Drafting of messages

Digits

Excerpt of TICOM DF-120:
The numbers (our main source of entry) are not written out anymore but are sent as double letters:
1 is aa, 2 is bb, 3 is cc, … 0 is jj.

Cardinal

        4   = FOUR
        40  = FOUR ZERO (not FORTY)
        400 = FOUR ZERO ZERO (not FOUR HUNDRED)
        455 = FOUR FIVE FIVE

Ordinal

Dates and hours

a. The Army and the Navy use 24-hour clock. In the 24-hour clock, time is always expressed as a group of four numerals. The first two numerals of the group denote the hour and the last two numerals the minute after the hour. Ordinary or 12-hour time may be converted to 24-hour time by adding 12 hours to all times from 1:00 PM to midnight, inclusive.

b. The date may be expressed in either of two ways :
(1) For the current month, the day may be indicated by preceding the four-digit time group with a two-figure date group, indicating the day of the month. For example 080600 ist he 8th day of the month and the time is 6:00 AM.
(2) The date and time may be stated by using the four-digit time group, followed by the month, day, and if desirable the year.

c. The heading of all messges, dispatches, reports, and orders transmitted by radio, telegraph, or cable to the War Department will include the date and the time of origin expressed by six digits as prescribed in b(1) above. The date group, time group, or date-time group may be omitted from messages, dispatches, reports, and orders transmitted by radio in the abbreviated form or abbreviated normal form when necessary.

d. Greenwich Civil Time is used within the Navy and in joint operations, unless otherwise prescribed, and within the Army, in both the heading and text of all communication in the following categories :
(1) Messages and orders from the War Department.
(2) Messages and reports to the War Deparment.
(3) Orders, reports, and other communication between headquarters not having common local time.
(4) Communication with the armed forces of associated nations.

e. All the groups expressing Greenwich Civil Time, including those in the headings of messages, will be desinated by the letter suffix Z immediately following the last digit of the group. For example, 190225Z indicates 2:25 AM on the 19th day of the current month Greewich Civil Time.

Author's example of a time :
10:30PM (2230) will be coded by TWO TWO THREE ZERO HOURS

Important word, individual letter

Joint Army/Navy Phonetic Alphabet (1943) (for example in Signal Corps Technical Information letter No14):

      A: Able     G: George   M: Mike    S: Sail/Sugar  Y: Yoke
      B: Baker    H: How      N: Nan     T: Tare        Z: Zebra
      C: Charlie  I: Item     O: Oboe    U: Uncle
      D: Dog      J: Jig      P: Peter   V: Victor
      E: Easy     K: King     Q: Queen   W: William
      F: Fox      L: Love     R: Roger   X: X-ray

In FM 24-5 (1942) and TM 11-454 (1942), Differences with 1943 version:
A:Afirm, C:Cast, H:Hypo, I:Inter, N:Negat, O:Option, P:Prep, S:Sail, U:Unit, Z:Zed

The phonetic alphabet is also used to list individual letters, for example:

          FM 24-5:  FOX MIKE TWO FOUR DASH FIVE 

Addresses

When addressee and sender addresses correspond directly to the Call Signs, these are sufficient to handling the message. When addresses specify commanding officers, the addressee address is inserted at random within the body and near the beginning of the message preceded by the word "For" (or "To"), and the identity of the writer of the message near the end of the message preceded by the word "From". The position of these insertions varies in order to maintain cryptographic security.

The addresses are enclosed by parenthesis. As the punctuation marks are spelled, a parenthesis is remplaced by the word "PAREN". Now, we can understand the affirmation of the German cryptanalysts that the word "PAREN" can always be found in a depth.

By war's end, PAREN was not the only way to frame an address, americans also used CMA, PD, CLN or XXX (TICOM DF-120).

Exerpt of TM 11-469:
Addresses and signatures within classified messages will be reduced to a minimum. Messages from or to a given command or station automatically are considered as form or to the commander thereof. It is detrimental to security to include within all messages from or within all messages to a particular station the name or title of the commander thereof or any individual in the command.

Never place cryptographed addresses or signatures at the beginning or end of the cryptographed text. Bury them at random in the body of the message.

Abbreviations

In Message Book M-210, there is a partial list of authorized abbreviations. The complete list is contained in FM 21-30 manual. Other manuals contains abbreviations, for example the AR 850-150.

Here an exerpt of these documents.

