RC4 in Swift

rc4.swift

func RC4(🔏:[UInt8], 🔑:[Int]) -> [UInt8]
{
    var i = 0, j = 0, S = Array(0...255)
    for i in 0...255 {
        j = (j + S[i] + 🔑[i % 🔑.count]) % 256
        (S[j], S[i]) = (S[i], S[j])
    }
    i = 0; j = 0
    return 🔏.map {
        i = (i + 1) % 256; j = (j + S[i]) % 256
        (S[j], S[i]) = (S[i], S[j])
        return $0 ^ UInt8(S[(S[i] + S[j]) % 256])
    }
}