Overview of Locksmithing <ul><li>Splash! 2007 (November 18) </li></ul><ul><li>Sho Uemura (meeg@mit.edu) </li></ul>
What is locksmithing? <ul><li>The science and art of making and defeating locks </li></ul><ul><li>Lockpicking uses knowled...
Why study locks? <ul><li>Not because it’s useful (it’s not) </li></ul><ul><li>Know the law  and  be ethical </li></ul>
Lock design <ul><li>The purpose of a lock is to make something more accessible to the owner than to attacker </li></ul><ul...
<ul><li>Lock must be cheap and durable </li></ul><ul><li>Lock must be easy and fast to open </li></ul><ul><li>Key/combinat...
Lockpicking <ul><li>Every technique relies on one weakness of the design: the dominant imperfection </li></ul><ul><li>Two ...
Pin tumbler lock <ul><li>Most common type of key lock today </li></ul><ul><li>Cheap, mass-produceable, durable, compact </...
<ul><li>Key has cuts of varying depths </li></ul><ul><li>Lock has spring-loaded pins that contact the key </li></ul><ul><l...
The sequencing defect <ul><li>Locks are designed to test key/combination at multiple points simultaneously </li></ul><ul><...
Picking a pin tumbler lock Ideal lock: all pins are same size, and holes are in a straight line; all pins must be set at t...
How to crack a lock <ul><li>Bypass the lock </li></ul><ul><li>Use “magic” </li></ul><ul><li>Decoding </li></ul>
Opening locks with magic: bumpkeying <ul><li>Hit the bottom of a pair of pins, and the top pin bounces up; a gap is create...
Bypassing a lock <ul><li>Push the bolt back: shimming (for padlocks), carding and sliding (for doors) </li></ul><ul><li>Re...
Shortcuts <ul><li>Drill holes in a lock to see combination or break pins </li></ul><ul><li>“ Read” previously dialed combi...
Common design improvements <ul><li>Sidebars </li></ul><ul><li>Security pins </li></ul><ul><li>Pin-in-pin locks </li></ul><...
<ul><li>Same principle as pin tumbler, but pins lie in a circle </li></ul><ul><li>Advantage: lock must be picked 6-8 times...
Impressioning a tubular lock
Multiple-dial combination lock <ul><li>Combination is a string of dial positions </li></ul><ul><li>Bolt has teeth touching...
Multiple-dial combination lock <ul><li>Sequencing: Since the bolt contacts some wheels before others, each wheel’s gate ca...
Single-dial combination lock <ul><li>Cheap, simple; very popular </li></ul><ul><li>Can be very secure; used in most safes ...
Single-dial combination lock <ul><li>Combination is series of dial rotations </li></ul><ul><li>Dial pushes wheels inside l...
Lock manipulation <ul><li>Uses the sequencing defect </li></ul><ul><li>Ideally, all wheels contact the fence </li></ul><ul...
Warded lock <ul><li>Oldest type of lock (Ancient Rome) </li></ul><ul><li>Easy and cheap to make </li></ul><ul><li>Insecure...
<ul><li>Key has notches of varying shapes in varying places </li></ul><ul><li>Lock has wards blocking the key’s path </li>...
Lever tumbler lock <ul><li>Evolved from warded lock </li></ul><ul><li>Chubb detector lock is still one of the best locks e...
<ul><li>Key has bittings of varying heights </li></ul><ul><li>Lock has levers with cuts in varying positions </li></ul><ul...
Further reading <ul><li>MIT Guide to Lockpicking </li></ul><ul><li>Wikipedia </li></ul><ul><li>OldLocks.com </li></ul><ul>...
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Locksmithing

