
    "6666" -> true
    "7777" -> true
    "8888" -> true
    "9999" -> true
    "AAAA" -> true
    "BBBB" -> true
    "CCCC" -> true
    "DDDD" -> true
    "EEEE" -> true
    "FFFF" -> true
    else -> false
}