The August Revolution was a success!

On 2 August 1945, in Ba Dinh Square, President Ho Chi Minh solemnly read the Declaration of Independence, giving birth to the Democratic Republic of Viet Nam.

The newly established democratic republican government had to cope with a situation of endless complications. In the South, the French army, hiding behind the British military, landed in Saigon-Cholon, continuing their aggressive plots against our nation. In the North, nearly 200,000 of Chiang Kai-Shek's military came, in the name of the Allied Forces, to disarm the fascist Japanese, and escorted gangs of lackies plotting to overthrow the authority organized by the Viet Minh [Viet Nam Independence League]. Reactionary gangs in the nation took advantage of the people's rising to act to counter and destroy the resistance. The Japanese-French imperialist gangs provoked famine and ran wild.

Faced by the devious plots of enemies both foreign and domestic, together with difficulties in every respect in our homeland after the revolution had just succeeded, the fate of our nation at that moment faced a very dangerous situation, for "money and necessities were hanging on a hair."

In order to confront the enemy's aggressive plots against our nation – in order to protect the incipient authority of the people – the Standing Committee of the Central Party and President Ho Chi Minh proposed some urgent tasks to strengthen authority, counter the French colonialists' aggression, abolish crime, raise the standard of living of the people, and especially to show concern for supplying concrete guidance in building revolutionary armed forces.

On 7 September 1945, President Ho Chi Minh entrusted to Cde Hoang Van Thai responsibility for establishing the General Staff organization. (Cde Vo Nguyen Giap was also present at the occasion). When assigning the task, Uncle said: "Our people have just won their independence, their freedom – all of our nation is starting to build an army of resistance and self-defense to safeguard our independence, our freedom. Pursuant to collective instructions, the Staff [Bo tham muu] is established to help Central exercise command of the army in our whole nation.

"As the secret organization of the collective – as the nerve center of the army – the Staff is responsible for military strength, for forging weaponry, for knowing the enemy, in order to defeat every enemy.

"At this time we have no experience – do not yet understand staff work – have many difficulties. But we have to strive to overcome this, studying even as we work. With determination, many difficulties can be worked through. Somehow we must also build a staff branch of our army that is solid and powerful, worthy of the tradition of giving one's mind to forwarding and preserving the nation of the Vietnamese peoples."^[3]

On 8 September 1945, Cde Hoang Van Thai sponsored the first meeting of comrades to introduce the organizations of the General Staff, in order to determine and allocate responsibilities.

On 9 September 1945, the Military Communications-Liaison Bureau of the General Staff was officially established, under Cde Hoang Dao Thuy. From a week before, according to instructions from the Central Party Standing Committee and Uncle Ho, Cde Vo Nguyen Giap, Minister of Internal Affairs in the provisional revolutionary government, and concurrently Commander-in-Chief [

Immediately upon being established, the Communications-Liaison Bureau started to develop the organization of a network [

With the Central Party concerned with assignment of people and getting equipment, a few of the fellows took it upon themselves to search out old radio stations in French depots, and, after just a short time, an official military radio liaison net was inaugurated, comprising the High Command and General Staff in Hanoi with the combat sectors of Dong Trieu, Viet Bac, [Northern Viet Nam, or Tonkin], and Hoa [Binh]-Ninh [Binh]-Thanh [Hoa]; the Revolutionary Military Affairs committee of Trung Bo [Central Viet Nam, or Annam]; and the Military Affairs Committees of Thua Thien-Hue and Da Nang. Besides the military liaison network, liaison between the Central radio offices (Hanoi) and those of Trung Bo and Nam Bo [Southern Viet Nam, or Cochin-China] was maintained and shaped, making a liaison network of military postal and radio [service] throughout the nation.

In the first days of the revolutionary regime, the leadership and command comrades, the organizations sending messages and those receiving messages, and the communications organizations equally felt uncomfortable sending messages over the military radio or via the post offices in plain text, unenciphered. Thus an urgent requirement was to research methods of using cryptography so as to ensure communication security.

