Isidor Zeuner is a German cryptographer and also a prominent member of the bitcoin developer mailing list. There are not that many people active on the developer mailing list, but he is one of them. You can read some of his stuff here: https://www.mail-archive.com/[email protected]/
We have raised over 5 btc for him to help audit ShadowCash. Info here: http://shadowtalk.org/topic/321/shadowcash-whitepaper-review-and-code-audit
Also as a note, if the audit turns up any flaws or problems with the Shadow system, then its a good thing, and the developers can work to plug holes, and improve the system. Its probably likely that there can be some improvements, but this is hardly a "fail". When Kristov Atlas audited the DRK codebase, he found some flaws in their coinjoin scheme, which they improved upon. This is all part of becoming a hardened coin.