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Department of Defense Security Institute






February 1997


Secure transmissions — whether telephone conversations, facsimile (fax) copies, or automated information systems (AIS) communications — have long been possible through encryption, but for many years the equipment was bulky, complex, and expensive. In the 1960s the KY-3, one of the first practical voice encryption devices, came on the market. In 1970, the Secure Telephone Unit, First Generation (STU-I) was launched, followed in 1975 by the STU-II, which mustered some 10,000 users.

In 1984, the National Security Agency (NSA) initiated the Future Secure Voice System (FSVS), an aggressive, accelerated program to button up US voice communications by the end of the 1980s. In fact, the Secure Telephone Unit, Third Generation (STU-III) was developed and produced by 1987. To ensure widespread use, the STU-III was designed to be about the size of a conventional telephone desk set, user-friendly, and relatively low-cost.

In 1986, National Communication Security Instruction (NACSI) 6002, "Protection of Government Contractor Telecommunications," was issued requiring defense contractors to transmit classified information and sensitive unclassified information solely over encryption equipment approved by the NSA. In 1987, the NSA-approved STU-III placed secure telephone service within the reach of nearly every defense contractor.

AT&T, GE (formerly RCA), and Motorola are the vendors for the STU-III. The Type 1 terminal is used to secure classified information and unclassified but sensitive information. All STU-IIIs are compatible, so if you obtain a STU-III from, say, GE it can "go secure" with a STU-III made by Motorola or AT&T. The Type 2 terminal is used to secure unclassified communications only.

We developed this handbook to assist Facility Security Officers (FSOs) of cleared defense contractors who require the STU-III, Type 1 unit. It covers step-by-step what you need to know and do to make the STU-III a valuable addition to your facility's operations. It summarizes and synthesizes directive guidance for the STU-III to supplement, not replace, such guidance. This guidance does not apply to the Type 2 terminal.


First, determine which contracts will require STU-III, Type 1 access. As a rule of thumb, you should count all of your classified contracts in the total. Secure telecommunication via STU-III will improve your facility's performance on virtually any classified contract.

Work with your facility's top management to ensure that the contracting officer for each classified contract inserts a statement of the requirement for protecting the telecommunication of classified information (and unclassified national security-related information).

You will also need to know the highest classification level involved for each contract, so that telecommunications can be safeguarded at that level. Then determine how many STU-III terminal users there will be for each contract.


Now is not too early to consider where you will put the STU-III equipment. In choosing locations, remember that in a cleared facility STU-III terminals must be installed only in private offices or work areas where access to the STU-III may be controlled in keeping with the requirements to protect Controlled Cryptographic Item (CCI) equipment. A CCI, such as the STU-III, must be safeguarded as a high-value item, that is, as though it were a computer.

Will STU-III equipment be used in applications besides in-facility telephone terminals? You may need to use a STU-III for secure facsimile (fax) or AIS transmission. Perhaps there is a need for a cellular unit installed in a vehicle. Someone may need to use a STU-III at a residence. Take all of these uses into account from the outset.

Once you have drawn up a list of the STU-III applications at your facility, you can decide how many STU-IIIs you will require by type (e.g., single-line or five-line desk unit; cellular unit; mobile/ portable/ transportable unit).

KSD-64As, KEY, and CIKs

Next you need to decide how many KSD-64As you will need. Each STU-III comes with one blank KSD-64A.

KSD-64A stands for Key Storage Device with storage of 64,000 bits of information. The device is a key-shaped piece of plastic that contains a computer chip called an EEPROM. The EEPROM chip has Electronically Erasable Programmable Read Only Memory. The device is inserted like a key into a slot in the STU-III and turned to engage its computer chip with the electronic components of the STU-III. Since the KSD-64A is an EEPROM, NSA can use its special equipment to program it, erase the information it contains, and reprogram it with other information.

Key Storage Device, KSD-64A

It is incidental, even confusing perhaps, that the KSD-64A is key-shaped. It is in fact named for the cryptographic information, called "key" by security professionals, that it often stores. "Key" is a unique sequence of random bits used to set up and change the encoding and decoding function of a security device so that it can encode, decode, and authenticate information. It is this meaning of "key" that is used in the following terms:

SEED KEY - Key that is loaded into a STU-III terminal, enabling it to electronically obtain its operational key during a rekey phone call.

OPERATIONAL KEY - Key that is loaded into a STU-III terminal, enabling it to make direct secure calls to other STU-IIIs.

The KSD-64A may also function as a CIK:

CIK - A KSD-64A that stores an electronic "password." The CIK is inserted and turned in the STU-III terminal that shares this "password" to unlock the terminal's secure transmission features. The secure mode is locked when the CIK is removed. CIK stands for Crypto Ignition Key.

A particular KSD-64A is commonly referred to by the type of electronic information it is storing at the time. A KSD-64A that is used to transport and transfer seed key to a STU-III unit is called a "seed key." A KSD-64A that is used to transport and transfer operational key to a STU-III unit is called an "operational key." A KSD-64A that contains an electronic "password" is called a "CIK."

Note also that when a KSD-64A is used to transport and transfer either seed key or operational key, it is referred to as a fill device. It will "fill" the unkeyed STU-III with key; when, in addition, a CIK has been created and is inserted in the unit, the STU-III is said to be keyed.