Cde Hoang Van Thai personally reviewed and approved the plan to establish the Cryptographic Section [

On 12 September 1945, the Military Cryptographic Section, the first cryptographic organization of the army, was established, tasked with research, production, and use of cryptographic systems to ensure the secrecy of leadership and command communication of the various echelons of the army going via the various means of communication (principally by radio). This was also the first cryptographic organization of our nation.

The twelfth of September has since been taken as the birthday of the army cryptographic branch.

At the beginning, the Cryptographic Section lay in the Bureau of Communication-Liaison. The working area was a room behind that of Cde Bureau Chief Hoang Dao Thuy in building No. 16 Riquer Street,^[4] adjacent to the General Std organizations.

In accordance with a proposal by Cde Hoang Dao Thuy, Cde Vo Nguyen Giap appointed Cde Ta Quang De,^[5] who was working in the Ministry of Internal Affairs, to transfer to the General Staff and assume charge of the cryptographic mission.

Having received the responsibility and concrete recommendations of Cde Hoang Van Thai, and after determining the particulars and mission components, Cde Ta Quang De circumspectly proceeded to select people who could be introduced to the work of cryptography. The "criterion" for selection was based on estimation of a "good, trustworthy person," and an additional condition was "ready-to-go," no family ties, committed to an assignment requiring total reliability. A number of the fellows who were introduced by responsible people to cryptographic work prior to the organization were intellectuals and petty officials, and at the same time Boy Scouts from [troops] such as Dinh Loan, Thuyen, Hoang Quy Quan;^[6] also young Miss Bui Thi Loan, a liberation army soldier returned from the combat sector. After a few days, Nguyen Tu Khang, Bach Tuong, Sam, Dich, then Tran Mi Thach in turn were introduced to the work.

After working together a few weeks, the fellows did some brainstorming about many aspects of this new assignment. Prior to this time, the colonialist French gang had not ever instructed Vietnamese people, or entrusted them, in our own cryptographic organizations, so there was no one who thoroughly understood the business. Therefore, the ideas shared by these fellows, together with revolutionary enthusiasm, built up trust on the part of the leadership comrades. Afterwards, in a situation in which people to perform cryptography were lacking in various places and in accordance with arrangements by Cde Hoang Van Thai, Dich went to Combat Sector 4, Thach went up to Thai Nguyen-Bac Can, and Sam, Khang, and Tuong were placed on a long line from Phuc Yen up to Phu Tho, locales that needed to quickly put down the activities of the [Vietnamese] Nationalist Party and "Viet Cach" [Vietnam Revolutionary] cliques.

Near the end of the year, the Cryptographic Section received two more people: Cde Nguyen Hai Hac, graduate of the Higher Agricultural School, home in Hanoi, and Cde Tung Anh^[7] from Quang Ngai, who came at the invitation of the military organization there.

As of this point, people working in the Cryptographic Section were temporaries. Some arriving before, some later, these were the comrades present in the early stage of the formation of the army cryptographic branch. A small, close-knit and affectionate family, united to help each other, with a clear sense of responsibility and personal honor to respond to the requirements of the revolution and the army, these comrades shouldered a tough, essential job, doing the spade work for a technical branch of the PAVN.

Initial feelings of inadequacy passed quickly. With respect to cryptography, it could be said that the resources of the comrades at this stage were simply revolutionary zeal and enthusiasm, together with a book, The Basic Principles of Cryptography^[8] in French, which had come apart, and some two or three Boy Scout riddle games^[9] – this was the level of knowledge at this stage.^[1]

The comrades divided among themselves going to meet comrades who had experience in covert activities inside and outside our country, seeking to learn from their experience; searching for a few types of [cipher] keys, easy to remember, easy to use; a few methods of writing secret letters; all sorts of text books in the Vietnamese language that could be consulted in research. The comrades regularly said to one another, "Now we've really got to get back to our mother tongue!" Not long before this, every time one spoke up in class it had to be in the language of the French "mother country," and now, how eagerly they were going to work in the Vietnamese tongue! There were young men and women at this time, under the age of twenty, coming to grasp the fact that Vietnamese had many alphabets and knowing which, encountered many, especially in literature. The [cryptographic] concept of "frequency" emerged through the practice of enciphering and deciphering.

