The Security Function

We lost a OnePlus3T dev phone at work earlier this month. This upset me a lot, but later when I reached home and performed my customary routine of locking my cycle to the side railing, I questioned myself if I really have to go through the pain of locking the bicycle every single day - it's added effort and maybe even for no use. Much of security feels that way - 99% of the times nothing will happen, but the day it does you'll curse yourself for not being more careful. I tried coming up with a model to justify whether the daily time spent on securing these valuables was worth it. Here's a simple mathematical equation.

 (Securing Justified) = 

 Price (precious_object) 

 - Price (things_bought_to_keep_it_safe) 

 - [ Value (daily_time_spent_to_keep_it_safe) x (#_of_days_from_purchase_till_theft) ] 

If >> 0, yes, you should definitely go through the pain of securing your valuable everyday.

If ~ 0, you could probably do without securing it. The amount of time you spend securing it over time is worth the object itself.

If < 0, you over-insured, you should definitely stop.

Price (things bought to keep it safe) -> this could be a lockable drawer, a lock and key, maybe even the initial charge of finding a security guard to protect the valuable.

Value (daily time spent to perform security operation) -> convert the amount of time you spend on locking into a more measurable form like money. If you charge $30 per hour of work, locking might be worth a minute's value a day = $0.50. This could also be the running expense of daily wage of the security guard.

# of days from purchase till theft -> This is tricky to calculate. Based on the probability of the object being stolen, and how long you will be using the object for, make an estimate of when the object will be stolen. To simplify things, you could assume the valuable is equally like to be stolen on any day, and if you were to use the object for T years, it'd be stolen somewhere in the middle, say T/2 years. This is a terrible assumption, but I have no clue how else it could be calculated.

So! Finally, to verify if this equation works, take the my bicycle I lock every night.

Price(Bicycle) = Rs 21,000

Price(Things bought to keep it safe) = Rs 1,000

Value(daily time spent to keep it safe) = 2 minutes (to lock and unlock) = Rs 1 [Indians work at $30 a day]

# days from purchase till theft = I'll be using this bicycle for 3 years, so let's say it gets stolen after 1.5 years.

∴ Security Justified = 21,000 - 1,000 - 1 * 548 = 19,452.

Definitely worth securing this everyday.

As for the OnePlus3T, 

Price(OnePlus3T) = Rs 30,000

Price(Things bought to keep it safe) = Rs 1,000

Value(daily time spent to keep it safe) = Rs 500 [Security guard paid that much per day]

# days from purchase till theft = We assumed we'll use the phone for 2-3 years, but we lost it 3 months from purchase.

∴ Security Justified = 30,000 - 1,000 - 500 * 90 = -16,000.

So, having the security guard was totally useless. 

However, I'm starting to think my equation is flawed - the guard isn't looking after just this, but about 100 other objects on the floor. Let me know if you come up with a better model!

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* We saw the CCTV footage concluded it must have been nicked by the security guard himself! No one else entered the floor during the time we last saw it. There is no way to confirm this however, as the camera was placed at the entry of the floor. Apparently, you're not allowed to record footage of employees working.