The Electronic Key Management System, Central Facility (EKMS) generates and distributes all key used by STU-IIIs. The EKMS prepares customized key by combining user-specified ID information and NSA-generated cryptographic information. After the EKMS has generated the customized key, it assigns to it a unique Key Material Identification Number (KMID). The customized key, referred to as the terminal's key, is then loaded into a fill device. A card label attached to the fill device identifies the key contained in the device. The fill device is then shipped to a COMSEC account (COMSEC = Communications Security), where it is officially received and provided to an individual authorized to key the STU-III terminal (i.e., to load the key into the terminal).

A fill device may be used just once to transfer key; after the transfer the fill device is empty or blank. A KSD-64A or a STU-III that does not contain key is said to be zeroized; a button at the rear of the unit (Motorola and RCA/GE) or on the bottom of the unit (AT&T) is used to zeroize the STU-III. A fill device is required to key the STU-III only during initial setup and later on to rekey the STU-III after it has been zeroized (for instance, to change its ID information).

A STU-III into which operational key has been transferred (loaded) is ready to operate in the secure mode. However, a STU-III unit into which seed key only has been loaded must have its seed key converted to operational key before it can go secure. The STU-III user initiates this conversion by placing a call to the EKMS. During this call, the EKMS electronically converts the seed key in the STU-III to operational key.

During this call, the EKMS also downloads the latest Compromise Information Message/Compromised Key List (CIM/CKL) into the STU-III. When NSA determines that a possible compromise has occurred, it places the number of the compromised key (its KMID) onto the CKL. Updates to this list are provided in a CIM, which is exchanged automatically between the STU-III terminals during the setup, or handshake, for a secure call. If the KMID of a STU-III terminal is on the CKL, no other STU-III terminal can establish secure communications with it.

Since operational key enables a user to make a secure call without having to be converted, it is more vulnerable to compromise than seed key. For this reason, NSA prefers not to transmit to STU-III users fill devices containing operational key. We will include operational key in what follows, but unless there are special circumstances at your facility, only "seed keys" should be ordered.


Determine how many keysets of each STU-III unit will be needed. A keyset consists of a combination of "key" and user ID data. The number of keysets that are available within a STU-III differs by vendor, as shown:

Only one keyset is needed per STU-III, unless some users have a different clearance level and/or need-to-know than other users of that STU-III. If more than one keyset is needed, a separate seed key (or operational key) with its own identifying information must be obtained for each keyset you establish within the STU-III. For each keyset, the STU-III terminal can create a master CIK, which will permit you to enable and disable some security functions of the STU-III and to create additional CIKs in the future as needed. With all of the STU-III models, up to 7 CIKs can be created per keyset if a master CIK is also made; otherwise, up to 8 CIKs per keyset can be created. The CIKs that enable a given keyset (designated for secure use at a particular classification level and with a particular need-to-know) within the STU-III will not enable any other keyset.

Once you know the number of keysets you will be using, you also know the minimum number of seed keys [and/or operational keys] that will be required. Bear in mind, however, that you may wish to order duplicate fill devices from the EKMS, so that they will be on hand to refill the STU-III if you have to zeroize it (or if an employee zeroizes it by accident).

You will also need to decide whether to create one or more master CIKs. That is, for each keyset to be established, you must determine whether:

1. No master CIK need be created,

2. A master CIK will be created only to enable/disable some security functions of the STU-III, then zeroized, or

3. A master CIK will be created and retained to create additional CIKs in the future as needed. In this case, the facility must have storage capability at the level of the seed key's conversion classification level or a higher level.

Next, determine how many regular CIKs will be needed. Will you issue a CIK to each STU-III user? Or will you have only one or a few CIKs for each keyset, available for common use?

Once you know your needs __ keysets per terminal, CIKs per keyset, fill devices (seed key/operational key) per keyset, and the number of terminals by type __ you are ready to obtain your STU-III equipment.


Next, you need to settle on the method of obtaining the STU-III, Type 1 equipment. The contractor (your company) and the contracting officer negotiate agreements that govern how the costs of the STU-III capability will be treated under existing or new contracts that require the securing of telecommunication of classified information or unclassified but sensitive Government information.

There are three main methods of obtaining a STU-III terminal, as follows:

GFEA US department or agency, normally the User Agency for the contract, purchases the STU-III equipment and provides it to the contractor as Government Furnished Equipment (GFE). The government provides disposition of the equipment at the conclusion of the contract. The STU-III equipment may also be obtained as GFE under the NSA/DIS Loan Program, under which the Defense Investigative Service has loaned out approximately 5,700 STU-IIIs to NSA-approved contractors. Under this program, a contractor may retain the STU-III as long as a classified contract is maintained. Then the government handles disposition.

CAPUpon authorization of the contracting officer, the contractor may purchase the equipment from a vendor and charge it to the contract as Contractor Acquired Property (CAP). CAP is owned by the government, which handles disposition at the end of the contract.

COPSubject to an administrative determination by NSA that the contractor is eligible from a security viewpoint to own the equipment, the contractor may obtain it from a vendor as plant equipment as defined in the Federal Acquisition Regulation, 48.101(a). The equipment becomes Contractor Owned Property (COP). The contractor may recover the cost as for other plant equipment overhead. Only companies organized and existing under the laws of the US and Puerto Rico may acquire the STU-III as COP. (See COMSEC Supplement to ISM, Section V, para. 32b.)