At the suggestion and urging of Cde Hoang Dao Thuy, after about a week, Cde Ta Quang De researched a system to use to write and read secret letters.^[10] Per instructions from Cde Hoang Van Thai, this cryptographic system was given to a command comrade on the Vinh Yen front to use for liaison. Some days later, Cde Hoang Van Thai gave Cde De a secret letter to encipher for sending to the Vinh Yen front. The content was a short section, but written out to produce a full page. When signing the message form, the comrade chief of the General Staff observed, "First, this way you have to write a lot, use up a lot of time, a lot of paper; second, it's rather difficult to ensure a fit between what's valid and what's false, thus the end is revealed; and, third, it's not handy for message transmission."

From these observations and exchanges with the fellows in the Cryptographic Section, Cde De came up with a different method: a method of enciphering each alphabetical letter – simple in use, a neat, compact chart. In using these systems for monoalphabetic [doc bieu] substitution and transposition, by close observation of a number of cryptograms, the comrades subjected them to detailed scrutiny and saw a number of points arise: Concerning monoalphabetic substitution: the repetition of the plain-cipher values followed a basic form. Some consonants and vowels in the Vietnamese language, represented by two letters, caused the frequency to rise very clearly.

Enciphering by transposition, using a literal key or a digital key: If enciphering by simple letter transposition, then the number of letters of the enciphered message would be equal to the number of letters of the plaintext message. These conditions resulted in cryptography that would not ensure tight secrecy, easily exposed to the eye of an enemy with much experience in cryptanalysis. Each individual arrived at the conclusion that the systems being used would not yet meet the requirement to ensure secrecy, their degree of security was at a rather low level – we had to quickly research different systems to replace them.

Based on experience with monoalphabetic substitution cipher, Cde Ta Quang De discussed with the people in the Section finding a way to change the system and change the key. Above all else, to produce some way that the appearance of the cryptogram was not dependent upon the appearance of the plaintext message – when our people looked at the cipher text they only saw it in its entirety, whereas clusters of letters differed from others in frequency and quantity. Then, in enciphering, to carry out a key change, a chart or direction change, even right in a message. The concrete method would have to have a composite chart, composed of many contrasting systems, each system with an individual key. After a period of searching and exchanging views within the Section, Cde De came up with a new type of system. The first columnar chart system had succeeded, with Cdes Hoang Van Thai and Hoang Dao Thuy agreeing to introduce its use to replace the systems that had been used for so long. Once the cryptographic systems had been typed up, Cde Hoang Van Thai sent a message to the sector chiefs to select dependable people to come to HQ to receive the system and listen to directions for use. A few days later, Van Tien Dzung came from Chi Ne bringing along a cryptographic cadre, then Le Van Suu from Intersector 4, Vu Hien from Haiphong, Le Quang Hoa, Hoang Minh Thao, et al., and the other units in turn selected cryptographers from their units to receive the system.

According to the principles of this system, each cryptogram had to be changed into a fixed number of columns. Each column had its own key and in order to be certain of ensuring secrecy, each key was fixed for many cryptographic values [ký hiêu mât]. At first, many comrades were a bit perplexed, suggesting that use of simple transposition would also ensure secrecy. The comrades in the section had to stand their ground in explaining, and the others finally became truly unanimous. After a period of use, enciphering and deciphering many times, the work became routine. The comrades in the research team continued to realize an additional step, regulating the movement of the cipher strip [

One might say, from forms of "leave out the false, what's left is valid" in order to read secret letters (not yet forms that could properly be called cryptosystems) and monoalphabetic substitution and transposition by pattern, we quickly moved to chart systems using irregularly arranged values with many columns and many keys. These chart systems, given the educational and technical conditions of our society, generally speaking, and our army, specifically, at that time, seemed relatively suitable and achieved a notable level of meeting the requirement to serve guidance and command.