      Command Post:    CP     Number:    NO     Captain:          CAPT
      Command Officer: CO     Truck:     TRK    Sergeant:         SGT
      General:         GEN    Battalion: BN     Zone of Interior: Z of I
      Colonel:         COL    Company:   CO     Year:             YR
      Lieutenant:      LT     Division:  DIV    December:         DEC
      Tank:            TK     Regiment:  RGT    West:             W
      Headquarters:    HQ     Brigade:   BRIG   Message:          MSG  
      Brigade Adjutant:                  S-1    Infantry:         INF
      Intelligence Officer:              S-2    Ordonance Officer:OO
      Plans and training officer:        S-3    Switchboard:      SB
      Supply Officer:                    S-4    Field Artillery:  FA
      Assistant chief of staff for personnel:                     G-1
      Assistant chief of staff for military intelligence:         G-2
      Assistant chief of staff for plans and training:            G-3
      Assistant chief of staff for SUpply:                        G-4

Avoiding impact of stereotypes

Universal Stereotypes

Types of words:

• Compass directions.
• Correspondence symbols.
• Geographic names associated with the place of origin or destination of message.
• Months.
• Names of persons readily associated with the place of origin destination.
• Numbers.
• Phonetic-alphabet components
• Punctionation (including END, STOP, PD, CMA, QUOTE, UNQUOTE, PAREN, etc.)
• Ranks, grades, titles.

ACKNOWLEDGE	FOR		REPEAT*
ACTION		FROM		REPLY*
ADVISE		HEADQUARTERS	REPORT*
ATTENTION	IN REPLY	REQUEST*
AUTHORITY	INFORMATION	RERAD*
CITE		MAIN		RETEL*
CONDITION	MESSAGE		REURAD*
DATE		OUR		SHIPMENT
DESIRED		PACKAGE		SIGNED
DUTY		PARAPHRASE	STATUS
EFFECTIVE	RADIO		SYSTEM
ENEMY		RECEIPT*	YEAR
FOLLOWING	REFERENCE*	YOUR
* At the beginning only.

• RERAD: Reradiation jamming = Receive-alter-etransmit a signal in order to deceive the enemy.
• RETEL: Referring to telegram.
• REURAD: Refer to (Regarding) your message.

Need for Bisection or Padding

Bisection

The following instructions will be observed by code room personnel when bisection is applied to a message.

a. DIVISION OF MESSAGES. Divide the message into two segments between two words not considered stereotyped or within a word, e below. For example, the following message is divided between the words OF and CODE

       REQUEST FULL INFORMATION CLARIFYING YOUR
       RECOMMENDATION RE REVISION OF  //  CODE
       ROOM PROCEDURE FOR LARGE HEADQUARTERS

b. CONSONANTS. Select at random any consonant except X and Z. Repeat the consonant to make a five-letter group, and place this group at the end of the second segment.

c. TRANSPOSING. Transpose the two segments of the message, placing the second segment first, followed by the five-letter group, and the fist segment last so that the message will be cryptographed in the following order :

	SECOND SEGMENT.
	FIVE-LETTER GROUP.
	FIRST SEGMENT.

	CODE ROOM PROCEDURE FOR LARGE HEADQ-
	UARTERS RRRRR  REQUEST FULL INFORMATION
	CLARIFYING YOUR RECOMMENDATION RE REVI-
	SION OF

Padding

b. PADDING WORDS. Words for padding will be selected according to the following instructions:
(1) Care will be taken to avoid the use of any word which could be interpreted as having any relation to the text of the message. Words indicating the beginning or ending of a message such as start or that is all will not be used.
(2) Words used at the beginning will bear no relation to words used at the end. For example, such beginnings and endings as the following will not be used :
"trolley … car", "Chicago … Illinois."
(3) The type of words used for padding will vary form message to message and within a single message. Names of cities, flowers, fruits, etc. vill not be used habitually.
(4) Care will be taken that the words selected for padding do not themselves become stereotyped. It is suggested that list of randomly chosen of varying lengths be prepared and a check-off method used to prevent repetition of words. A dictionary may be used for this purpose as long as the words are chosen at random.

c. AMOUNT USED. The total amount of padding used will be varied from message to message; within a single message the amount of padding used at the beginning will differ from that used at the end.

d. SEPARATION OF PADDING. Padding will be separated from the beginning and from the ending of the message by the insertion of any doubled consonant except XX and ZZ.

e. REPONSIBLE PERSONNEL. Padding will be added at the point of origin by code room only, and will be removed at the destination by code room personnel prior to delivery of the message to the addressee.

f. EXAMPLES. Examples of the use of padding are as follows:

(1) STIPULATION CEREBELLUM AUTOMOBILE GRAMMATICAL GG CHARLIE FOUR SEVEN DASH THREE ONE VICTOR SEVEN DEP BELEM ONE ZERO ZERO ZERO ZEBRA ETA NATAL ONE TWO ZERO ZERO ZEBRA MM LABOR CIGARETTE CONGRESS

(2) OVERCOAT FF THREE BAKER ONE SEVEN DASH ABLE GEORGE THREE FIVE DASH FOX THREE ONE EIGHT DASH THREE HOW FOX SIX ETA NATAL ZERO EIGHT ZERO ZERO ZEBRA ETA BELEM ONE ZERO ZERO ZEBRA SS MASTADON HAGGARD

Paraphrasing

What?

