在计算机安全中，授权凭证（英语：Authorization certificate，缩写为 AC），又称属性凭证（attribute certificate）是一种数字文档，其中的内容，包括了由发行者签署，赋与凭证所有者的属性数据。当相关属性数据都是与授权有关时，这类文档就称为授权凭证。这类文档由X.509进行标准化。RFC 5755则特别规范了在互联网上使用的授权凭证标准。

授权凭证以公开密钥认证的机制运作。

In computer security, an attribute certificate, or authorization certificate (AC) is a digital document containing attributes associated to the holder by the issuer. When the associated attributes are mainly used for authorization purpose, AC is called authorization certificate. AC is standardized in X.509. RFC 5755 further specifies the usage for authorization purpose in the Internet.