OfflineGenerateHash.kt

fun main(args: Array<String>) {

    val digest = MessageDigest.getInstance("SHA-256")

    args.forEach { digest.update(it.toLowerCase().toByteArray(Charset.forName("UTF-8"))) }

    println(digest.digest().toHexString())
}

/**
 *  Set of chars for a half-byte.
 */
private val CHARS = arrayOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f')

/**
 *  Returns the string of two characters representing the HEX value of the byte.
 */
internal fun Byte.toHexString(): String {
    val i = this.toInt()
    val char2 = CHARS[i and 0x0f]
    val char1 = CHARS[i shr 4 and 0x0f]
    return "$char1$char2"
}

/**
 *  Returns the HEX representation of ByteArray data.
 */
internal fun ByteArray.toHexString(): String {
    val builder = StringBuilder()
    for (b in this) {
        builder.append(b.toHexString())
    }
    return builder.toString()
}