Objective-C

RSA Encrypt Randomly Generated AES Key

See more RSA Examples

Demonstrates how to RSA encrypt a randomly generated AES key. Objective-C

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

BOOL success = NO;

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

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

//  Use a public key from a certificate for RSA encryption.
CkoCert *cert = [[CkoCert alloc] init];

success = [cert LoadFromFile: @"qa_data/pem/mf_public_rsa.pem"];
if (success == NO) {
    NSLog(@"%@",cert.LastErrorText);
    return;
}

CkoPublicKey *pubKey = [[CkoPublicKey alloc] init];
[cert GetPublicKey: pubKey];

CkoRsa *rsa = [[CkoRsa alloc] init];
success = [rsa UsePublicKey: pubKey];
if (success == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

//  RSA encrypt our 32-byte AES key.
//  The contents of bdAesKey are replaced with result of the RSA encryption.
success = [rsa EncryptBd: bdAesKey usePrivateKey: NO];
if (success == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

//  Return the result as a base64 string
NSString *encryptedAesKey = [bdAesKey GetEncoded: @"base64"];

NSLog(@"%@%@",@"encrypted AES key = ",encryptedAesKey);