Two separate blog posts to be aware of for anyone interested in cryptography (or Krypto Krap as a former colleague would say).

 

PKI Team blog: Planned August release on Windows Update will block RSA keys weaker than 1024 bits:

http://blogs.technet.com/b/pki/archive/2012/06/12/rsa-keys-under-1024-bits-are-blocked.aspx

 

MSRC blog: detailed technical breakdown on the Flame malware, read the external links at the end for answers to whether MD5 should be used as a signing algorithm today.

http://blogs.technet.com/b/srd/archive/2012/06/06/more-information-about-the-digital-certificates-used-to-sign-the-flame-malware.aspx

 
See also http://blogs.technet.com/b/srd/archive/2012/06/03/microsoft-certification-authority-signing-certificates-added-to-the-untrusted-certificate-store.aspx