Morrowind:Security

The Security skill lets you open locked doors and containers with lockpicks, disarm traps with probes, and re-seal sealed documents after reading them. This skill is essential for agents and thieves alike. Unlocking locked objects is a crime, so make sure you don't let anyone see you do it.

Character Creation

The following races receive bonuses to their Security skill:
+5 bonus: Khajiit
The following classes have Security as a Major skill:
Thief
The following classes have Security as a Minor skill:
Assassin, Bard, Nightblade



Factions
The following factions include Security as one of their favored skills:

East Empire Company
Hands of Almalexia  (not joinable)
House Hlaalu
Thieves Guild
Twin Lamps

Mechanics
Your chance to successfully unlock something is:

 

If the result of that formula is 0%, you will get the message "lock too complex". It will still affect the use count of the tool you attempted to use, though.

While locks come in a wide range of difficulties, from  1 to 100 points, the difficulty level of all traps is the same. As a result, you will never receive a "trap too complex" message when attempting to disarm a trap, although you can still increase the likelihood of a successful disarming by increasing your Agility and Luck attributes, your Security skill and the quality of your Probe.

One other minor use of the Security skill relates to sealed scrolls (of which there are a grand total of 4 in the game).  You are given the option to open and read the scrolls, and after doing so attempt to re-seal them to conceal your tampering.  Your chance of success at this is equal to your Security skill - 1.  In other words, even with maxed Security, you still have a 1 in 100 chance of damaging the seal, which can have negative effects on the related quests.

Alternatives
There are several alternatives to using Security, for those less inclined towards using this skill.
Use the Open spell.  You'll need sufficient skill in Alteration, and a spell strong enough to open the given lock, as well as enough Magicka to cast it.  Still a decent alternative for those more magically gifted.  This will not disarm trapped locks, however.
Find a key.  Not all locks have keys, of course, but quite a few of them do, though often well hidden.  Using a Detect Key spell can save you a bit of searching.  Unlike the Open spell or using a pick, having the key will both open the lock, and disarm the trap if there is one.  However, you will not raise any skills by opening locks with a key.
Use the Telekinesis spell.  This will not help open locks, but it can be a useful way to disarm traps from a safe distance, preventing the trapped containers/doors from hexing your character with their damaging or debilitating spells.  It does require some skill in Mysticism, but Telekinesis is one of the easiest spells to cast, so even those without much magical aptitude can use this technique.
Use an enchanted item.  You may be able to find an Amulet of Opening, which can open some easier locks (up to 20pts).  Or, you can Enchant your own item, either by yourself or by paying someone for the service.  Using an enchanted item will also increase your Enchant skill, a side benefit.
Use a scroll.  Scrolls with Open spells on them are readily available loot in most places, and it's usually not difficult to acquire a good supply of them.  The disadvantage to this is that using scrolls does not raise any skills at all. The best scroll for this is the Scroll of Ekash's Lock Splitter (Open 100 pts. on Target).

Tools
 

Like the Secret Master's alchemy apparatus, the Secret Master's lockpick and probe do not feature anywhere in the game and can only be accessed via the Construction Set.