Loading a X509 pem certificate with password. Objective C - ios

Question

i'm a totally newbie in objective-c and iOS programming.
I need to use a REST API, in which the request requires a mutual SSL authentication with a x509 PEM certificate file and a password for the certificate.
My problem is that i don't really know how to do it in objective C, in C# it would be as easy as:
X509Certificate2 myCertificate = new x509Certificate2(certificatePath, certificatePassword);
myRequest.ClientCertificate.Add(myCertificate);
Where "myRequest" just represents the variable of the http request.
I've been looking for a while in many forums and posts, including some old stackoverflow questions.
The main tip people give is "use OpenSSL", but i've read in few places (i think even in a stackoverflow question) that Apple has deprecated OpenSSL.
Question: How could i load a .pem x509 certificate with its password to send in a POST request to a external REST API Service, in objective-C language?
Thank you.

Answer 1

My Own Solution:
Using OpenSSL command to convert .pem file intro pkcs12 certificate:
openssl pkcs12 -export -in "certificateFile" -inkey "KeyFile" -out "certificate.p12"
Then setting up some code found in this tutorial: https://vanjakom.wordpress.com/tag/nsurlconnection/
Basically:
- (void)connection:(NSURLConnection *)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge
{
NSLog(#"Authentication challenge");
// load cert
NSString *path = [[NSBundle mainBundle] pathForResource:#"userA" ofType:#"p12"];
NSData *p12data = [NSData dataWithContentsOfFile:path];
CFDataRef inP12data = (__bridge CFDataRef)p12data;
SecIdentityRef myIdentity;
SecTrustRef myTrust;
OSStatus status = extractIdentityAndTrust(inP12data, &myIdentity, &myTrust);
SecCertificateRef myCertificate;
SecIdentityCopyCertificate(myIdentity, &myCertificate);
const void *certs[] = { myCertificate };
CFArrayRef certsArray = CFArrayCreate(NULL, certs, 1, NULL);
NSURLCredential *credential = [NSURLCredential credentialWithIdentity:myIdentity certificates:(__bridge NSArray*)certsArray persistence:NSURLCredentialPersistencePermanent];
[[challenge sender] useCredential:credential forAuthenticationChallenge:challenge];
}
And
OSStatus extractIdentityAndTrust(CFDataRef inP12data, SecIdentityRef *identity, SecTrustRef *trust)
{
OSStatus securityError = errSecSuccess;
CFStringRef password = CFSTR("userA");
const void *keys[] = { kSecImportExportPassphrase };
const void *values[] = { password };
CFDictionaryRef options = CFDictionaryCreate(NULL, keys, values, 1, NULL, NULL);
CFArrayRef items = CFArrayCreate(NULL, 0, 0, NULL);
securityError = SecPKCS12Import(inP12data, options, &items);
if (securityError == 0) {
CFDictionaryRef myIdentityAndTrust = CFArrayGetValueAtIndex(items, 0);
const void *tempIdentity = NULL;
tempIdentity = CFDictionaryGetValue(myIdentityAndTrust, kSecImportItemIdentity);
*identity = (SecIdentityRef)tempIdentity;
const void *tempTrust = NULL;
tempTrust = CFDictionaryGetValue(myIdentityAndTrust, kSecImportItemTrust);
*trust = (SecTrustRef)tempTrust;
}
if (options) {
CFRelease(options);
}
return securityError;
}
"Code copied from the tutorial, did not copy my own modification for my own needs".
And it's solved