Once a STU-III has been obtained as GFE, CAP, or COP, it may be redistributed to a subordinate entity, such as a division or subsidiary:

HRThe STU-III is provided on a hand receipt (HR) by a home office, parent company, or some other entity which will execute the STU-III COMSEC requirements.

If the contractor is to acquire the STU-III equipment directly, i.e., under CAP or COP, send a letter to the NSA Central Office of Record (NSA COR) at this address:

National Security Agency

Operations Building Nr. 3

ATTN: Y131

9800 Savage Road

Fort George G. Meade, MD 20755-6000

If CAP, provide in the letter:

A request for eligibility to directly procure the STU-III equipment.

If COP, provide in the letter:

NSA will determine the contractor's eligibility to procure the STU-III equipment and will notify the contractor in writing. The contractor will be required to execute a CCI Control Agreement with NSA.

How you obtain your STU-III determines whether your facility will need to execute a CCI Control Agreement and have a COMSEC account.

Under the NSA/DIS Loan Program, a Memorandum of Loan Agreement is required.

Required only when the facility has to obtain its own key.

If your organization is obtaining the STU-III equipment under CAP or COP, it must execute a CCI Control Agreement with NSA. If you do not have a blank CCI Control Agreement, obtain one from:

If your organization is obtaining the STU-III equipment as GFE under the NSA/DIS Loan Program, it must execute a Memorandum of Loan Agreement. If a COMSEC account is in place at your facility, or if an existing COMSEC account is available to support the requirement, well and good. If not, you will need to initiate a request for the establishment of a COMSEC account with NSA.


A COMSEC account is "an administrative entity identified by an account number, responsible for maintaining custody and control of COMSEC material." Simply put, NSA or some other governmental agency will establish an accountability system for your COMSEC equipment (STU-III) and other necessary material (key) and will assign a 6-digit number to the account.

As the chart above shows, a COMSEC account is required unless your facility is receiving both the STU-III and the key under a hand receipt issued by another entity, such as a home office. In this case your facility is using the COMSEC account of the other entity, which is assuming the accounting responsibilities. If, however, the STU-III comes to your facility on a hand receipt and if you are instructed to obtain the key on your own, then you must establish a COMSEC account with NSA.

If your contract or the instructions you have received indicate that the STU-III and key are the only COMSEC material needed, you will be applying for a STU-III Only COMSEC Account (SOCA) . If you have been told that you will need additional COMSEC equipment, such as a KG-84 or KG-94, then you must obtain a regular COMSEC account.

In applying for the COMSEC account, you need to nominate to NSA the persons who will serve as COMSEC Custodian and Alternate COMSEC Custodian. If the key is at, or will convert to, the SECRET level or below, they must have final SECRET clearances. If the key is at, or will convert to, the TOP SECRET level, they must have final TOP SECRET clearances. When applying for a regular COMSEC account, the investigative basis for each clearance (investigation or periodic reinvestigation) must fall within the past 5 years.

To apply for the COMSEC account send a letter to the NSA COR at the following address:

National Security Agency

Operations Building Nr. 3

ATTN: Y131

9800 Savage Road

Fort George G. Meade, MD 20755-6000

Include in the letter:

Send a copy of the letter to your DIS Field Office.

If your method of obtaining the STU-III equipment is CAP or COP, attach a copy of the CCI Control Agreement executed by your organization to the letter sent to the NSA COR.

When the NSA COR has reviewed your documentation, they will respond to you by letter, with a copy to the DIS Field Office. The letter will confirm the establishment of the COMSEC Account, the assignment of the 6-digit account number, and the appointment of the COMSEC Custodian and Alternate. The letter will include a copy of the CCI Control Agreement you forwarded, now also executed by NSA.


The COMSEC Custodians are responsible for the accounting, handling, and disposition of all key for your STU-III terminals. They must verify that the persons to whom they issue key have an appropriate security clearance and need-to-know and that STU-III users follow your Standard Practice Procedures. Requirements and procedures for COMSEC Custodians are detailed in Section III, para. 18, of the COMSEC Supplement to the ISM and in Section 8 of the STU-III Key Management Plan.

If you (the FSO), the COMSEC Custodian, and the Alternate COMSEC Custodian have not received a COMSEC briefing by a government representative, arrange for your DIS IS Representative to give the briefing. Also, if the COMSEC account will receive COMSEC material besides STU-III material, you must arrange for the COMSEC Custodian and the Alternate to attend the NSA CS-140 COMSEC Custodian Course. However, even if your account is a SOCA, we recommend that the COMSEC custodians take this course.

Once your COMSEC account is in place, the NSA COR will send a copy of National Security Telecommunications and Information Systems Security Instruction (NSTISSI) 3013, "Operational Security Doctrine for the Secure Telephone Unit III (STU-III) Type 1 Terminal" and its annexes. However, if other INFOSEC policy documents are needed for contract performance, the contractor must request the User Agency contracting officer to provide the documents as Government Furnished Property (GFP).