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  • Locksmithing

    1. 1. Overview of Locksmithing <ul><li>Splash! 2007 (November 18) </li></ul><ul><li>Sho Uemura (meeg@mit.edu) </li></ul>
    2. 2. What is locksmithing? <ul><li>The science and art of making and defeating locks </li></ul><ul><li>Lockpicking uses knowledge of lock design </li></ul><ul><li>Lock design uses knowledge of lockpicking </li></ul>
    3. 3. Why study locks? <ul><li>Not because it’s useful (it’s not) </li></ul><ul><li>Know the law and be ethical </li></ul>
    4. 4. Lock design <ul><li>The purpose of a lock is to make something more accessible to the owner than to attacker </li></ul><ul><li>Convenience: minimize difficulties for owner </li></ul><ul><li>Security: maximize difficulties for attacker </li></ul>
    5. 5. <ul><li>Lock must be cheap and durable </li></ul><ul><li>Lock must be easy and fast to open </li></ul><ul><li>Key/combination must be easy to carry </li></ul><ul><li>Design should be expandable </li></ul><ul><li>Picking the lock must take time, training and tools (the three T’s) </li></ul><ul><li>Method of entry should not be reliable and repeatable (the two R’s) </li></ul>Principles of design
    6. 6. Lockpicking <ul><li>Every technique relies on one weakness of the design: the dominant imperfection </li></ul><ul><li>Two methods: “mind” and “hand” </li></ul><ul><li>“ Mind”: fool the lock into thinking you have the key </li></ul><ul><li>“ Hand”: use weaknesses in design to bypass lock security </li></ul>
    7. 7. Pin tumbler lock <ul><li>Most common type of key lock today </li></ul><ul><li>Cheap, mass-produceable, durable, compact </li></ul><ul><li>Many variations, but basic principle is the same </li></ul>
    8. 8. <ul><li>Key has cuts of varying depths </li></ul><ul><li>Lock has spring-loaded pins that contact the key </li></ul><ul><li>If all pins are at the correct heights, cylinder turns </li></ul>Pin tumbler internals
    9. 9. The sequencing defect <ul><li>Locks are designed to test key/combination at multiple points simultaneously </li></ul><ul><li>Imperfect manufacture -> some points are tested before others </li></ul><ul><li>Guess each point in sequence to pick a lock </li></ul><ul><li>100000 combinations, but only 50 guesses </li></ul>
    10. 10. Picking a pin tumbler lock Ideal lock: all pins are same size, and holes are in a straight line; all pins must be set at the same time to open lock Reality: some pins will bind in their holes before others; this creates a sequence in which the pins can be picked
    11. 11. How to crack a lock <ul><li>Bypass the lock </li></ul><ul><li>Use “magic” </li></ul><ul><li>Decoding </li></ul>
    12. 12. Opening locks with magic: bumpkeying <ul><li>Hit the bottom of a pair of pins, and the top pin bounces up; a gap is created </li></ul><ul><li>Hit all the pins at once, and the gaps allow the cylinder to turn! </li></ul>
    13. 13. Bypassing a lock <ul><li>Push the bolt back: shimming (for padlocks), carding and sliding (for doors) </li></ul><ul><li>Remove the lock </li></ul><ul><li>Open door from inside </li></ul>
    14. 14. Shortcuts <ul><li>Drill holes in a lock to see combination or break pins </li></ul><ul><li>“ Read” previously dialed combination </li></ul><ul><li>Research lock type - limited combinations, preset combinations, key cut depths </li></ul><ul><li>Skeleton keys </li></ul>
    15. 15. Common design improvements <ul><li>Sidebars </li></ul><ul><li>Security pins </li></ul><ul><li>Pin-in-pin locks </li></ul><ul><li>Tubular pin tumbler lock </li></ul>
    16. 16. <ul><li>Same principle as pin tumbler, but pins lie in a circle </li></ul><ul><li>Advantage: lock must be picked 6-8 times to unlock </li></ul><ul><li>Disadvantage: pins are more exposed </li></ul><ul><li>Flaw: Impressioning </li></ul>Tubular lock
    17. 17. Impressioning a tubular lock
    18. 18. Multiple-dial combination lock <ul><li>Combination is a string of dial positions </li></ul><ul><li>Bolt has teeth touching dials </li></ul><ul><li>Correct combination aligns gates in dials with the bolt </li></ul>
    19. 19. Multiple-dial combination lock <ul><li>Sequencing: Since the bolt contacts some wheels before others, each wheel’s gate can be found to open the lock </li></ul><ul><li>Decoding: A thin piece of plastic can feel the gates in the wheels directly </li></ul>
    20. 20. Single-dial combination lock <ul><li>Cheap, simple; very popular </li></ul><ul><li>Can be very secure; used in most safes </li></ul>
    21. 21. Single-dial combination lock <ul><li>Combination is series of dial rotations </li></ul><ul><li>Dial pushes wheels inside lock </li></ul><ul><li>Correct combination aligns each wheel with fence </li></ul>
    22. 22. Lock manipulation <ul><li>Uses the sequencing defect </li></ul><ul><li>Ideally, all wheels contact the fence </li></ul><ul><li>If one wheel sticks out, the fence will drop down at that wheel’s gate; this identifies that wheel’s combination </li></ul><ul><li>Repeat for all wheels to get combination </li></ul>
    23. 23. Warded lock <ul><li>Oldest type of lock (Ancient Rome) </li></ul><ul><li>Easy and cheap to make </li></ul><ul><li>Insecure </li></ul>
    24. 24. <ul><li>Key has notches of varying shapes in varying places </li></ul><ul><li>Lock has wards blocking the key’s path </li></ul><ul><li>If notches correspond to wards, key can rotate through to push a bolt </li></ul>Inside a warded lock
    25. 25. Lever tumbler lock <ul><li>Evolved from warded lock </li></ul><ul><li>Chubb detector lock is still one of the best locks ever designed </li></ul><ul><li>Complex, bulky, fragile and expensive </li></ul>
    26. 26. <ul><li>Key has bittings of varying heights </li></ul><ul><li>Lock has levers with cuts in varying positions </li></ul><ul><li>Bolt is released when all levers are raised to the correct position </li></ul>Lever tumbler lock
    27. 27. Further reading <ul><li>MIT Guide to Lockpicking </li></ul><ul><li>Wikipedia </li></ul><ul><li>OldLocks.com </li></ul><ul><li>“ Locks, Safes and Security” by Marc Weber Tobias </li></ul><ul><li>Crypto.com - Matt Blaze </li></ul>

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