Starting with Windows 8 and Windows Server 2012, Microsoft removed the Elephant Diffuser from the BitLocker scheme for no declared reason. Dan Rosendorf's research shows that removing the Elephant Diffuser had an "undeniably negative impact" on the security of BitLocker encryption against a targeted attack. Microsoft later cited performance concerns, and noncompliance with the Federal Information Processing Standards (FIPS), to justify the diffuser's removal. Starting with Windows 10 version 1511, however, Microsoft added a new FIPS-compliant XTS-AES encryption algorithm to BitLocker.