The work came fast and furious, the activity of the Vietnamese Nationalist Party in the provinces of Phu Tho and old Vinh Phuc being reported continuously by message. Then the Nam Bo resistance, the French colonialists hiding behind the British military, swarming into Indochina and attacking and occupying many cities. The endless struggles of great fortitude of our Southern compatriots took place daily. So as to quickly grasp the situation and issue guidance for coping with the enemy and foreign aggressors, the Cryptographic Section, along with the communications-liaison organizations, worked day and night. From the end of September, through October – November 1945, the volume of secret messages increased very rapidly. The matter of telegraphic language frequency posed a need for research into a method of scientific calculation. (Initially, this matter had to be done by guessing, for there was a time-sensitive need to satisfy the most pressing, urgent requirement for the service of command.) The clear part of the cryptographic system form received concentrated research in construction. Combining experience and research and the use of a columnar system that followed the principle of monoalphabetic substitution with a digital key, with personally searching out and consulting foreign documents in order to apply international principles suitable to the special aspects of Vietnamese telegraphic spelling, Cde Dinh Loan Thuyen and colleagues produced a Vietnamese 676-cell [26×26] chart. The system was constructed according to the method of polyalphabetic [đa biêu] substitution encipherment of word components. After completion of the system, it was quickly put into use.

Implementing a directive from the Chief of the General Staff, the Cryptographic Section designated people to convey the system to a number of places lacking the means to receive it. On the first lunar new year's day after the August Revolution, Cde Thuyen was ordered in turn to convey the system and directions for use of the 676-cell chart to the units from Phu Ly to Binh Dinh. Vis-a-vis Nam Bo, that theater of war received concentrated assistance from the whole country: from October 1945, the Cryptographic Section quickly sent cipher models, carried by Cde Hoang Quoc Viet, to be handed over to the Sector [Xú'] committee, when the comrade, on behalf of the Standing [Committee] of the Central Party, went down and participated in the opening at the Sector Committee Conference.

A consciousness of the need for constantly changing keys, changing cipher strips, replacing systems dawned early-on among the comrades engaged in cryptography.

One day, around the end of 1945, the Second Bureau [Military Intelligence] sent over to the Cryptographic Section a number of enemy cryptograms. Although knowing nothing about cryptanalysis, the fellows nevertheless took a stab at it. The unexpected result was that the comrades decrypted a third of the cipher messages from a French army unit stationed in Upper Laos exchanging operational matters among themselves by means of a simple substitution system. This resulted in the Second Bureau comrades forming a high opinion of the expertise of the cryptographers. As for us, this small accomplishment in cryptanalysis had the effect of helping our people make up systems, even as it helped them in encrypting messages themselves.

In January 1946, in accordance with instructions from Central, the General Staff organizations were realigned. The cryptographic organization was split off from the Communications-Liaison Bureau. For the political, routine, and administrative aspects, [it would be] directly subordinate to the General Staff secretariat; for speciality professional knowledge that was the essence of its task, directly subordinate to the comrade Chief of the General Staff. The main office of the bureau was moved to No. 26 Hang Bai (a sign in front of the door of the office said "Bureau of Secret Messages" the sectors [khu], the cryptographic organization was called "Department [ty] of Secret Messages," or "Department of Cryptography." In Sector 1, the Department of Secret Messages was organized directly subordinate to the regional command post secretariat, while in the regiments cryptographic teams were directly subordinate to the regimental command section. In sectors 4 and 5, the cryptographic organizations were called Department of Cryptography, directly subordinate to the secretariat or staff organizations, with cryptographic teams in the regiments.

In March 1946, Cde Ta Quang De became a liaison control officer between the Vietnamese and French sides.^[11] Cde Hoang Van Dong became Chief of the Cryptographic Bureau. Research into cryptographic technique was undertaken by Cdes Dinh Loan Thuyen and Hoang Van Dong.