For further guidance, have the COMSEC Custodian obtain the following:

From DIS:

From NSA:

From EKMS:


Next, nominate to the EKMS a person to serve as the Command Authority. The three responsibilities of the Command Authority are:

1. To establish Department/ Agency/ Organization (DAO) descriptions, which will become part of the customized key issued by the EKMS and part of the identification displayed in the message window of the distant STU-III during a secure call.

2. To select and register the User Representative, indicating appropriate "privileges," which include:

3. To monitor and maintain the accuracy of the User Repre-
sentative information on file at the EKMS.

Send the Command Authority appointment letter to:

EKMS Central Facility

P.O. Box 718

Finksburg, MD 21048-0718

The appointment letter must:

After the EKMS has processed your letter, it will send letters confirming the appointment of the Command Authority to both the contractor and the Command Authority, as a double check to detect any data entry errors or attempts to make unauthorized appointments.


Besides the confirmation letter, the EKMS will send the Command Authority a package of information that includes the "User Representative Registration Form." The Command Authority can then appoint and register the User Representative. (See Section 6 of the STU-III Key Management Plan.) Note that in a small organization one person may serve as COMSEC Custodian, Command Authority, and User Representative. The User Representative's responsibilities are:

1. To determine requirements for key within the organization,

2. To interact with the Command Authority for DAO administration and User Representative privilege changes,

3. To prepare and submit key orders to the EKMS, and

4. To monitor the status of key orders.

Responsibilities and procedures for the User Representative are detailed in Section 7 of the STU-III Key Management Plan.

After the EKMS has processed the registration form, they assign the User Representative a 6-digit identification number to use when ordering key. As with the double-check confirmation of the Command Authority appointment, the EKMS will send letters confirming the registration of the User Representative to both the Command Authority and the User Representative to detect any data entry errors or attempts to make an unauthorized registration.

When the registration of the User Representative is confirmed, ensure that an approved contractor employee __ such as you (the FSO), the COMSEC Custodian, or the Alternate __ gives a COMSEC briefing to the User Representative.

Next, ensure that the Command Authority and the User Representative check the information (registration data and ordering privileges) entered on the "STU-III User Representative Key Ordering Authorization Form" sent to them by the EKMS. The User Representative keeps this form for use when ordering key.


Recall that each STU-III terminal stores certain user-specific identification information and displays this information during a secure call. The display is critical because each party uses it to authenticate the distant party. For this reason, the identification information is also referred to as "authentication data." There are two parts to the identification: the DAO description and the Additional Identification Data ("free form" information).

The Command Authority defines the DAO description, which specifies the terminal user's parent department, agency, or organization. The DAO description may be one or two lines:

 The first line of a contractor's DAO description is the name of the US Corporation or other legal entity for which the Command Authority is appointed (e.g., Electric Widget Corporation). This line is displayed on the terminal of the distant party throughout a secure call.

A second line can be used to show location, division, or staff element (e.g., Electric Widget Services). It is displayed briefly to the distant user during the secure call setup.

The Command Authority supplies the DAO description as part of registering the User Representative. The EKMS then assigns a unique 6-digit number (the DAO code) to the DAO description. The User Representative uses the DAO code when placing an order for key.

To order the required seed key(s) [and/or operational key(s)], the User Representative must do the following:

The User Representative next enters the second part of the user identification: the Additional Identification Data, or "free form" information. The STU-III user determines this information, such as a specific location, section, position (title), or project, even the user's name, and notifies the User Representative. In all, three lines are available for authentication data. If the Command Authority has already specified a two-line DAO description, then there can be only one line of free form information:



LASER WIDGET Additional Identification Data

If the Command Authority specifies only a one-line DAO description, there can be up to two

lines of free form information:


LASER WIDGET Additional Identification Data

CHIEF ENGINEER Additional Identification Data


If additional KSD-64As will be needed, now is a good time to order them from one of the two vendors: Datakey and CTS Corporation. (See inside back cover for further information.)


If you are obtaining your STU-III as GFE __ for instance, under the NSA/DIS Loan Program __ or under a hand receipt, the equipment and vendor are selected for you. If, however, your method of obtaining the STU-III is either COP or CAP, then your facility will normally be allowed to select the vendor.

You should acquire brochures from AT&T, GE, and Motorola and talk with their representatives. Talk also with contractors who have STU-IIIs. You'll find some obvious differences, such as price, and others that are more subtle.

When you have decided on which STU-III unit to purchase, contact the vendor. Certify your facility's eligibility to the vendor and provide the following:

Then issue the purchase order, and the vendor will send the STU-III to your facility.


Next, decide on the security procedures for the facility's STU-IIIs, fill devices, master CIK(s), and CIKs and prepare the STU-III Standard Practice Procedures (SPP). Tailor the SPP to your specific operation. Remember that although the user will be briefed on the use of the STU-III and the security precautions for the unit, the user's primary source of information will be the SPP.

