(Swift 2) Generating Repeatable Random Data for Testing/Debugging

Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging.

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // All Chilkat classes can be unlocked at once at the beginning of a program
    // by calling UnlockBundle.  It requires a Bundle unlock code.
    let chilkatGlob = CkoGlobal()
    var success: Bool = chilkatGlob.UnlockBundle("Anything for 30-day trial.")
    if success != true {
        print("\(chilkatGlob.LastErrorText)")
        return
    }

    let fortuna = CkoPrng()

    // Normally an application would seed the PRNG with entropy from
    // some real random source.  However, sometimes we want the same
    // random sequence of bytes for testing and debugging purposes.
    // This a reason why GetEntropy and AddEntropy are two different methods.
    // An application could omit the call to GetEntropy, and instead pass
    // non-random data to AddEntropy. For example:

    // Seed the PRNG with non-entropy, so we get a repeatable sequence.
    // Note: AddEntropy can be called any number of times.
    success = fortuna.AddEntropy("01020304", encoding: "hex")
    success = fortuna.AddEntropy("hello world", encoding: "ascii")

    // Generate some random data:
    var strRandHex: String? = fortuna.GenRandom(16, encoding: "hex")
    var strRandBase64: String? = fortuna.GenRandom(22, encoding: "base64")
    var strRandBase58: String? = fortuna.GenRandom(32, encoding: "base58")

    print("hex random bytes: \(strRandHex!)")
    print("base64 random bytes: \(strRandBase64!)")
    print("base58 random bytes: \(strRandBase58!)")

    // Try it again with a different object to verify that the same results are obtained:
    let fortuna2 = CkoPrng()

    success = fortuna2.AddEntropy("01020304", encoding: "hex")
    success = fortuna2.AddEntropy("hello world", encoding: "ascii")

    strRandHex = fortuna2.GenRandom(16, encoding: "hex")
    strRandBase64 = fortuna2.GenRandom(22, encoding: "base64")
    strRandBase58 = fortuna2.GenRandom(32, encoding: "base58")

    print("hex random bytes: \(strRandHex!)")
    print("base64 random bytes: \(strRandBase64!)")
    print("base58 random bytes: \(strRandBase58!)")

}