At this time, the 676-cell code chart was improved, fixed strips replaced by movable strips, raising the level of cryptographic security. The content of the chart was added to by compound words [tiêng kép] and phrases [

At the beginning of 1946, Cde Thuyen received the task of preparing a system to ensure cryptographic liaison between our government's delegation at the Da Lat preparatory conference and the General Staff. Realizing the degree of importance of the matter in our foreign relations struggle with the French, to ensure the secrecy of policy instruction laid down to our delegation by the party and government, Cde Thuyen concentrated all of his efforts into making a system. The good things of the chart form were incorporated into a chart system made solely to serve the Da Lat conference. The leadership comrades also knew that, at this conference, the French side had brought along a guy who was a specialist in cryptanalysis, with equipment to search out our secret information. Having received the first two messages sent back from the Da Lat conference, Cde Thuyen personally broke them out and was flabbergasted: the person enciphering the messages had not conformed closely to the regulations concerning the technique that had been conveyed – the information we were sending could easily be uncovered by the enemy. The Cryptographic Bureau at once suggested to Cde Hoang Van Thai suspending the use of this type of system. During the course of working for the previous half year, Cdes Dam, Thuyen, and Dong were tormented with mixed feelings, principally over whether the cryptography they were using was really tightly ensuring military secrecy or not. After reading some documents that had been received, the comrades knew that those people were still enciphering and deciphering by machine, and especially that they were still using equipment that made it very easy to discover the system and key. Thus they had to be even stricter with themselves, although believing firmly in the sense of loyal service by the young men and women performing cryptography, as far as their country was concerned, the general standard was still low and capacity for carelessness no small matter. The comrades discussed with the young men and women in the section a cryptanalytic test of an enciphered message, setting aside knowledge of system and key, to see if it could be made out. But, although they worked out the system and key, once, when they did not have system and key at hand, no one could make out anything at all. Thus day by day and week by week, continuing this sort of thing, they listened intently and watched for signs of any leaks in secrecy, and they felt reassured.

In April 1946, in order to increase the building and creation of conditions for the cryptographic organization to fulfill its mission in situations that had become more urgent daily, the cryptographic organization of the General Staff was supplemented by comrades Ho Ton Vinh, Hoang Don, Hoang Tuyen, Luong Dzan, Hoang Dzanh Cha – Cde Ho Ton Vinh (alias Hoang Duc Ton) was one of the first three Communist party members in the General Staff organization and was sent to the cryptographic organization as a supplementee. These young men were introduced by leadership and command comrades of high standing.

Along with the building and strengthening of the cryptographic organization at Central, the training of cryptographic cadre to expand the system of cryptography and strengthen the units was fully appreciated. As a matter of urgency, the General Staff cryptographic organization prepared to open a mass class to train cryptographic cadre to supplement the cryptographic organizations at lower echelons. The task of research and compilation of [cryptographic] material to teach in this class was given to Cdes Dinh Loan Thuyen, Hoang Van Dong, and Hoang Dzanh Cha. Although they encountered many difficulties, the comrades diligently consulted, researched, and compiled a quantity of documents concerning the science and techniques of cryptography.

Material compiled by Cdes Hoang Van Dong and Dinh Loan Thuyen first-off comprised basic theoretical content and instruction in the use of cryptographic systems. Cde Hoang Zanh Cha researched and compiled the statistical content concerning Vietnamese language frequency, in order to serve in constructing cryptographic systems. These were also the formative works in the sphere of research into the science of cryptographic technique on the part of the army cryptographic branch.

