Reja Kirish II. Asosiy qism Jeferson kriptografik shifrlash qurilmasi. Uning ishlash prinspi Hagelin m-209 kriptografik shifrlash qurilmasi haqida umumiy tushunchalar. Enigma shifrlash qurilmasi. Shifrlash jarayonida bajaradigan algoritm


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Mavzu: Axborotni kriptografik muhofaza qilish qurilmalari, ularda qo’llanilgan kriptografik usullar (Jefferson, Enigma, Hagelin M-209 kabi qurilmalar)


Bajardi: Bekbutayev G‘ayrat

Toshkent-2020

Reja


  1. Kirish

II. Asosiy qism

2.1. Jeferson kriptografik shifrlash qurilmasi. Uning ishlash prinspi

2.2. Hagelin M-209 kriptografik shifrlash qurilmasi haqida umumiy tushunchalar.

2.3. Enigma shifrlash qurilmasi. Shifrlash jarayonida bajaradigan algoritm.

III. Xulosa.

IV. Foydalanilgan adabiyotlar



Kirish

Elektron ko‘rinishdagi ma’lumotlarni hajmini ortishi, uni saqlash bilan bog‘liq bo‘lgan muammolar hajmini ham ortishiga olib keladi. Ushbu muammolarni hal qilishda mavjud bo‘lgan usullar esa, kundan-kunga yangilanaveradi. Shunga qarmasdan axborot xavfsizligini ta'minlashda qadimda ham foydalanilagan va hozirda ham foydalanilayotgan usullardan biri bu - kriptografik himoya usullaridir. Kriptografik himoya usullari o‘zining ishonchliligi, samaradorligi va foydalanish darajasi qamrovi kengligi bilan boshqa usullardan farq qiladi. Hozirda axborot xavfsizligini ta’minlashning har bir jabhasida kriptografik usullardan foydalanilmoqda. Bu esa uning muhimligidan darak beradi.

Kriptografiya - axborotlarni aslidan o‘zgartirilgan holatga akslantirish uslublarini topish va takomillashtirish bilan shug‘ullanadi. Dastlabki sistemalashgan kriptografik uslublar eramiz boshida, Yuliy Sezarning ish yuritish yozishmalarida uchraydi. U, biror ma’lumotni maxfiy holda, biror kishiga yetkazmoqchi bo‘lsa, alfavitning birinchi harfini alfavitning to‘rtinchi harfi bilan, ikkinchisini beshinchisi bilan va hokazo shu tartibda almashtirib matnning asli holatidan shifrlangan matn holatiga o‘tkazgan.

Axborotlarning muhofazasi masalalari bilan kriptologiya (kryptos- maxfiy, logos- ilm) fani shug‘ullanadi. Kriptologiya maqsadlari o‘zaro qarama-qarshi bo‘lgan ikki yo‘nalishga ega: - kriptografiya va kriptoanaliz.

Kriptografiyaning ochiq ma’lumotlarni shifrlash masalalarini matematik uslublari bilan shug‘ullanishi to‘g‘risida yuqorida aytib o‘tildi.

Kriptoanaliz esa shifrlash uslubini (kalitini yoki algoritmini) bilmagan holda shifrlangan ma’lumotni asli holatini (mos keluvchi ochiq ma'lumotni) topish masalalarini yechish bilan shug‘ullanadi.

Hozirgi zamon kriptografiyasi quyidagi to‘rtta bo‘limni o‘z ichiga oladi:

1) Simmetrik kriptotizimlar.

2) Ochiq kalit algoritmiga asoslangan kriptotizimlar.

3) Elektron raqamli imzo kriptotizimlari.

4) Kriptotizimlar uchun kriptobardoshli kalitlarni ishlab chiqish va ulardan foydalanishni boshqarish.

