Starting next month, updated Windows operating systems will reject encryption keys smaller than 1024 bits, which
could cause problems for customer applications accessing Web sites and email platforms that use the keys.
The cryptographic policy change is part of Microsoft's response to security weaknesses that came to light after
Windows Update became an unwitting party to Flame Malware attacks, and affects Windows XP, Windows Server
2003, Windows Server 2003 R2, Windows Vista, Windows
Server 2008, Windows 7, and Windows Server 2008 R2 operating systems, according to the Windows PKI blog