After preparing sufficient documentary content to cover all aspects, the General Staff decided in September 1946 to open the first class in the army to train cryptographic cadre: it was named "The Hoang Dzieu Class." Sessions took place at No. 7 On Nhu Hau Street (now Nguyen Gia Thieu Street), Hanoi, under Cdes Hoang Van Dong, Hoang Dzanh Cha, and Ho Ton Vinh. Cde Hoang Van Dong was in general charge and bore responsibility for teaching cryptographic principles. Cde Ho Ton Vinh was responsible for political leadership and thought and bore responsibility for teaching political matters. Cde Hoang Dzanh Cha bore responsibility for teaching the methods of researching the frequency of the Vietnamese language and the use of cryptographic systems. Twenty students from the combat sectors and units in Viet Bac, Trung Bo, and the Southern Viet Nam Resistance Committee (in Quang Ngai) were selected to attend the class. Nam Bo, hindered by transportation, was unable to send up people to attend. Before getting into specialized study, the students had to grasp the mission thoroughly, clearly define ideology, and understand the "must-do's and the musn't-do's" of the work of people performing the task of cryptography. Beyond the basic content of the syllabus, the class also received an additional introduction to fundamental knowledge of the cryptology of the world and practiced a number of our forms of cryptography. After more than a month of study, achieving good results, the class came to an end. The students returned to the units, becoming the nucleus of building cryptographic organizations in the combat sectors [chien khu]. Some comrades were retained to supplement the General Staff cryptographic organization, namely, Nguyen Chanh Can, Hoang Manh Tuan, Vu To, Vu Duc Minh, and Nguyen Van Dzanh (Ho Quang Chinh) – Cde Ngo Vi Thien was sent to supplement Combat Sector 1; Cde Tran Dac Quy to Combat Sector 2; Cde Le Hai to Combat Sector 3; Cde Van An to Combat Sector 4; Cde Dong Tam to Combat Sector 5; Cde Tung Anh to Combat Sector 6, etc.

In May 1946, in order to implement Ministry of National Defense instructions to organize reliable and secure communications-liaison nationwide, the cryptographic organization of the General Staff convened the first cryptographic conference. The conference discussed the tasks of cryptography and secrecy, and the delivery and receipt of cryptographic systems. Comrades in charge of the cryptographic organization in the combat sectors and fronts came to attend (except for cryptographic cadre-in-charge in Sector 5 and Nam Bo, who could not get back to attend). The conference received a visit and teaching from the Cde Chief of the General Staff, Hoang Van Thai. In August 1946, meeting again in the second military cryptographic conference in Hanoi, twenty-five delegates from Trung Ky [Annam] and Bac Ky [Tonkin] attended: the discussion was on cryptographic training. After the conference there was a five-day specialty training course.

Thus, together with resolute research, ingenuity, and expansion of the cryptographic net, having received the concern of the leadership and command cadre, the cryptographic organization urgently strove to train cryptographic cadre and personnel to supplement the units. From the beginning of December 1946, the cryptographic organization in the army had, by turns, organized in the combat sectors, the companies [chi doi], and a number of units, army-wide, participating in "maintaining contact between the combat sectors, an essential condition for unified command," in the spirit of "Chi thi kháng chiêń kiên quôć" ("Instructions for Resistance in Founding a Nation"), from the Executive Committee of the Central Party (25 November 1945).

Notwithstanding, during this time we had not yet come out with concrete regulations, so getting and using cryptographic cadre and personnel remained hit or miss. The cryptographic organizations in the sectors were not able to manage the total number of personnel under their authority. The command organizations routinely transferred cryptographic personnel to other assignments, or assigned them work outside the sphere of their technical speciality. This situation worked counter to the ideology of a number of cryptographic cadre and personnel, principally at the regimental and company level. A number of cryptographic personnel had no stomach for the job, and requested direct combat or transfer to some other duty.

After the August revolution succeeded in giving birth to a people's democratic nation, under circumstances in which research, ingenuity, and expansion of the cryptographic net competed with providing for the training and development of cadre and personnel and solidly building a system of organization, the army cryptographic organization had to ensure the transmission of the content of leadership, direction, and command of the various echelons through the communication media, responsive to the urgent mission situation of our homeland. The cryptographic organizations from the 16th parallel^[2] up concentrated on serving leadership and command coping with the tricks and schemes and the actions to oppose and destroy or overturn the revolutionary authority on the part of the Chiang bunch and domestic reactionary gangs. The cryptographic organizations in Hanoi, Phuc Yen, Vinh Yen, and Phu Tho ensured the transmission of secret messages directing the struggle, and suppressing subversive acts by the Nguyen Hai Than, Nguyen Tuong Tam, and Vu Hong Khanh gangs; secret message directed provisional political arrangements between the Viet Minh front and the Viet Cach and Viet Quoc.

