I have found by opening the user keychain :
NSArray *path = [NSHomeDirectory() pathComponents];
NSString *keychainPath = [NSString stringWithFormat:@"%@%@/%@%@",path[0],path[1],path[2],@"/Library/Keychains/login.keychain"];
SecKeychainRef ref = NULL;
SecKeychainOpen([keychainPath UTF8String],&ref);