DIS has several STU-III SPPs to assist you. The next time your IS Representative comes by, discuss what you need — or make a call. To get you started, the contents might include:

1. Purpose and Introduction

2. Definitions

3. Security Education

4. Roles and Responsibilities

5. Clearances and Need-To-Know

6. Physical Storage

7. Access Controls

8. Safeguards During Use

9. Secure Data Transmission (Fax & AIS)

10. Accountability

11. COMSEC Incidents

    1. Emergency Procedures

13. Attachments

COMSEC briefing

User Briefing or STU-III SPP Certification

STU-III Terminal / KSD Hand Receipts

STU-III Secure Call Log

Fax Log

The SPP must address the following ISM requirements, as applicable:

STU-III with fax:


STU-III outside cleared facility:

STU-III in vehicle:


The COMSEC Custodian will take receipt of the seed key(s). Although seed key is UNCLASSIFIED CRYPTO, it can be received only by a COMSEC Custodian who is cleared to the level of the operational key to which the seed key will be converted. The COMSEC Custodian should:

If there is any difficulty, call the EKMS immediately at 1-800-635-5689. Note the discrepancy on the SF 153, and send it to the EKMS/CAO.

Ensure that each seed key, which is UNCLASSIFIED CRYPTO, is left in its unopened plastic bag until use and is safeguarded by the best means available at your facility (e.g., GSA-approved security container) until it is loaded.


The COMSEC custodian takes receipt of any operational key as above for seed key, except:


Take delivery of the additional KSD-64As, if any, that you ordered from a vendor. No special protection requirements apply to these blank devices, which will become CIKs. Once they become CIKs, however, they are locally accountable items.


You or your designee may take receipt of the STU-III terminal(s).

Remember, each STU-III is a Controlled Cryptographic Item (CCI) (= accountable COMSEC). Note also that the NSA COR one-up transaction numbering system reverts to "1" every January 1. The numbering system applies to all reports (transfer, destruction, possession inventory) that do not list STU-III key. STU-III key must be reported separately; see Receipt of Seed Key, above.

Ensure that each unkeyed STU-III is safeguarded as a high-value item (i.e., as though it were a computer).


The STU-III is easy to assemble and install. Just follow the directions the vendor provides. Attach the handset cord to the handset and main unit. Then insert the telephone cord into an RJ-11 jack (household telephone jack). Finally, supply the power (plug the unit into a 110V wall outlet). That's all there is to it.

You can now use the STU-III in its nonsecure mode just as you would any other telephone. With the STU-III assembled, you may enter phone numbers in its automatic dialer.

If the STU-III will be used for fax or AIS, insert the cable plug from the device into the RS 232 port at the rear of STU-III. The STU-III comes equipped with an internal modem. STU-III data port guidance was recently issued by the National Security Telecommunications and Information Systems Security Committee (NSTISSC) as Annex H to NSTISSI 3013. This annex provides guidance as to what security measures are needed when using the STU-III's data port. Specific data port and computer security requirements are provided by DIS. Copies of Annex H have been disseminated to all NSA-controlled contractor COMSEC accounts. You may also obtain an NSA STU-III fax report by calling (301) 766-8729.


To test the nonsecure operation of each unit, place a nonsecure call. While in the nonsecure mode, the STU-III operates as a Plain Old Telephone System (POTS).


After terminating the nonsecure call, load seed key(s) into the appropriate STU-III(s). Review the STU-III vendor's manual carefully before you start the keying sequence. Once you start the keying sequence you will have from three to ten minutes to complete the sequence and make your first CIK. The amount of time available varies with each make of STU-III. The STU-III is programmed to shut down if the time is exceeded. If this occurs, you will lose your seed key. You would then be required to zeroize the STU-III and insert a new seed key. Remember, there is ample time to complete the keying process. Do not rush.

For each keyset to be established within the STU-III terminal:


After checking the nonsecure operation of the unit(s) to be filled, load operational key(s), if any, into the appropriate STU-III(s). For each keyset to be established within the STU-III terminal, follow the same procedures provided for loading seed key. Once the STU-III is loaded with operational key and a CIK is inserted and turned in it, the STU-III can operate in the secure mode immediately. While it is not necessary to call the EKMS rekey number (1-800-635-6301), you are urged to do so. Calling the rekey number will allow the EKMS to 1) send a new operational key to the STU-III, and 2) send the latest Compromise Information Message/Compromised Key List (CIM/CKL) to the STU-III.


Have the COMSEC Custodian establish local accountability for the CIKs created (see paragraph 8.5.1, STU-III Key Management Plan) and maintain accountability records for them. The local accountability records may be either the fill device card label (yellow CRYPTO ID card) supplied with the key, or another type of record that provides the same information (see Issuing CIKs to Users, below). When using the yellow card, ensure that both sides are completed. Local CIK account-ability records must be retained until the terminal(s) is zeroized.

For each seed key [and/or operational key] loaded, have the COMSEC Custodian complete the final disposition portion of its L6061 card (e.g., date, conversion or zeroization) and file it alphanumerically in the inactive section of the COMSEC Register File. When zeroization is performed, also enter the EKMS STU-III key transaction number.


Destruction reports will seldom be required. However, the COMSEC Custodian must submit an SF 153, completed as a destruction report, to the EKMS in each of these cases:


Protect each keyed STU-III (unit that contains key and that has a CIK inserted in it) at the highest security level of the information that the operational key can protect.


To test the secure operation of each unit, place a secure call.

If the message window:

If the display is not working, terminate the call immediately.


