Hi JOwen,
couple of my submissions as #8 & #9.I put a keyhole inside "O" to represent the security.I designed that just according to your requirements, as you can see that logo can be used for white background as well as with colored OR dark backgrounds...Colors are exactly as you asked like royal blue, silver & black..Fonts are very professional & popular too..I hope you like these entries..Kindly let me know if you need any changes.Thanks!
Regards,
Immo0~