信息技术.安全技术.密钥管理.第4部分:基于弱机密的机制

[中文适用范围]： ISO/IEC 11770 的这一部分定义了基于弱秘密的密钥建立机制，即，可以容易地被人类记忆的秘密，因此将从相对较小的可能性集合中选择的秘密。 它指定了专门设计用于基于源自记忆密码的弱秘密建立一个或多个秘密密钥的加密技术，同时防止与弱秘密相关的离线暴力攻击。 更具体地说，这些机制旨在实现以下三个目标之一。 1）平衡密码验证密钥协商：在共享公共弱秘密的两个实体之间建立一个或多个共享秘密密钥。 在平衡密码认证密钥协商机制中，共享密钥是两个实体之间数据交换的结果，当且仅当两个实体使用相同的弱秘密且两者都没有使用时，共享密钥才会建立。 两个实体可以预先确定共享密钥的值。 2)增强的密码认证密钥协商：在两个实体A和B之间建立一个或多个共享密钥，其中A具有弱秘密，6具有从A的弱秘密的单向函数导出的验证数据。 在增强密码认证密钥协商机制中，共享密钥是两个实体之间数据交换的结果，当且仅当两个实体使用了弱秘密和相应的验证数据时，共享密钥才被建立，并且两个实体都不能预先确定共享密钥的值。 注意 - 这种类型的密钥协商机制无法保护 A 的弱秘密被 6 发现，而只会增加对手从 6 获取 A 的弱秘密的成本。 因此，它通常在客户端 (A) 和服务器之间使用（6）。 3) 密码验证密钥检索：为与另一个实体 6 关联的实体 A 建立一个或多个秘密密钥，其中 A 具有弱秘密，B 具有与 A 的弱秘密相关联的强秘密。 在经过身份验证的密钥检索机制中，可由 A 检索（不一定可由 6 导出）的秘密密钥是两个实体之间数据交换的结果，并且当且仅当两个实体使用弱秘密和相关的强秘密。 然而，尽管B的强秘密与A的弱秘密相关联，但是强秘密（其本身）不包含足够的信息来允许确定弱秘密或在机制中建立的秘密密钥。 注 - 这种类型的密钥检索机制用于 A 没有安全存储强秘密并且需要 B 帮助为她检索强秘密的应用程序。 它通常用在客户端 (A) 和服务器 (6) 之间。 ISO/IEC 11770 的这一部分不涵盖密钥管理的各个方面，例如：弱秘密、强秘密和既定秘密密钥的生命周期管理； ——存储、归档、删除、销毁等弱秘密、强秘密和已建立的秘密密钥的机制。 注意 - 通过使用弱秘密生成或检索的密钥不会比弱秘密本身的总和更安全地防止耗尽。 在此条件下，建议在低安全性环境中实际使用 ISO/IEC 11770 本部分中指定的机制。 [外文原描述]： ISO/IEC 11770-4:2006 defines key establishment mechanisms based on weak secrets, i.e., secrets that can be readily memorized by a human, and hence secrets that will be chosen from a relatively small set of possibilities. It specifies cryptographic techniques specifically designed to establish one or more secret keys based on a weak secret derived from a memorized password, while preventing off-line brute-force attacks associated with the weak secret. More specifically, these mechanisms are designed to achieve one of the following three goals. Balanced password-authenticated key agreement: Establish one or more shared secret keys between two entities that share a common weak secret. In a balanced password-authenticated key agreement mechanism, the shared secret keys are the result of a data exchange between the two entities, the shared secret keys are established if and only if the two entities have used the same weak secret, and neither of the two entities can predetermine the values of the shared secret keys.Augmented password-authenticated key agreement: Establish one or more shared secret keys between two entities A and B, where A has a weak secret and B has verification data derived from a one-way function of A's weak secret. In an augmented password-authenticated key agreement mechanism, the shared secret keys are the result of a data exchange between the two entities, the shared secret keys are established if and only if the two entities have used the weak secret and the corresponding verification data, and neither of the two entities can predetermine the values of the shared secret keys. Password-authenticated key retrieval: Establish one or more secret keys for an entity, A, associated with another entity, B, where A has a weak secret and B has a strong secret associated with A's weak secret. In an authenticated key retrieval mechanism, the secret keys, retrievable by A (not necessarily derivable by B), are the result of a data exchange between the two entities, and the secret keys are established if and only if the two entities have used the weak secret and the associated strong secret. However, although B's strong secret is associated with A's weak secret, the strong secret does not (in itself) contain sufficient information to permit either the weak secret or the secret keys established in the mechanism to be determined.