Ensure that any master CIK(s) created only to enable/disable some security functions of the STU-III are deleted from the terminal immediately after such use. Ensure also that any master CIK(s) retained are stored at the converted classification level of the seed key (= the highest classification level that the operational key can protect). If this level is TOP SECRET, then you must have TOP SECRET storage capability. You do not, however, need to impose two-person integrity (TPI) on a TOP SECRET master CIK.


Ensure that each regular CIK is protected as required.


You (the FSO), the COMSEC Custodian, or the Alternate Custodian gives the terminal users a user briefing, to include their reading the STU-III SPP and certifying in writing that they have read and understood the SPP. The briefing must cover at least the following:


Substantial amounts of classified and sensitive unclassified information have leaked to our adversaries over nonsecure telecommunications circuits. Correct use of the STU-III can reduce this vulnerability. All STU-III users must follow sound, consistent security practices in order to prevent the compromise of classified material and communications by hostile intelligence services and other unauthorized persons. The following procedures are provided as general operational guidelines to ensure the proper use of the STU-III:



I have read and fully understand the security measures for the Secure Telephone Unit, Third Generation Type 1, or STU-III, set forth in the STU-III Standard Practice Procedures.

I accept the responsibility of being entrusted with a CIK (Crypto Ignition Key). I am aware that when the CIK is inserted into a STU-III unit, the STU-III/CIK unit becomes classified to the level of the key and must be protected at that level.

I will immediately report the loss of a CIK or a STU-III to the COMSEC Custodian or Alternate COMSEC Custodian.








NOTE: Copies of this certification will be maintained by the Facility Security Officer in the individual's personnel security folder and by the COMSEC Custodian in a separate COMSEC folder.


If provided for in the STU-III SPP, have the COMSEC Custodian issue CIKs to the terminal users and have them each sign either the reverse of the CIK's yellow Crypto ID card or a "CIK Hand Receipt."




CIK Hand Receipt

I, ___________________________________________________, an employee

(Printed Full Name)

of _______________________________________________________, acknowledge


receipt of one CIK (Crypto Ignition Key) having the serial number ________________
and associated with the STU-III terminal having the serial number ________________

I have read and fully understand the STU-III Standard Practices Procedures regarding my responsibilities and agree to abide by them.





NOTE: Copies of this certification will be maintained by the Facility Security Officer in the individual’s personnel security folder and by the COMSEC Custodian in a separate COMSEC folder.


Ensure that the COMSEC Custodian reports to NSA:

Send reports to NSA at this address:

ATTN: X712
9800 Savage Road
Ft. Meade, MD 20755-6000

Send information copies of reports to NSA to the EKMS at this address:

EKMS Central Facility
P.O. Box 718
Finksburg, MD 21048-0718


Establish a continuous program of STU-III security education.


Be sure that each month the COMSEC Custodian compares all seed keys received with all those on hand, those destroyed, and each monthly "Key Conversion Notice" from the EKMS.

In the event that a CIK is lost, have the COMSEC Custodian delete the lost CIK from the appropriate keyset and from its terminal's CIK list. (NOTE: Do not notify the EKMS or NSA COR of the loss of a CIK unless there is an indication of espionage or sabotage.)

Be sure that the COMSEC Custodian conducts the required COMSEC inventory every six months. NSA COR is responsible for all accounting related to the STU-III equipment itself. You will receive an inventory sheet for your STU-III from NSA COR every six months. Report any deficiencies. EKMS/CAO, which is responsible for all accounting related to STU-III key, will likewise send an inventory sheet every 6 months.

Inspect STU-III equipment and usage as part of your facility self-inspection. DIS industrial security representatives will audit contractor SOCAs as part of their regular industrial security inspections. DIS SOCA inspections replace audits by the NSA COR.


Ensure that, for each STU-III, a terminal user performs at least annually an electronic rekey (replacement of operational key with new operational key by means of a telephone call to the EKMS). Although the requirement is to rekey once a year, the EKMS encourages rekeying from two to four times a year. During the rekey call the EKMS will send the STU-III the latest CIM/CKL. The user should note the following:

Ensure that, if needed, the COMSEC Custodian performs a physical rekey of the STU-III (replacement of operational key with new operational key by means of a fill device, KSD-64A). An electronic rekey call to the EKMS should also be made to ensure that the STU-III terminal receives the most recent CIM/CKL.


Zeroize and refill the STU-III as needed. The STU-III battery backup allows power to be removed, as in a power failure or unplugging the unit to move it, without losing the encryption data. The zeroization button bypasses this backup and erases the encryption data. After zeroization, the STU-III must be rekeyed and the CIKs must be remade. The STU-III is zeroized:

In an Emergency. - If the STU-III is ever in danger of falling into hostile hands, zeroize it to prevent the adversary from obtaining a functional unit.

For Transfer or Code Change. - If you need to transfer the STU-III to another entity of your organization or if you wish to change the DAO code (identifier), zeroize the STU-III and refill it using the new seed key [or operational key].

By Accident. - The accident usually follows an employee's curiosity. The employee starts playing with the buttons and zeroizes the unit. Be sure to brief your employees on the importance of not pressing or playing with the zeroization button. Refill the STU-III using a new seed key [or operational key].

For Shipment. - If you are required, for maintenance or other reasons, to return the STU-III to the vendor, DIS, or other government agency, you should normally zeroize it.