On 23 September 1945, when the French colonialists, aided by the British, opened fire and occupied Nam Bo, striking and taking over communication centers, the organizations and armed units of Nam Bo overcame obstacles to protect the evacuation of radio stations into bases, ensuring liaison within the region [vung] and with Central.

At 0815 on 25 September 1945, Nam Bo Cryptographic enciphered a message reporting to Central Party and the government concerning the resolution of the Nam Bo Sector Committee [xú' uy], determined to resist the French colonialists. At 1010 the same day, the comrades received and deciphered the Central Party instruction agreeing with the resolution of the Sector Committee and the Nam Bo Resistance Committee. The cryptographic units in the South ensured the transmittal of the secret messages of the High Command, instructing the Southern military groups to advance and serve in the resistance struggle against the French in the South.

The task of enciphering and deciphering messages at this period was still elementary, but a first step toward an orderly routine. A number of regulations on enciphering and deciphering were issued, aimed at protecting technical secrets and the content of secret messages. All cryptographic materials had to be reduced to bare bones and constantly kept at the side of the cryptographer. The element enciphering and deciphering messages was to be compartmented by net, and not to express curiosity to know the contents of the work of another, between elements, or between each individual in his special compartment. Ordinarily, messages were transmitted by radio or post. In the beginning, for messages sent by post, the procedure was that the place sending and the place receiving were written in the clear, with the content alternating, some sections clear, some in cipher. If the messages was going by radio, then the sending place, receiving place, and precedence were written in French. Upon reexamination, these arrangements were seen not to be of value in protecting secrecy, thus gradually redone. Because going and coming was difficult, the replacement of the types of systems in use was not effected at an exact time, nor were new systems distributed in timely fashion.

The situation became more urgent with every passing day. On 19 October 1946 our Party's army-wide military affairs conference resolved clearly that "We must conclude absolutely that, sooner or later, the French will strike us and we absolutely must strike the French." As a result, at the General Staff and the units, the volume of secret messages to encipher and decipher increased daily, with higher precedences.

On 20 November 1946, the French colonialists opened fire, attacking and occupying Hai Phong and Lang Son, increasing the landing of troops at Da Nang, and staging many provocations in Hanoi. The army cryptographic organizations ensured timely encipherment and decipherment of the leadership guidance and command content from Central and the High Command to the theaters, and enciphered and deciphered the situation reports of the theaters to Central. Thus the operational experiences at Hai Phong, Lang Son, Nam Bo, etc., were quickly sent to other regions to study and apply.

On 16 December 1946, the General Staff cryptographic organization was tasked to encipher a message from the Standing Committee of Central Party to the provincial party HQ in the South, with contents as follows: "According to the situation on the French side and the greediness of the colonialists, there is only one global war, protracted, sharp, with difficulties newly resolved for the sovereignty of Viet Nam. The Party guideline is that it is absolutely essential to prepare. We must have good cadre and masses. Fully understand protracted resistance. Somehow victory will come to us."

In accordance with instructions from Cde Hoang Van Thai, the General Staff cryptographic organization reexamined the cryptographic system arrangements in the units and aligned and allocated cadre and personnel prepared and on duty to perform the mission, so as to quickly encipher or decipher instructions and operational orders of the General Staff, going to the combat sectors and the fronts.

Before the French military provocations in Hanoi took place, the General Staff cryptographic organization, along with the General Staff organizations, moved from 26 Hang Bai Street out to Thai Ha Ap (some 200 meters southwest of Dong Da Hill).

On the night of 18 December 1946, the French military command sent a letter of ultimatum to our government, calling for the stripping of weapons of self-defense and the occupation of the Hanoi Office of Public Security.

