(Objective-C) 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.

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#import <CkoGlobal.h>
#import <CkoPrng.h>
#import <NSString.h>

// All Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
CkoGlobal *chilkatGlob = [[CkoGlobal alloc] init];
BOOL success = [chilkatGlob UnlockBundle: @"Anything for 30-day trial."];
if (success != YES) {
    NSLog(@"%@",chilkatGlob.LastErrorText);
    return;
}

CkoPrng *fortuna = [[CkoPrng alloc] init];

// 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:
NSString *strRandHex = [fortuna GenRandom: [NSNumber numberWithInt: 16] encoding: @"hex"];
NSString *strRandBase64 = [fortuna GenRandom: [NSNumber numberWithInt: 22] encoding: @"base64"];
NSString *strRandBase58 = [fortuna GenRandom: [NSNumber numberWithInt: 32] encoding: @"base58"];

NSLog(@"%@%@",@"hex random bytes: ",strRandHex);
NSLog(@"%@%@",@"base64 random bytes: ",strRandBase64);
NSLog(@"%@%@",@"base58 random bytes: ",strRandBase58);

// Try it again with a different object to verify that the same results are obtained:
CkoPrng *fortuna2 = [[CkoPrng alloc] init];

success = [fortuna2 AddEntropy: @"01020304" encoding: @"hex"];
success = [fortuna2 AddEntropy: @"hello world" encoding: @"ascii"];

strRandHex = [fortuna2 GenRandom: [NSNumber numberWithInt: 16] encoding: @"hex"];
strRandBase64 = [fortuna2 GenRandom: [NSNumber numberWithInt: 22] encoding: @"base64"];
strRandBase58 = [fortuna2 GenRandom: [NSNumber numberWithInt: 32] encoding: @"base58"];

NSLog(@"%@%@",@"hex random bytes: ",strRandHex);
NSLog(@"%@%@",@"base64 random bytes: ",strRandBase64);
NSLog(@"%@%@",@"base58 random bytes: ",strRandBase58);