NONE：这一级别的传输保证不使用SSL，允许数据照常传输。

NONE: This transport guarantee level does not apply SSL, and lets the data transport happen as usual.

youdao

CONFIDENTIAL：这个传输保证用于满足内容私密性的要求。

Confidential: This transport guarantee is used to establish a requirement for confidentiality part of the content.

youdao

必需的防护力度是由传输保证（transport guarantee）元素的值来定义。

The strength of the required protection is defined by the value of the transport guarantee. Following are the values defined in TransportGuarantee inner class

youdao