Note: 强烈不推荐在线上版本中使用。请使用服务器获取签名的模式来使用签名。如果您使用改类，请配合临时密钥CAM服务使用。

示例

@code

QCloudCredential* credential = [QCloudCredential new];
credential.secretID = kSecretIDCSP;
credential.secretKey = kSecretKeyCSP;
credential.experationDate = [NSDate dateWithTimeIntervalSince1970:1504183628];
QCloudAuthentationV5Creator* creator = [[QCloudAuthentationV5Creator alloc] initWithCredential:credential];
QCloudSignature* signature =  [creator signatureForData:urlRequst];