Source : Free On-Line Dictionary of Computing

SYSKEY
     
         A utility that
        {encrpyts} the {hashed} {password} information in a {SAM}
        database using a 128-bit {encryption key}.
     
        SYSKEY was an optional feature added in {Windows NT} 4.0 SP3.
        It was meant to protect against {offline} password {cracking}
        attacks so that the SAM database would still be secure even if
        someone had a copy of it.  However, in December 1999, a
        security team from {BindView (http://www.bindview.com/)} found
        a security hole in SYSKEY which indicates that a certain form
        of {cryptoanalytic} attack is possible offline.  A
        {brute-force attack} then appeared to be possible.
     
        Microsoft later collaborated with BindView to issue a fix
        (dubbed the 'Syskey Bug') which appears to have been settled
        and SYSKEY pronounced secure enough to resist brute-force
        attack.
     
        According to Todd Sabin of the BindView team RAZOR, the
        pre-RC3 versions of {Windows 2000} were also affected.
     
        {BindView Security Advisory
        (http://packetstorm.securify.com/9912-exploits/bindview.syskey.txt)}.
     
        {BindView press release
        (http://www.bindview.com/news/99/1222.html)}.
     
        {Microsoft bulletin
        (http://www.microsoft.com/Security/Bulletins/ms99-056.asp)}.
     
        (2000-07-16)