When?

b. It is necessary to send in cryptographic form:
(1) All or portions of a message previously transmitted in plain text.
(2) Extracts from publications, regulations, or instructions.

c. It is necessary to transmit in plain text all or portions of message previously sent in cryptographic form.

d. A classified message is recryptographed in a different cryptographic system.

e. A classified message is recryptographed in a different key of the same system.

How?

a. Changing the sequence of paragraphs.

b. Changing the sequence of sentences.

c. Shifting the positions of the subject, predicate, and modifiers in each sentence.

d. Changing from active to passive voice.

e. Substituting synonyms or equivalent expressions.

f. Changing the length of the paraphrased version of the message so that the final cipher text will not ressemble the original cipher text with respect to length.

Example

	DESTRUCTION OF BRIDGE AT WETBURG ACCOM-
	PLISHED GERMAN RECONNAISSANCE FORCE CON-
	SISTING OF BATTALION REINFORCED BY PLA-
	TOON OF LIGHT TANKS TRAPPED ON WEST SIDE 

	OF RIVER AND NOW MOVING NORTH BETWEEN
	
        HILLS FOUR THREE TWO AND FIVE ZERO SEVEN
	DASH ABLE UNDER SHELLING FROM OUR ARTIL-
	LERY ENEMY EXPECTED TO ATTEMPT CROSSING
	
        SOUTH OF PILCHEN THEIR SUCCESS PROBABLE
	AGAINST OUT PRESENT STRENGHT UNLESS ADDI-
	TIONAL ARTILLERY AND DIVE BOMBERS AT-
	TACHED PD RECENT TANK DESTROYER REPLACE-
	MENTS ADEQUATE

	NEED MORE CANNON AND DIVE BOMBERS TO PRE-
	VENT ANTICIPATED GERMAN THRUST ACROSS
	RIVER BELOW PILCHEN ADDED TANK DESTROY-
	ERS SUFFICIENT WE HAVE TRAPPED ENEMY RE-
	CONNAISSANCE BATTALION PLUS FEW LIGHT
	TANKS PD BLEW UP WETBURG BRIDGE CATCHING
	THEM ON THE WEST BANK PD AS THEY RETREAT
	NORTH NOW BETWEEN HILLS FOUR THREE TWO
	AND FIVE ZERO SEVEN DASH ABLE OUR GUNS 
	POUNDING THEM

Security tags

Excerpt of TM 11-380 (1947)
c. Separate keys and separate key-list indicators will be provided at all times for CONFIDENTIAL and RESTRICTED traffic except within a division (or smaller tactical unit) preparing its own pin and lug settings. In such units, the same pin and lug setting may be used for CONFIDENTIAL and RESTRICTED traffic and the key-list indicators omitted; all traffic will be considered CONFIDENTIAL unless otherwise specified within the body of the message. If a message is RESTRICTED, the designation XX RESTRICTED XX will be buried in the text before encrypting. When the key-list indicator is omitted, the system indicator will be substituted in its place, and will thus appear twice in the two five-letter indicator groups.
...
i. Converter M-209-(*) will never be used for SECRET traffic except when a system normally authorized for SECRET traffic is not available. When a SECRET message must be enciphered by means of Converter M-209-(*), the CONFIDENTIAL key will be used and the word SECRET, set off by two X’s on each side, will be buried in the text before encrypting.

j. Converter M-209-(*) will not be used for CONFIDENTIAL traffic above the level of corps or comparable organization except as authorized by the Army Security Agency of the theater or the War Department.

k. Separate keys and separate key-list indicators will be provided at all times for CONFIDENTIAL and RESTRICTED traffic except within a division (or smaller tactical unit) preparing its own pin and lug settings. In such units, the same pin and lug setting may be used for CONFIDENTIAL and RESTRICTED traffic and the key-list indicators omitted; all traffic will be considered CONFIDENTIAL unless otherwise specified within the body of the message. If a message is RESTRICTED the designation XX RESTRICTED XX Will be buried in the text before encrypting. When the key-list indicator is omitted, the system indicator will be substituted in its place, and will thus appear twice in the two five-letter indicator groups.

References