在Objective-C中使用NSLog打印SecKeyRef参考

我使用下面的代码从证书中检索公钥。

- (SecKeyRef) extractPublicKeyFromCertificate: (SecIdentityRef) identity { // Get the certificate from the identity. SecCertificateRef myReturnedCertificate = NULL; OSStatus status = SecIdentityCopyCertificate (identity, &myReturnedCertificate); if (status) { NSLog(@"SecIdentityCopyCertificate failed.\n"); return NULL; } SecKeyRef publickey; SecCertificateCopyPublicKey(myReturnedCertificate, &publickey); NSLog(@"%@", publickey); return publickey; } 

我正在试图打印“publickey”variables来查看内容。 我得到运行时错误。 我想知道如何打印“publickey”variables的内容？