Ensure that no STU-III is moved without the prior approval of the COMSEC Custodian.

Ensure too that if the STU-III is ever shipped from the facility, no CIK that enables it is ever shipped with it. The CIK must be packaged and shipped separately.


Ensure that the Command Authority monitors the User Representative(s) and keeps the EKMS informed of any changes in personnel or privileges. The "User Representative Registration Form" also serves as the means of notifying the EKMS of such changes.


Ensure that your company executes a new CCI Control Agreement when necessary:

1.In the event that the name of the company changes. Any change in a company name invalidates a CCI Control Agreement, and

2.In the event that your facility is covered under a corporate CCI Control Agreement and has been "bought out" by another company whose corporate headquarters does not have an agreement on file with NSA.


Have the COMSEC Custodian close the COMSEC account if it is no longer required.


If the contractor's facility clearance is being terminated, a SOCA is in effect, and one or more NSA/DIS STU-III Loan Program terminals are located at the facility, ensure that the following actions are taken:


ACCESS: The ability and opportunity to obtain knowledge of classified or sensitive information, equipment, or other materials; or the ability and opportunity to have unrestricted use, handling, or physical control thereof. The particular requirements for access to different categories of COMSEC materials are detailed in the COMSEC Supplement to the ISM and other official documents.

ACOUSTIC SECURITY: Security practices relating to the prevention of unauthorized overhearing of discussions involving classified or unclassified but sensitive information.

ALTERNATE COMSEC CUSTODIAN: The individual designated by proper authority to perform the duties of the COMSEC Custodian during the temporary absence of the COMSEC Custodian.

AUTOMATED INFORMATION SYSTEM (AIS): An assembly of computer hardware, software, and firmware configured for the purpose of automating the functions of calculating, computing, sequencing, storing, retrieving, displaying, communicating, or otherwise manipulating data, information and textual material.

CENTRAL ACCOUNTING OFFICE (CAO): The part of the Electronic Key Management System (EKMS) that provides accounting support to Central Offices of Record (CORs) and COMSEC Custodians for STU-III key.

CENTRAL OFFICE OF RECORD (COR): A central office which keeps records of all accountable COMSEC material received by or generated within elements subject to its oversight. Usually within a government department or agency, its duties include establishing and closing COMSEC accounts, maintaining records of COMSEC Custodian and Alternate Custodian appointments, performing COMSEC inventories, and responding to queries concerning account management. NSA serves as the COR for most government contractors.

CIK: A key storage device (KSD) that must be plugged into a COMSEC equipment to enable secure communications. It contains an electronic "password" used to lock and unlock a terminal's secure mode. The secure mode is unlocked when the CIK is inserted and turned, locked when it is removed. CIK is the abbreviation for Crypto Ignition Key.

COMMAND AUTHORITY (CA): Individual responsible for managing STU-III key assets for a department, agency, or organization. The Command Authority determines the DAO Description and appoints User Representatives, assigning to them their key ordering privileges.

COMMUNICATIONS SECURITY (COMSEC): COMSEC refers to protective measures taken to deny unauthorized persons information derived from telecommunications of the US Government relating to national security and to ensure the authenticity of such communications. COMSEC protection results from the application of security measures to electrical systems which generate, handle, process, or use national security information and also includes the application of physical security measures to COMSEC information or materials.

COMPROMISE: The disclosure of classified information to persons not authorized access thereto.

COMPROMISED KEY LIST (CKL): A list of compromised STU-III keys distributed by the EKMS to terminals during rekey calls.

COMSEC ACCOUNT: An administrative entity responsible for maintaining custody and control of COMSEC material and identified by a 6-digit account number.

COMSEC CUSTODIAN: The individual designated by proper authority to be responsible for the receipt, transfer, accountability, safeguarding, and destruction of COMSEC material assigned to a COMSEC account.

COMSEC SUPPLEMENT TO THE ISM (CSISM): A section of the Industrial Security Manual published separately as DoD 5220.22-S. It establishes policies, procedures, and responsibilities for the control of COMSEC material furnished to, generated or acquired by US industry. It covers the safeguarding controls for classified and unclassified COMSEC material and equipment resident at cleared industrial facilities.

CONTROLLED CRYPTOGRAPHIC ITEM (CCI) A secure telecommunications or information handling equipment, or associated cryptographic component or ancillary device which is unclassified when unkeyed (or when keyed with UNCLASSIFIED key) but controlled. Equipment and components so designated shall bear the designator "Controlled Cryptographic Item" or "CCI."

CRYPTO: A marking or designator identifying all COMSEC key used to secure or authenticate telecommunications carrying classified or sensitive but unclassified government or government derived information, the loss of which could adversely affect the national interest.

DEPARTMENT/AGENCY/ORGANIZATION (DAO) CODE: A 6-digit identification number assigned by the EKMS to a DAO description and used by the User Representative when ordering key.

DEPARTMENT/AGENCY/ORGANIZATION (DAO) DESCRIPTION: A one or two line designation of the user's parent department, agency, or organization. The Command Authority determines the DAO Description, which forms the first part of the terminal user's identification information (authentication data) and appears in the distant terminal's display during a secure call.

DESTRUCTION REPORT: Documentation on an SF 153 of the physical or electronic destruction of COMSEC material by NSA-authorized means.

