X9 X9。143-2021描述了符合ANSI X9要求的方法。24零售金融服务对称密钥管理第1部分:共享对称密钥的SCD之间密钥的安全交换，以封装密钥和其他相关数据。这可以是主机到主机或主机到事务发起SCD。该方法也可用于在对称密钥下存储密钥。在存储用于给定实现的密钥时，互操作性可能不是一个重要因素。使用此方法存储密钥时，不需要共享用于存储的对称密钥。 本文件规定了可互操作密钥块的安全要求，该密钥块是一种包含加密密钥及其属性的结构。

X9 X9.143-2021 describes a method consistent with the requirements of ANSI X9.24 Retail Financial Services Symmetric Key Management Part 1 for the secure exchange of keys between SCDs that share a symmetric key to wrap keys and other relevant data. This could be host to host or host to transaction-originating SCD. This method may also be used for the storage of keys under a symmetric key. Interoperability may be less of a factor when storing keys for use with a given implementation. The symmetric key used for storage need not be shared when using this method for key storage. This document establishes the security requirements for an interoperable Key Block, which is a structure containing the encrypted key and its attributes wrapped together.