Storing  valuables,  such  as  money,  jewels, precious metals, or narcotics, in the same container with classified material risks the security of that material. Someone could open or steal the container, resulting in the compromise of the information contained in it. For identification purposes in the event of emergency  destruction  or  evacuation,  place  a number or symbol indicating its priority on the exterior  of  each  security  container:  However, conceal the level of classification of the material stored inside the container. Store Top Secret material in a safe-type steel filing container having a built-in, three-position, dial-type  combination  lock  approved  by  the General Services Administration. Alarm systems or guards who are U.S. citizens protect storage containers, vaults, or vault-type rooms located in areas or structures controlled by another country. The physical barrier of an alarmed area used for the storage of Top Secret material prevents the following: (1) secret removal of the material and (2) observation that would result in the compromise of the material. The physical barrier is such that a forcible attack will leave evidence of an attempted entry into the room or area. The alarm system immediately notifies the U.S. security force of an attempted entry. COMBINATION LOCKS AND KEYS. —The development of the manipulation-proof (MP) and the manipulation-resistive (MR) locks in 1950 advanced security awareness to the point that secure locking devices now exist. A security filing cabinet, vault, or strong room is now fitted with a lock that resists opening of the container by unauthorized persons. This lock is a vast improvement over the antiquated methods of safeguarding before the MP and MR locks were developed. The MP and MR locks have more advanced features  designed  to  protect  against  expert manipulation than those found in conventional locks. These locks have at least 100 graduations on the dial, which provide a choice of at least 1 million  combinations.  A  three-tumbler  lock prevents them from being unlocked when more than one full dial graduation occurs on either side of the proper number for each tumbler wheel. Federal specifications governing the manu- facture of security filing cabinets and security vault doors require that units be equipped with a top-reading changeable combination lock. The top-reading  design  replaced  the  front-reading design to provide increased protection against someone  getting  the  combination  by  secretly watching it being used. To help ensure the effectiveness of combina- tion locks, comply with the following security requirements: 1. 2. 3. 4. 5. 6. 7. 8. 9. Allow only those persons who are cleared for the highest level of classified material stored in the container to change combina- tions. Give the combination only to those persons whose official duties demand access to the cent airier. Change combinations when placed in use, at least annually thereafter, and when any of the following occurs: a. An individual knowing the combination no longer requires access. b. The combination has been compromised or the security container has been discovered unlocked and unattended. c. The container (with built-in lock) or the padlock is taken out of service. (When that happens, reset built-in combination locks  to  the  standard  combination 50-25-50.) Reset combination padlocks to the standard combination 10-20-30. In selecting combination numbers, do not use multiples of 5; simple ascending or descending arithmetical series; and per- sonal data, such as birth dates and social security numbers. Do not use the same combination for more than one container in any one area. In setting a combination, use numbers that are widely separated by dividing the dial into three parts and using a number from each third as one of the combination numbers. To prevent a lockout, have two different people try a new combination before closing the container or vault door. Assign a security classification to the combination equal to the highest category of classified materials authorized to be stored in the vault or container. Seal  records  of  combinations  in  the envelope provided wit h Standard Form 700 (fig. 9-10), Give the envelope to the security manager,  duty  officer,  communication officer, or any other person designated by the command to keep the records on file. When key-operated, high-security padlocks are used, control the keys at the highest level of classification of the material being protected. 9-22