I finally found the answer. I was supposed to use SecIdentityCopyCertificate(identity, &certificateRef); instead of SecCertificateCreateWithData(nil, inPKCS12Data); to create my certificate.

I tried your updated code with the addition of two lines at the end:

NSData *cipherData = [NSData dataWithBytes:aCipherText length:iCipherLength];
NSLog(@"(%d) %@", status, cipherData);

That works fine:

2011-02-17 22:24:04.204 Untitled[45121:207] (0) <87a2eb07 25ab693a 7fe88329 974b6820
843c5c33 8c5d4606 aecea682 0176e4cb 10482c9b fd2e2242 1c77d349 d3037e91 8d704783
f2e04c82 ef273815 bdb6aa73 f8646542 243f3e12 518147ba 53636441 fd9399d3 b198ed6a
615d51d1 4105fb75 27180f0d 09835551 5162e156 33dedf39 a87e17f8 16881990 c5e57a38
7cd7ec63>

Now one difference is that the public key I'm using is in my keychain. If yours isn't, you may want to look at the importing-an-ssl-cert-under-the-iphone-sdk link below. So far I've only tested on Simulator, which also can be different, but I believe this is correct.

If you still have trouble, make sure to check the result of each call (and if it returns OSStatus, check that). Which piece is failing?

You forgot to call SecTrustEvaluate() on your SecTrustRef before calling SecTrustCopyPublicKey(). Check the docs on SecTrustCopyPublicKey() which explains this.

Old information that wasn't as useful:

I believe these posts should point you in the right direction:

http://greghaygood.com/2009/01/17/asymmetric-encryption-with-the-iphone-sdk-and-securityframework

Importing an SSL cert under the iPhone SDK

Also note that if you have OpenSSL code for Mac already, you can compile OpenSSL for iPhone. This post was useful for me when I developed my build scripts:

http://www.therareair.com/2009/01/01/tutorial-how-to-compile-openssl-for-the-iphone/

For mac:

let pubKey = "-----BEGIN PUBLIC KEY-----MIICIjANBgAgK.......InbFk1FkucQqruMyUCAwEAAQ==-----END PUBLIC KEY-----"
let pubKeyData = pubKey.dataUsingEncoding(NSASCIIStringEncoding)
var error: Unmanaged<CFErrorRef>?
let secKey = SecKeyCreateFromData(NSDictionary(), pubKeyData!, &error)

Where pubKey is a string representation of your public key. If you don't know your public key, you can infer it from your private key with the following command:

openssl rsa -in server.key -pubout  > mykey.pub

Where server.key is the file containing -----BEGIN RSA PRIVATE KEY----- as the first line.

For iOS:

It's a bit more complicate. You need a der file. It's a binary representation of your certificate. If you need to convert an existing certificate, you can do so with the following command:

 openssl x509 -outform der -in file.crt|pem -out mycert.der

The .crt or .pem file contains -----BEGIN CERTIFICATE----- as the first line.

Put the der file in your bundle and do:

let certificateData = NSData(contentsOfURL:NSBundle.mainBundle().URLForResource("mycert", withExtension: "der")!)

let certificate = SecCertificateCreateWithData(nil, certificateData!)

var trust: SecTrustRef?

let policy = SecPolicyCreateBasicX509()
let status = SecTrustCreateWithCertificates(certificate!, policy, &trust)

if status == errSecSuccess {
    let key = SecTrustCopyPublicKey(trust!)!;
}

Yatta ! Key now contains a SecKey representation of your public key. Happy Pinning.

Your missing iOS frameworks in the project. I bet security framework is one of them from the names I see.

Have you added all the correct frameworks outlined at http://developer.inmobi.com/wiki/index.php?title=IOS.

It looks like you might not have linked the Security framework specifically?