AR 380-19 Information Systems Security

Chapter 4
Communications Security

4-1. Overview

In addition to those policies that apply to all subdisciplines of ISS, there are certain policies that deal exclusively with communications security. These policies establish requirements to deny unauthorized persons access to classified or unclassified-sensitive information while it is being electrically transmitted from the sender to the receiver. They also establish requirements to prevent the derivation of valuable information from other aspects of communications (such as traffic flow and message analysis), and to enhance the authenticity of communications.

a. Communications security techniques will be applied to the extent necessary to deny information to the enemy and provide an effective defense against interception, traffic analysis, and imitative deception.

b. Telecommunications system security objectives will be an integral part of program planning for all telecommunications systems, including those integral to weapons systems and weapons support systems, and will be addressed throughout the system's life cycle. Systems planning shall include, at a minimum, threat analysis and vulnerability assessments to support operational requirements, to establish resource allocation priorities, and to establish and satisfy requirements for countermeasures. If the system includes telecommunications and AIS, the planning process will be integrated to include both the telecommunications and the AIS security aspects.

c. Only approved cryptosystems will be used within the Army. Approved cryptosystems include-

(1) Government-developed and produced systems (machine, automanual, or manual).

(2) Government-developed cryptographic equipment produced commercially under the NSA authorized vendor program.

(3) Commercially developed and produced cryptoequipment using an algorithm approved by NSA under the Commercial COMSEC Endorsement Program.

(4) Commercially developed and produced cryptoequipment using the Data Encryption Standard (DES).

d. Commercially developed equipment using the DES or other commercially developed algorithm will not be used to protect classified information.

e. Systems will be designed and deployed using embedded cryptography to the maximum extent possible. When embedded cryptography is not employed, off-line machine, automanual, or manual systems will be used to provide the required security, if the transmission is not otherwise protected.

f. COMSEC requirements for Army systems will emphasize small, reliable, lightweight, low-powered equipment that is unclassified when unkeyed. COMSEC will be achieved with no increase in the frequency band width required by the equipment it supports. Requirements must also address interoperability, both for routine and contingency operations.

g. Only keying material produced by NSA, or generated by NSA-approved key generators, will be used for keying cryptosystems which protect classified or unclassified-sensitive information.

h. Maximum use will be made of remote electronic keying and rekeying of cryptographic systems that have that capability.

i. Classified and unclassified-sensitive communications between Army activities and contractors will be protected according to this regulation. Procedures for contractors to procure the necessary equipment will be published by HQDA (SAIS-ADS).

j. Authentication will be used to defend against imitative communications deception and establish authenticity of stations, transmissions, and communicators. Authentication may be inherent to the communications equipment.

k. Safeguarding and control of COMSEC material, including controlled cryptographic items (CCI), is governed by AR 380-40 and TB 380-40-22.

l. The Army Communications-Electronics Operation Instructions Program will be implemented per AR 105-64.

4-2. Protection of classified Information

a. Classified information will be transmitted only by secure means. When information transits an area not under access controls as stringent as required for that classification of the information, it will be secured by encryption or a protected distribution system. Fiber optic lines can also be adequately protected by Intrusion Detection Optical Communications Systems approved by NSA and listed in their Information Systems Security Products and Services Catalogue.

b. Only NSA-endorsed COMSEC products will be used to encrypt classified information.

4-3. Protection of unclassified-sensitive information

a. Protection of unclassified-sensitive information during transmission will be consistent with the risk of disclosure, loss, misuse, alteration, destruction, or nonavailability.

b. US1 information described in paragraph 1-5c(1) will be protected in transmission by an NSA-approved technique (see e below) unless a waiver is granted under procedures established by HQDA (SAIS-ADS).

c. US2 information described in paragraph 1-5c(2)(a) also requires protection in transmission unless waived by an official authorized to accredit AIS processing unclassified-sensitive data as specified in 3-8a(7) or 3-8b(5). If the transmission of this data is included in the accreditation of an AIS, the waiver will be documented and approved as part of the AIS accreditation. If protection is not waived, techniques approved by NSA (see e below) or the National Institute of Standards and Technology (NIST) will be used to protect the data.

d. US2 information described in paragraph 1-5c(2)(b) does not require protection to ensure confidentiality, nor is a waiver to protection requirements required. However, protection measures may be used to ensure data integrity or availability. Techniques approved by NSA (see e below), NIST, or other techniques (such as redundancy checks or message acknowledgments) may be appropriate.

e. NSA-approved techniques that may be used separately, or in various combinations, to protect the transmission of unclassified-sensitive information are-

(1) Encryption. There are a number of cryptographic products and associated keying materials acceptable for this purpose. These products are listed in NSA's Information Systems Security Products and Services Catalogue.
(a) Type I products. Type I products may be used to protect both classified and unclassified information.

