ClientIdentityController.m

// Excerpt from sample project located here: 
// https://developer.apple.com/library/content/samplecode/AdvancedURLConnections/Introduction/Intro.html

+ (NSArray *)_identities
    // Returns an array of SecIdentityRef that represents the available client-side 
    // identities in the keychain.
    //
    // We go /back/ to the keychain to get the list of identities rather than 
    // using the Credentials module.  This decouples this class from the program 
    // as a whole, making it easier for folks to reuse it.  OTOH, if the client 
    // wants to use an alternative identity source, it can implement the 
    // -identityViewIdentitiesToDisplay: delegate callback.
{
    OSStatus        err;
    NSArray *       result;
    CFArrayRef      identities;

    identities = NULL;
    
    err = SecItemCopyMatching(
        (CFDictionaryRef) [NSDictionary dictionaryWithObjectsAndKeys:
            (id) kSecClassIdentity,     kSecClass, 
            kSecMatchLimitAll,          kSecMatchLimit, 
            kCFBooleanTrue,             kSecReturnRef, 
            nil
        ],
        (CFTypeRef *) &identities
    );
    if (err == noErr) {
        result = [NSArray arrayWithArray:(id) identities];
    } else {
        result = [NSArray array];
    }
    
    if (identities != NULL) {
        CFRelease(identities);
    }
    
    return result;
}

/*
    File:       ClientIdentityController.m

    Contains:   Runs an HTTPS client identity choice view.

    Written by: DTS

    Copyright:  Copyright (c) 2011 Apple Inc. All Rights Reserved.

    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.
                ("Apple") in consideration of your agreement to the following
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                redistribution of this Apple software constitutes acceptance of
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                not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following
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                non-exclusive license, under Apple's copyrights in this
                original Apple software (the "Apple Software"), to use,
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                without modifications, you must retain this notice and the
                following text and disclaimers in all such redistributions of
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                or logos of Apple Inc. may be used to endorse or promote
                products derived from the Apple Software without specific prior
                written permission from Apple.  Except as expressly stated in
                this notice, no other rights or licenses, express or implied,
                are granted by Apple herein, including but not limited to any
                patent rights that may be infringed by your derivative works or
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                The Apple Software is provided by Apple on an "AS IS" basis. 
                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
                WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,
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                THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
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*/