Vigenère cipher: Difference between revisions

=={{header|Kotlin}}==

<lang scala>// version 1.1.3

fun vigenere(text: String, key: String, encrypt: Boolean = true): String {

val t = if (encrypt) text.toUpperCase() else text

val sb = StringBuilder()

var ki = 0

for (c in t) {

if (c !in 'A'..'Z') continue

val ci = if (encrypt)

(c.toInt() + key[ki].toInt() - 130) % 26

else

(c.toInt() - key[ki].toInt() + 26) % 26

sb.append((ci + 65).toChar())

ki = (ki + 1) % key.length

}

return sb.toString()

}

fun main(args: Array<String>) {

val key = "VIGENERECIPHER"

val text = "Beware the Jabberwock, my son! The jaws that bite, the claws that catch!"

val encoded = vigenere(text, key)

println(encoded)

val decoded = vigenere(encoded, key, false)

println(decoded)

}</lang>

{{out}}

<pre>

WMCEEIKLGRPIFVMEUGXQPWQVIOIAVEYXUEKFKBTALVXTGAFXYEVKPAGY

BEWARETHEJABBERWOCKMYSONTHEJAWSTHATBITETHECLAWSTHATCATCH

</pre>