(b) Type II products. Type II products may be used only to protect unclassified information, and are handled as an Endorsed for Unclassified Cryptographic Item (EUCI).

(c) DES equipment. Unclassified cryptographic equipment employing the DES algorithm that NSA has endorsed as meeting the requirements of Federal Standard 1027 may be used only to protect the transmission of unclassified information.

(2) Unencrypted cable circuits. Although encryption is the preferred protection, unencrypted cable circuits of copper or fiber optics may be used. The degree of protection provided will depend on the type of cable used. The least vulnerable to exploitation is fiber optic cable, followed by copper coaxial cable, and copper strand cable. Cable protection can be enhanced by burying the cable underground or in walls or floors, and providing access controls for entry to cable vaults, rooms, and switching centers. Unencrypted cable circuits can be employed to transmit unclassified information under the following two conditions:
(a) They are used only within the geographic boundaries of the United States or within areas totally within its control overseas.

(b) Adequate measures are implemented so that circuits are maintained on cable and not converted to unencrypted radio transmission.

(3) Protected services. Commercial telecommunications companies offer certain services that are endorsed to protect the transmission of unclassified information. The companies authorized to offer such services are listed in NSA's Information Systems Security Products and Services Catalogue.

4-4. Radio systems

a. All voice or data military radio systems used for transmitting classified or unclassified-sensitive information will be secured or securable by an approved cryptosystem. Military radios are those built or adopted for use as standard military communications systems with a type classification or military nomenclature.

b. In the absence of embedded or machine cryptosystems for existing radio systems, automanual or manual cryptosystems will be used to provide the needed security. However, all future procurements must comply with 4-4a of this regulation.

c. Excluded from the requirements of 4-4a and 4-4b are-

(1) Radios that only relay encrypted information.

(2) Commercial systems purchased or obtained to fulfill an administrative function.

(3) Radios used for public safety communications with civil agencies or to communicate on civil aviation channels. This exclusion does not apply to communications dealing with aviation combat operations.

4-5. Protected distribution systems

a. Communications circuits can be protected by appropriate physical, acoustical, electrical, or electromagnetic safeguards so that classified data can be transmitted on these lines in clear text. These circuits must be formally approved as a protected distribution system (PDS).

b. A PDS will be used only if it is cost-effective and is sufficiently controlled to prevent covert penetration and interception.

c. AIS that include a PDS to transmit data will not be accredited to operate until the PDS has been approved. The PDS approval will be cited in the COMSEC portion of the accreditation packet, and a copy of the approval will be attached.

d. A PDS must be constructed according to criteria published by HQDA (SAIS-ADS).

4-6. Approval of protected distribution systems

a. Authority to approve a PDS for the clear text transmission of classified information within fixed plant and garrison installations is delegated only as follows:
(1) Principal HQDA officials for activities under their staff supervision, direction, or control.

(2) MACOM commanders, or their designees at MACOM level, for their organic activities.

b. Requests for approval of a PDS to transmit top secret information must include an evaluation by the INSCOM support element. Approval authorities may request technical assistance from the INSCOM support element in applying security criteria and processing the approval action for other PDS.

c. Commanders of battalion and higher echelons may approve circuits for clear text electrical transmission of secret and confidential information in tactical environments. Under combat conditions, commanders may delegate this authority to the company level. Tactical PDS will not be approved for clear text transmission of top secret information.

d. Once a PDS is approved, no changes in installation, additions, or use may be made until approval for such changes has been granted by the approval authority.

e. Requests to approve a PDS will be submitted through channels to the appropriate approval authority. Requests will be classified "confidential" as a minimum and will contain the following information:

(1) Full identification and location of the requesting organization.

(2) A statement of the classification of information to be transmitted on the PDS.

(3) A copy of the building floor plan (or a diagram of the field area as appropriate) designating the following:

(a) Proposed cable route and location of subscriber sets, distribution frames, junction boxes, and any other components associated with the circuit.

(b) Other wiring along the PDS route.

(4) Description of the cable installation (for example, 24 pairs of shielded cable in rigid steel conduit, 6 pairs of shielded cable in floor, or fiber optic cable), and the cable length.

(5) Description and nomenclature of terminal and subscriber equipment to be used.

(6) Clearance of individuals having access to the circuit.

(7) Type of guards (for example, U.S. Military, U.S. civilian, foreign civilian), and their security clearance or access authorization status.

(8) Description of access control and surveillance of uncleared personnel who may be allowed entry into the area housing any part of the PDS.

(9) Identification of the power source to be used for the PDS, and a statement of the distance to the nearest point where undetected tampering would be possible.

(10) A statement that teletypewriter circuits will or will not use low-level keying and signaling. This statement is not applicable to fiber optic circuits.

(11) A justification for using the proposed PDS.

(12) A statement concerning any deviations from the established PDS criteria, and an evaluation of their security implications.

(13) For PDS used with top secret information, a copy of the INSCOM evaluation.