Abstract: In open environment, digital certificate is used in identity authentication and authorisation rrmnagement. Digital certificate often includes sensitive attributes, so the research on preserving confidentiality of sensitive attributes in digital certificate becomes concerned. This paper presented a flexible and practical scheme to preserve confidentiality of sensitive attributes in digital certificate, and analysed its security and performance. In the scheme, the different sensitive attributes in digital certificate are encrypted with different sub-keys generated from a main key. The scheme has some characteristics as follows; selectively disclosing sensitive attributes in digital certificate, simple key management, and low time cost. Based on X. 509,the presented scheme was implemented.

Key words: Digital certificate, Sensitive attribute, Preserve confidentiality, X. 509