生成Query鉴权签名：

1. 计算StringToSign:
					
StringToSign = HTTP-Verb + "\n" + 
Content-MD5 + "\n" + 
Content-Type + "\n" + 
Expires + "\n" + 
CanonicalizedHeaders + 
CanonicalizedResource
							
2. 计算Signature:
					
Signature = 
UrlEncode(Base64(Hmac-sha1(SK, UTF-8-Encoding-Of(StringToSign))))

3. 计算签名Url中的Query
SignedUrlQuery =
?AccessKeyId=AK&Expires=Expires&Signature=Signature[&x-obs-security-token=securityToken]
：