Generate Key pair sample

genKey.m

- (void)generateKeyAsync:(NSString *)keyName {
    CFErrorRef error = NULL;
    SecAccessControlRef sacObject;

    // Should be the secret invalidated when passcode is removed? If not then use `kSecAttrAccessibleWhenUnlocked`.
    sacObject = SecAccessControlCreateWithFlags(kCFAllocatorDefault,
            kSecAttrAccessibleWhenPasscodeSetThisDeviceOnly,
            kSecAccessControlTouchIDAny | kSecAccessControlPrivateKeyUsage, &error);

    // Create parameters dictionary for key generation.
    NSDictionary *parameters = @{
            (id) kSecAttrTokenID: (id) kSecAttrTokenIDSecureEnclave,
            (id) kSecAttrKeyType: (id) kSecAttrKeyTypeECSECPrimeRandom,
            (id) kSecAttrKeySizeInBits: @256,
            (id) kSecAttrLabel: keyName,
            (id) kSecPrivateKeyAttrs: @{
                    (id) kSecAttrAccessControl: (__bridge_transfer id) sacObject,
                    (id) kSecAttrIsPermanent: @YES,
            }
    };

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        // Generate key pair.
        NSError *gen_error = nil;


        id privateKey = CFBridgingRelease(SecKeyCreateRandomKey((__bridge CFDictionaryRef) parameters, (void *) &gen_error));
        id publicKey = CFBridgingRelease(SecKeyCopyPublicKey((SecKeyRef)privateKey));
        if (privateKey != nil) {
            // use the private key in your code
            NSString *message = [NSString stringWithFormat:@"Key: %@ was successfully generated!", keyName];
            NSLog(message);
        } else {
            NSString *message = [NSString stringWithFormat:@"Key generation error: %@ for key: %@", gen_error, keyName];
            NSLog(message);
        }
    });

}