Kriptografik uslublardan foydalanishning asosiy yo‘nalishlari: maxfiy ma’lumotlarni ochiq aloqa kanali bo‘yicha muhofaza qilgan holda uzatish, ularning haqiqiyligini ta’minlash, axborotlarni (elektron hujjatlarni, elektron ma’lumotlar jamg‘armasini) kompyuterlar tizimi xotirasida shifrlangan holda saqlash va shu kabi masalalarning yechimlarini o‘z ichiga oladi.





    1. Jeferson kriptografik shifrlash qurilmasi. Uning ishlash prinspi

The Jefferson Disk is a manual polyalphabetic substitution cipher system, invented in 1795 by Thomas Jefferson, the 3rd President of the United States. The device was independently invented by Étienne Bazeries about one centry later, and is therefore also known as the Bazeries Cylinder. It later evolved into the M-94 cipher unit that was used by the US Army from 1922 to 1945 [1].

The device consists of an axle with 36 wooden discs, each of which holds the letters of the Latin alphabet on its circumference in a (differently) scrambled order. Each disc is identified by a unique number. The order in which the discs are arranged on the axle, is known as the secret KEY and had to be pre-arranged between the parties.

Original Jefferson disks are extremely rare, as only very few were made and even less have survived. The image on the right shows an original one that is on public display at the NSA's National Cryptologic Museum at Fort Meade [1].



Photograph via Wikipedia [1]

Sending a message is pretty simple. The sender sets up the secret KEY (i.e. the order of the discs) and then rotates each of the wheels until the first 25 letters of the message are visible in a single row. He then rotates the set of discs by an arbitrary number of steps (other than zero) and reads of the resulting ciphertext. The ciphertext is then sent to the receipient by letter or telegram.

The recipient sets up the same secret KEY and aligns his wheels so that the ciphertext is readable on a particular row. He then rotates the axle by the same number of steps (offset) as the sender (in reverse direction), to read-off the plaintext. If the offset was unknown, he would simply check all rows to find a line that made sense (i.e. a line that produced readable text).

The Jefferson disk is also known as the Jefferson Wheel Cipher or the Bazeries Cylinder. It was invented in 1795 by the third US president, Thomas Jefferson, but became widely known after it was re-invented independently about a century later by Commandant Etienne Bazeries, whilst working for the Cipher Bureau of the French Ministry of Foreign Afairs [1]. The Jefferson disk was later refined to the M-94 that was used by the United States Army between 1923 and 1945 [2].

10-wheel replica

The Jefferson disk is best demonstrated by using a toy version of it. In 2009 and 2010, resonably priced plastic replicas of a 10-wheel Jefferson disk were sold on Ebay. The example below was created on such a replica. It has only 10 disks rather than 36, but is good enough for a demonstration. Detailed images of this toy are available at the bottom of this page.



Let's assume we want to transmit the message RETREATNOW. We would arrange the wheels so that this message is visible on one of the rows (see image #2).

We would then use the text from, say, the second row down, as the cipher text. It reads: WVCTSOKTDN. This cipher text is then transmitted to the receiver.

The receiver arranges the wheels so that the cipher text is readable on one of the rows, and then reads the plain text from the 2nd row up.

Typical view of the 'Jefferson' cipher wheel with the ruler on top

This system is, of course, not very safe if more than one line of text is encoded with the same order of the wheels, which is nearly always the case. Due to the repetitive nature of the key (i.e. the number and order of the wheels), it can easily be broken with hand methods. Nevertheless it was considered relatively strong at the time it was first used [1] .


  1. Wikipedia, Jefferson disk
    Retrieved August 2010.

  2. Wikipedia, M-94
    Retrieved September 2017.

  3. David Kahn, The Codebreakers
    1967. pp. 192-195.
Masalan, BEKBUTAYEV so‘zini shifrlab ko‘ramiz.Bu uchun bizga 10 ta dastlabki disk yetarli bo’ladi. Disklardagi harflar ixtiyoriy tartibda joylashgan bo‘ladi. Bizga 10 ta disklardagi harflar quyidagicha joylashgan bo‘lsin.