ELECTRONIC KEY MANAGEMENT SYSTEM (EKMS): The STU-III system, administered by the EKMS Central Facility, that provides all keying services to the user community.

FILL DEVICE: Any one of a family of devices developed to read in, transfer, or store encryption key (e.g., Key Storage Device, KSD-64A).

GOVERNMENT FURNISHED PROPERTY (GFP): Property in the possession of or directly acquired by the government and subsequently made available to a contractor but of which the Government retains ownership. GFP includes Government Furnished Equipment (GFE).

HAND RECEIPT (HR): A document used to record local or temporary transfer of material from a custodian to a user and acceptance by the user of the responsibility for the material.

KEYED: Containing cryptographic key. In applications employing a CIK, the crypto-equipment is considered keyed when an enabling CIK is inserted in the unit.

KEY STORAGE DEVICE (KSD): The device that can be used as a fill device and also as a CIK for STU-III terminals. It is small, shaped like a key, and contains passive memory (ROM). When it is used to carry key to a terminal it is called a fill device; when it is used to protect encryption key that has been loaded into terminals, it is called a CIK.

KEY MANAGEMENT PLAN: NSA guidance (EKMS-702.01) for managing the accounting and handling procedures for STU-III key.

OPERATIONAL KEY: Encryption key sufficient to enable a STU-III that has been unlocked by an appropriate CIK to make direct secure calls up to a predesignated level of classification with other keyed STU-IIIs.

PERSONNEL (SECURITY) CLEARANCE (PCL): An administrative determination that an individual is eligible, from a security point of view, for access to classified information of the same or lower category as the level of the PCL being granted.

SECURE TELEPHONE UNIT, THIRD GENERATION (STU-III): The STU-III Type 1 terminal is a dual-purpose telephone capable of transmitting voice and data. It may be used as an ordinary telephone that operates over the public telephone network. It may also be used as a secure telephone to communicate through the public telephone network with other STU-III Type 1 terminals (classified and unclassified but sensitive information) and with Type 2 terminals.

SEED KEY: Key that is loaded into a STU-III terminal by a fill device to enable the terminal to electronically obtain its operational key of a predetermined classification during a rekey call to the NSA Electronic Key Management System.

TELECOMMUNICATION: The preparation, transmission, communication or related processing of information by electrical, electromagnetic, electromechanical, or electro-optical means.

UNKEYED: Containing no key or containing a key which has been protected from unauthorized use by removing the CIK.

USER REPRESENTATIVE (UR): An individual or office that operates as the agent of the Command Authority authorized to order key for a particular department, agency, or organization.

ZEROIZE: To remove or eliminate the key from a crypto-equipment or fill device.




National Security Agency (301) 688-8110

Operations Bldg. Nr. 3

ATTN: Y131

9800 Savage Road

Ft. George G. Meade, MD 20755-6000



NSA STU-III Program Office 1-800-328-STU3/7883

ATTN: X24 (410) 684-7073

9800 Savage Road

Ft. George G. Meade, MD 20755-6000



EKMS Central Facility 1-800-635-5689 (Key Assistance)

P.O. Box 718 1-800-635-6301 (Rekey)

Finksburg, MD 21048-0718 (301) 526-3200 (Rekey)



Defense Investigative Service (703) 325-6057

ATTN: V0432

1340 Braddock Place

Alexandria, VA 22314-1651




1-800-243-7883 1-800-521-9689 1-800-922-4357

(919) 279-3411 (609) 727-5282 (602) 437-2822




DATAKEYCTS Corporation

407 West Travelers Trail 9210 Science Center Drive

Burnsville, MN 55337-2554 New Hope, MN 55428-3635

(612) 890-6850

1-800-328-8828 (612) 533-3533

fax (612) 890-2726 fax (612) 553-3037


AIS - Automated Information System

CAO - Central Accounting Office

CAGE - Commercial and Government Entity

CAP - Contractor Acquired Property

CCI - Controlled Cryptographic Item

CIK - Crypto Ignition Key

CIM - Compromise Information Message

CKL - Compromised Key List

COMSEC - Communications Security

COP - Contractor Owned Property

COR - Central Office of Record

DAO - Department/Agency/Organization

DCS - Defense Courier Service

DIS - Defense Investigative Service

DoD - Department of Defense

DoDSI - Department of Defense Security Institute

EKMS - Electronic Key Management System, Central Facility

FAR - Federal Acquisition Regulation

FSO - Facility Security Officer

FSVS - Future Secure Voice System

GFE - Government Furnished Equipment

GFP - Government Furnished Property

HR - Hand Receipt

IS - Industrial Security

ISM - Industrial Security Manual, DoD 5220.22-M

KCN - Key Conversion Notice

KMID - Key Material Identification Number

KSD - Key Storage Device

NACSI - National Communication Security Instruction

NSA - National Security Agency

NSTISSC - National Security Telecommunications and Information Systems Security Committee

NSTISSI - National Security Telecommunications and Information Systems Security Instruction

POTS - Plain Old Telephone System


SPP - Standard Practice Procedures

STU-III - Secure Telephone Unit, Third Generation, Type 1

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Our prices and terms are very competitive, and we offer only the highest quality equipment available in the industry.

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