Windows 7 home premium 64bit w/ SP1 applied.
Updates failing are security updates kb3212646,2871997,2984972,3003743,3011780,3060716, 3071756,3126587, and MSRT kb890830
SFC scan found no problems, but I've attached the CBS log anyhow.
The error insists the Cryptographic Service has issues, but services.msc shows that it and all of its dependencies are automatic and started.
chkdsk found no problems.
memcheck found no problems.
I've run the Update Readiness Tool.
I've run MicrosoftFixit50362
I've tried disabling windows firewall.
There is no security software installed except Security Essentials (if that qualifies )

I've completely reset and reinstalled windows update agent with the following script:
net stop bits net stop wuauserv net stop appidsvc net stop cryptsvc Del "%ALLUSERSPROFILE%\Application Data\Microsoft\Network\Downloader\qmgr*.dat" Ren %systemroot%\SoftwareDistribution SoftwareDistribution.bak Ren %systemroot%\system32\catroot2 catroot2.bak sc.exe sdset bits D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU) sc.exe sdset wuauserv D:(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)(A;;CCLCSWLOCRRC;;;AU)(A;;CCLCSWRPWPDTLOCRRC;;;PU) cd /d %windir%\system32 regsvr32.exe atl.dll regsvr32.exe urlmon.dll regsvr32.exe mshtml.dll regsvr32.exe shdocvw.dll regsvr32.exe browseui.dll regsvr32.exe jscript.dll regsvr32.exe vbscript.dll regsvr32.exe scrrun.dll regsvr32.exe msxml.dll regsvr32.exe msxml3.dll regsvr32.exe msxml6.dll regsvr32.exe actxprxy.dll regsvr32.exe softpub.dll regsvr32.exe wintrust.dll regsvr32.exe dssenh.dll regsvr32.exe rsaenh.dll regsvr32.exe gpkcsp.dll regsvr32.exe sccbase.dll regsvr32.exe slbcsp.dll regsvr32.exe cryptdlg.dll regsvr32.exe oleaut32.dll regsvr32.exe ole32.dll regsvr32.exe shell32.dll regsvr32.exe initpki.dll regsvr32.exe wuapi.dll regsvr32.exe wuaueng.dll regsvr32.exe wuaueng1.dll regsvr32.exe wucltui.dll regsvr32.exe wups.dll regsvr32.exe wups2.dll regsvr32.exe wuweb.dll regsvr32.exe qmgr.dll regsvr32.exe qmgrprxy.dll regsvr32.exe wucltux.dll regsvr32.exe muweb.dll regsvr32.exe wuwebv.dll netsh winsock reset netsh winhttp reset proxy net start bits net start wuauserv net start appidsvc net start cryptsvc echo INSTALL THIS NOW: echo THEN REBOOT pause
I've seen a few other users post about this error and get a custom-made zip package, such as here: Windows Update Error code 800B0100 - Unknown Error

How is that package generated? I'd like to know for the future.