``` private val hexArray = CharArray(16) { if (it ...

# stdlib

[marcinmoskala]

private val hexArray = CharArray(16) { if (it < 10) '0' + it else 'a' + (it - 10) }
fun ByteArray.toHexString(): String {
    val builder = StringBuilder(size * 2)
    for (byte in this) {
        val v = byte.toInt() and 0xFF
        builder.append(hexArray[v.ushr(4)])
        builder.append(hexArray[v and 0x0F])
    }
    return builder.toString()
}

Implementation a bit slower, but multiplatform