Ignore the 'keys.zip. It's from a messed up upload. Follow instructions in description.

It seems that the number of dashes (- or _ characters) in the mods have an effect. I'm unable to generate a local key like 'Ares_1_5_0.bikey' or 'Ares-1-5-0.bikey' that avoids the issue. Using 'Ares150.bikey' seems to work tho.

We had a report of something to this effect happening with our rksla3.bikey file as well:

http://forums.bistudio.com/showthread.php?178555-RKSL-Attachments-Pack-1&p=2866462&viewfull=1#post2866462

Can't really work out what's causing it, or why it effects this key on their server (so far they're the only group who have mentioned this problem with our key).

It seems like the '-' theory is busted, I found some more keys that don't work in combination with the newly renamed .bikey file (without the dashes in the name). It has to be something internal to the game since the keys work fine in isolation. For some reason it seems to happen more often with map packs that we try.

I'm not sure if it has something to do with the way the key is generated or something. No matter what, there's an issue in the game where some key combinations hang the server.

BTW the only workaround I have at the moment is to continue to generate different keys until I get one that works with the mod combination that was having an issue, and then re-release with the mod signed with that new key.

From what I can see it's random or at least there is are visible reproduction steps, here is what I was doing past 2 days trying to figure things out.

First, key "CCIP_v0.3a" was conflicting with key "jns_skycranes", removing either of them fixed the issue. Renaming second to "jnsSkycranes" for example fixed the issue, but renaming first to dash or underscore instead of a dot did NOT fix it while renaming it to exclude the dot (03 together) fixed it.

(Arma 3 Tools also doesn't support a dot in the key's name, I've already reported that to the mod's author.)

Second, after I resolved above, I made another random key "missing_units_usec" which conflicted with "jns_skycranes" as well, removing either fixed it yet again. Then renaming first one to "missingUnits_usec" or "missing_units-units" fixed it as well, while renaming it to "missing_units" or "missing_units-usec" or "missing-units_usec" or "missing-units-usec" did NOT fix it.
Renaming second to "jnsSkycranes" or even "jns_sycranes" (without 'k') fixed the issue as well.

'renaming' in all above context means creating a new key, as renaming it plainly doesn't change anything at all. That leads me to a conclusion that the key's name somehow gets corrupted in the actual encryption of the key or whatever it does, so it's not referencing itself correctly or something along the lines.

Similar / Related issue - http://feedback.arma3.com/view.php?id=22567

@LondonLand

It's not the same, but it's related. Since my old bikey "jns_skycranes" bugged out with just one other key (that I could find), but the key was created by previous Arma 3 Tools (stable), the new one with dev-branch and new one "jnsSkycranes" works.

More time showed another interesting thing. With a bunch of mods and keys all worked, removing "randomslap.bikey" broke it again. Yes, *removing* it, this is not making any sense anymore...

Removing ANY other key next to that one made it work again.

I also experience this issue when hosting a non-dedicated server for coop play. Any time I click on 'next' when internet game is selected it will crash arma before mission select screen comes up. Removing mods at random will cause it to eventually work.

There is no way through log files that I know of that would allow me to determine which bikey files cause the issue specifically.

The issue its a bit deeper than keys, sometimes changing loaded addon or even addon load order can result on the server soft-lock the same way.

But its really hard to probide a repo for it because the combinations that cause it seems to be totally random

Looks like they made some changes in Dev Branch 1.46 regarding this. Is this still a problem there?
Re: Fixed: Server issue when using a larger list of BIKEY signature files
Source: http://forums.bistudio.com/showthread.php?149636-Development-Branch-Changelog&p=2939180&viewfull=1#post2939180

this issue should be resolved in Arma 3 DEV 1.45 and Arma RC 3 1.46 and A2: OA 1.63 beta

It looks like it may indeed be fixed
Reference: http://forums.bistudio.com/showthread.php?178224-CBA-Community-Base-Addons-ARMA-3&p=2948723&viewfull=1#post2948723

Thanks

This should probably be resolved as fixed and closed.