SecKeyRef publicKeyReference = NULL;
NSMutableDictionary* queryPublicKey;
SecItemCopyMatching((CFDictionaryRef)queryPublicKey, (CFTypeRef *)&publicKeyReference);
publicKeyReference - 是您的公钥表示;queryPublicKey - 是您的证书表示;SecItemCopyMatching - 允许您从证书中检索公钥的功能!