1:

2:

3:

4:

5:

6:

7:

8:

9:

10: Disklarni ochiq matn 1 qatorda hosil qilguncha aylantiramiz.
1: <B VIQ H KYPNTCRMOSFEZWAXJGDLU <

2: <E LNA C ZDTRXMJQOYHGVSFUWIKPB <

3: <K BDM A IZVRNSJUWFHTEQGYXPLOC <

4: <B SXQ Y IZMJWAORPLNDVHGFCUKTE <

5: <U OTS G JVDKCPMNZQWXYIHFRLABE <

6: <T AMK G HIWPNYCJBFZDRUSLOQXVE <

7: <A FDC E ONJQGWTHSPYBXIZULVKMR <

8: <Y GHB Q NOZUTWDCVRJLXKISEFAPM <

9: <E NYV U BMCQWAOIKZGJXPLTDSRFH <

10: <V RSC Z QKELMXYIHPUDNAJFBOWTG <


Shifrmatnga ega bo’lish uchun biz o‘ngdan 5 chi qatorni birlashitiramiz. Shifrmatn: HCAYGGEQUZ

Bob shifr matnini olgach, shifrmatnni hosil qilish uchun disklarni aylantiradi va keyin oddiy matnni shifrmatndan chapdan 5 chi qatorni o‘qiydi yoki shunchaki silindrni qatoriga qaraydi.


2.2. Hagelin M-209 kriptografik shifrlash qurilmasi haqida umumiy tushunchalar

One of Hagelin's biggest achievements was the sale of M-209 cipher machines to the US Army. Based on the C-36 / C-38 – a small cipher machine with 6 pin-wheels – the M-209 was adapted to meet the requirements of the US Army. Although Hagelin would normally build all machines in his factory in Stockholm (Sweden), he allowed the American's to build the machine under licence.



On 10 May 1940, Hagelin travelled on the last ship from Europe to the US, with two prototypes of the C-38 in his lugguage. It would eventually evolve into theM-209 and would become the largest sale of the so-called C-machines he ever made [3]. The machines were built at the Corona plant of the L.C. Smith typewriter company in Syracuse, with a daily output of up to 500 units.

The image on the right shows a typical M-209 as it was used by the US during WWII. It has 6 pin-wheels at the front, each with a different number of steps, and a cage with 27 bars at the rear.

As Hagelin couldn't return to Sweden during the war, he stayed in the US where he spent his time serviceing the BC cipher machines 1 of some American organisation. When he returned to Sweden in 1944, more than 50,000 M-209 machines had been built by the Smith Corona Typewriter Company and by the end of the war, this amount had nearly trippled to a staggering 140,000.

To allow production of the M-209 and the BC-38(shown on the right) in the US, and to avoid paying high tax fees in Sweden, Hagelin had transferred the full and royalty-free patent rights to the US Army, for the sum of US$ 3,023,410, of which US$ 2,548,225 was for him personally. The balance of US$ 475,185 went to the Hagelin Cryptograph Company (HCC) in Sweden [4]. 2

In return, the US Government granted Hagelin a royalty-free license for the production of M-209 and BC-38 machines and improvements thereof, so that he was still allowed to sell his invention.

It is worth noting that the machine did not provide absolute secrecy. During WWII, the Germans were able to decrypt a message in under 4 hours if they had received messages in depth 3 . This was not considered a problem however, as the M-209 was only used for tactical messages (e.g. field maneuvers) which had lost their significance by the time they were broken by the Germans.


  1. Boris Hagelin, The Story of Hagelin Cryptos
    English translation of the above. BCW Hagelin, Zug, Spring 1981. Later edited by David Kahn and published in Cryptologia, Volume 18, Issue 3, July 1994, pp 204-242.

  2. Collection of M-209 patents and license agreements
    A66684. Declassified by NSA on 11 June 2014 (EO 13526).

  3. Hans Stadlin, 100 Jahre Boris Hagelin 1892-1992 (German)
    Crypto AG. Crypto Hauszeitung Nr. 11. Jubilieumausgabe September 1992.

  4. Crypto AG, Crypto Magazine 2009, number 1
    Retrieved August 2009.


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