(Objective-C) Generate a Random 256-bit AES Key and RSA Encrypt

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Generates a random 256-bit AES key and encrypts using an RSA public key. Only the owner of the RSA private key will be able to decrypt the AES key.

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#import <CkoPublicKey.h>
#import <CkoRsa.h>
#import <CkoBinData.h>
#import <CkoPrng.h>

// The RSA public key is used for encryption, and the private key for decryption.

// The public key's role is to make encryption accessible to anyone while ensuring that
// only the private key holder can decrypt the messages.
// The public key is designed to be widely distributed so anyone can use it to encrypt messages
// intended for the owner of the private key.

// Load our 2048-bit RSA public key.
CkoPublicKey *pubKey = [[CkoPublicKey alloc] init];
// In all Chilkat methods expecting a path, you pass either absolute or relative paths.
BOOL success = [pubKey LoadFromFile: @"rsaKeys/Test2048Rsa.pem"];
if (success == NO) {
    NSLog(@"%@",pubKey.LastErrorText);
    return;
}

CkoRsa *rsa = [[CkoRsa alloc] init];

// Tell RSA to use the public key.
[rsa ImportPublicKeyObj: pubKey];

// Generate a random 256-bit AES key (32 bytes)
CkoBinData *bdAesKey = [[CkoBinData alloc] init];
CkoPrng *prng = [[CkoPrng alloc] init];
[prng GenRandomBd: [NSNumber numberWithInt: 32] bd: bdAesKey];

// RSA encrypt.
[rsa EncryptBd: bdAesKey usePrivateKey: NO];

// Save the RSA encrypted AES key to a file.
success = [bdAesKey WriteFile: @"rsaEncrypted/myAes.key"];