Implementing a resolution of the Central Party Standing Committee, the High Command [

At 0800 on the morning of 19 December, Cde Hoang Van Dong and Cde Luong Dzan received the task of enciphering an immediate message (received with a note and signature of Cde Hoang Van Thai, "need to encipher at once") going to the units, text as follows:

On the heels of which, this order from the Minister of National Defense/Commander-in-Chief to the entire military:

The two message texts above were speedily encrypted and sent to the combat sectors and fronts.

Immediately thereafter, flash [hoa tôóc] messages were enciphered and sent to combat sectors 1, 2, 3, 4, 11 and to Da Nang, with the request that they be in the hands of the command comrades of the sectors and fronts prior to 0930 on 19 December 1946 in order to implement the order to open fire and strike the enemy on a coordinated basis on the theaters of war at the precise hour determined, contents as follows:

"The freight will arrive at 1800 hours 21 December 1946. The freight carries the code symbol A + 2 and B-2. Pay attention and meet the freight at the exact time."

Code symbols A + 2 and B-2 were previously established by the General Staff with the sectors. A was the hour, B was the day of the attack. A + 2 was [the stated time,] 1800, plus 2, or 2000 hours. B-2 was [the stated day,] 21 December minus 2, or the 19th.

At 2000 hours on 19 December 1946, at the High Command [

At exactly 2003 on 19 December 1946, electric lights in the sky over Hanoi suddenly went out. Salvos resounded from the fortresses at Lang, Xuan Canh, Xuan Tao, etc., raining down on the heads of the French aggressors in the strongpoints they had set up in the city.

The Cde Commander-in-Chief was quite satisfied with the results of sending the combat orders of Central and the High Command to the units, guaranteeing timeliness, secrecy, and precision in terms of command organization and technical means which were limited.

Keeping pace with the militia of the Hanoi capital, the army and citizens in the large cities and regions, such as Nam Dinh, Vinh, Hue, Da Nang, Bac Giang, Bac Ninh, Hai Dzuong, etc., also opened fire, striking the French aggressor forces. The military cryptographic organizations in these places ensured accurate, secret, and timely encipherment and decipherment of orders and combat instructions from upper echelons.

Thus having taken the step to war, the army cryptographic organizations, from cryptographic organizations of the combat sectors, fronts, and especially the cryptographic organizations of the Capital, Thang Long, Son Tay, Ha Dong, etc., regiments requirements, did a good job of accomplishing their task of ensuring the service of leadership and command in striking the French aggressors, although the units lacked people and technical means. Via the system of cryptography and communications, the Ministry of National Defense, the High Command [Tong tu lenh], and the General Staff were able to grasp the situation in the theaters of war, and leadership, direction, and command from the Central Party and the army were timely, vis-à-vis the regions [dia phuong] and units throughout the entirety of the nation.

Having come through fifteen months of building organization and technique, while having to serve in ensuring the secrecy of the content of leadership and command from the Party and army via the means of communication, although faced by very many difficulties in this initial period, the army cryptographic branch strove upward to do a good job of accomplishing their mission, handed to them by the Party and army. The principal determining factor was the concern shown by the upper echelon leadership cadre, always creating [favorable] conditions and wholeheartedly assisting the army cryptographic organization in building organization, technique, and its job of serving leadership and command. Cdes Pham Van Dong, Vo Nguyen Giap, and Hoang Van Thai, etc., in the first stage of establishing the army cryptographic branch, not only provided concrete guidance concerning the direction of the job, but also personally introduced and assisted in the selection of trustworthy people – personally commented, gave suggestions, sought out documents for the cryptographic organization. After the July-August 1946 Fontainebleau Conference, Cde Pham Van Dong returned, bringing a French book on cryptography, Le Chiffrement et le dechiffrement, by Jean Bubois, and passed it to the cryptographic organization for research and reference. Although these accomplishments were only the first step, they demonstrated patriotism, self-reliant will to create technique, and minds determined to accomplish the mission, on the part of the initial contingent of army cryptographic cadre and personnel.

These results and accomplishments have extreme significance, in that they helped the branch extract lessons from real life experience and participate in the building and combat of the branch.

^[3]

^[4]

^[5]

^[6]

^[7]

^[8]

^[9]

^[10]

^[11]