iphone - 将 SecKeyRef（公钥）转换为 NSString

Question

我正在使用在磁盘上保存 SecKeyRef 设备生成的公钥/私钥对这个例子，但是我在 sanityCheck 中不断得到 -25300。谁能告诉我出了什么问题或这个错误意味着什么？谢谢

SecKeyRef 公钥；SecKeyRef 私有密钥；

CFDictionaryRef keyDefinitions;
CFTypeRef keys[2];
CFTypeRef values[2];

keys[0] = kSecAttrKeyType;
values[0] = kSecAttrKeyTypeRSA;

keys[1] = kSecAttrKeySizeInBits;
int iByteSize = 2048;
values[1] = CFNumberCreate(NULL, kCFNumberIntType, &iByteSize);

keyDefinitions = CFDictionaryCreate(NULL, keys, values, sizeof(keys) / sizeof(keys[0]), NULL,NULL );

OSStatus status = SecKeyGeneratePair(keyDefinitions,&publicKey, &privateKey);
status = SecItemCopyMatching((CFDictionaryRef)publicKey, (CFTypeRef *)&publicKeyBits);//<--where error occur.