Keys

Locks

There are many different kinds of locks. Most of the locks that you'll play with on a day-to-day basis are pin tumbler locks, primarily of two brand names:

• Schlage (slightly sturdier, more versatile)
• Kwikset (slightly less sturdy, made of sand)

The inside of a typical pin tumbler lock, animation shows how the pins are set to enable the cylinder to turn and release the latch/deadbolt:

<img src="http://toool.us/deviant/01-operation/1.06-key_operation_(side_view).gif" width="300px">

Educational Resources

• Cylinder Locks on Wikipedia
• Lockpicking slides and links by TOOOL (The Open Organisation of Lockpickers)

Law

• In California, it is lawful to duplicate existent keys. Further, a "Locksmith" is defined as a person who engages "in the business of rekeying..." etc, "for any consideration or compensation whatsoever" ('consideration' meaning benefit of a contract i.e. not a gift).
  • Locksmith Act (index) of the Business and Professions Code.
  • SECTION 6980 of the Business and Professions Code:

(j) "Locksmith" means any person who, for any consideration or
compensation whatsoever, engages, directly or indirectly and as a
primary or secondary object, in the business of rekeying, installing,
repairing, opening, modifying locks, or who originates keys for
locks, including, but not limited to, electronic cloning of
transponder keys and any other electronic programming of automotive
keys and electronic operating devices, such as key fobs, door and
ignition key devices, and successive electronic and other
high-security key technology. A "locksmith" does not mean a person
whose activities are limited to making a duplicate key from an
existing key.

• In California, it is lawful to possess lock picks (i.e. circumvention tools) by statue, the state must prove criminal intent.
  • Section 466-469 of the California Penal Code

California Penal Code - §s 466-469. Burglarious And Larcenous Instruments And Deadly Weapons. 
§ 466. Every person having upon him or her in his or her possession a picklock, crow, keybit, crowbar, screwdriver, vise grip pliers, water-pump pliers, slide hammer, slim jim, tension bar, lock pick gun, tubular lock pick, floor-safe door puller, master key, ceramic or porcelain spark plug chips or pieces, or other instrument or tool with intent feloniously to break or enter into any building, railroad car, aircraft, or vessel, trailer coach, or vehicle …, , or who shall knowingly make or alter, or shall attempt to make or alter, any key or other instrument named above so that the same will fit or open the lock of a building, railroad car, aircraft, vessel, trailer coach, or vehicle …, without being requested to do so by some person having the right to open the same, or who shall make, alter, or repair any instrument or thing, knowing or having reason to believe that it is intended to be used in committing a misdemeanor or felony, is guilty of a misdemeanor. 
§ 466.3. (a) Whoever possesses a key, tool, instrument, explosive, or device, or a drawing, print, or mold of a key, tool, instrument, explosive, or device, designed to open, break into, tamper with, or damage a coin-operated machine …, with intent to commit a theft from such machine, is punishable by imprisonment … or by fine ….