modern, simple, clean
maybe a bit web 2.0 but no cute stuff
kestrel possibly but only in a simple, fresh, modern, and stylised way
invoke feelings of being bold and confident, never dull and weak.
connection to what it is representing (i.e., security ) but this shouldn't be cliched (see don't wants)
No more than three colours
Should look good in black and white.
Recognizable when resized
matching "favicon.ico" browser icon would be great
deliverables must include adobe illustrator vector format, .svg, .eps, jpg, .png, and .gif;
LOGOS WE LIKE
No cliches - padlocks, shields, keys, binary ones and zeros etc unless a subtle and very creative interpretation
No garish designs
No intricate details
No globe symbols
Not a distracting logo
No special effects (including, but not limited to: gradients, drop shadows, reflections, and light bursts).
Finally, I don't want to stifle your creativity with too many constraints!