In January 1917, British cryptographers deciphered a telegram from German Foreign Minister Arthur Zimmermann to the German Minister to Mexico, Heinrich von Eckhardt. In that telegram, Zimmermann offered United States territory to Mexico in return for joining the German cause. This message helped draw the United States into the war and thus changed the course of history. The ciphertext and decoded message of Zimmermann is shown in Figure-2.1. The challenge was the encrypted message had many missing ciphertext. In spite of missing encrypted text, the British cryptographic office known as Room 40 decoded the Zimmermann Telegram and handed it over to the United States in lateFebruary 1917.

NZQLI XSFIXSVH ZIV ZG LWWH DRGS ZFGSLIRGRVH LEVI GSV ZHGIZAVMVXZ EZXXRMV, DRGS IVORTRLFH OVZWVIH GVOORMT KZIRHSRLMVIH GSVB ZIV VMGRGOVW GL IVJFVHG Z WRUUVIVMG QZY YFG GSV UVWVIZO TLEVIMNVMG HZBRMT NLHG KVLKOV DLMG SZEV Z XSLRXV. IVORTRLFH XLMXVIMH ZYLFG GSV ZHGIZAVMVXZ EZ_XRMV ZIRHV UILN RGH FHV LU ZYLIGVW UVGZO XVOOH RM GSV WVEVOLKNVMG KILXVHH, DSRXS RH XLNNLM HXRVMGR_RX KIZXGRXV GSZG HLNV XSIR_GRZMH URMW LYQVXGRLMZYOV. GSV HGLFHS XLFOW UIFHGIZGV LI WVOZB ZGGVNKGH GL RMLXFOZGV GSV XLFMGIB ZTZRMHG UFIGSVI XLE_W-19 LFGYIVZPH ZMW OLXPWL_MH ZH ZFGSLIRGRVH KIVKZIV GL HGZI_ GSV EZXXRMV ILOOLFG OZGVI GSRH NLMGS.

Using frequency analysis technique, you need to show step-by-step processes to Decipher and find out the actual message. Use the English alphabet frequency count as shown in Figure 2.2. Please note that no marks will be given if only plaintext is shown without detailed steps.

TELIXIRAM KRIVED. WESTERN UNION MIC TELBORAM TO Wha le Gallery FROM ud from London, 6747. ry RAL 2017 LS 6% GERMIS LEGATION VIO CITY 150 1900 2501 1155 10 17214 6413131 1814 SI 1004 19806 34414850 DONE CS 113111000 1001 112001 50005 335 1910 1985 11 111010101473 104 105 How 1931 1930 1939 1233 48 415 05 19 1918 1919 1910 361 1901 07895 103 3647 ETC 10 3 154 16100 15 22001 171 21001 1011014530110145 e 2012100 943 304 305 13.00 18500 100 1334 BOLO 1978 ? cler 2 1 3 134 134 135 136 13295 1043 1485448831737 134 11367 BIZ 4 1 ser 185 10500 x 55451 1941 19 150 1990 9850 90 096 101 5841170 11845 194 11104 Tre 1109110 1043 Des sep MESTO. *s intend to begin on the first of February unreotricted submarine wartore. We shall endeavor In spite of this to keep the United States of nerica neutre. In the event of the not muce Ing. sake Mexico proposal of alliance on the Following houlemoke wat together, sko pesce together, generous fiscal support and an under standing on our part that mexico in to reconquer the loot territory in Texas, New Mexico, Arns. The settlement in detail is left to you. You will inform the President of the above seat secretly as soon the outbreak of war with the Unit46 States of America de certain and add the sucosetion that he should, on his own initiative, Japan to nedote dherence and at the same sine mediate between Japan and buraslyse. Ple coll the Presidenta sttention to the fact that the ruthleso esployment of our cubrindo now offers the prospect of compelling alone in few month to me proc. n. Dr. (a) Encoded Message (b) Decoded Message Figure-2.1: Zimmermann Telegram In this task, you have to decrypt an encrypted message. However, here we have encrypted a long English message a bit differently. Every single alphabet in the message has been substituted by another unique alphabet. While the encrypted message was captured, some of the alphabets were missing. A missing encrypted alphabet is marked as '_'. The encrypted message is shown below: NZQLI XSFIXSVH ZIV ZG LWWH DRGS ZFGSLIRGRVH LEVI GSV ZHGIZAVMVXZ EZXXRMV, DRGS IVORTRLFH OVZWVIH GVOORMT KZIRHSRLMVIH GSVB ZIV VMGRGOVW GL IVJFVHG Z WRUUVIVMG QZY YFG GSV UVWVIZO TLEVIMNVMG HZBRMT NLHG KVLKOV DLM'G SZEV Z XSLRXV. IVORTRLFH XLMXVIMH ZYLFG GSV ZHGIZAVMVXZ EZ XRMV ZIRHV UILN RGH FHV LU ZYLIGVW UVGZO XVOOH RM GSV WVEVOLKNVMG KILXVHH, DSRXS RH XLNNLM HXRVMGR RX KIZXGRXV GSZG HLNV XSIR GRZMH URMW LYQVXGRLMZYOV. GSV HGLFHS XLFOW UIFHGIZGV LI WVOZB ZGGVNKGH GL RMLXFOZGV GSV XLFMGIB ZTZRMHG UFIGSVI XLE_W-19 LFGYIVZPH ZMW OLXPWL_MH ZH ZFGSLIRGRVH KIVKZIV GL HGZI_GSV EZXXRMV ILOOLFG OZGVI GSRH NLMGS. E A O 1 N S H H R D L U 12.7 9.1 8.2 7.5 7.0 6.7 6.3 6.1 6.0 4.3 4.0 2.8 2.8 M w F Y G P B VK X N 2.4 2.4 22 2.0 2.0 1.9 1.5 1.0 0.8 0.2 0.2 0.1 0.1 Figure-2.2: English Alphabet Frequency Count TELIXIRAM KRIVED. WESTERN UNION MIC TELBORAM TO Wha le Gallery FROM ud from London, 6747. ry RAL 2017 LS 6% GERMIS LEGATION VIO CITY 150 1900 2501 1155 10 17214 6413131 1814 SI 1004 19806 34414850 DONE CS 113111000 1001 112001 50005 335 1910 1985 11 111010101473 104 105 How 1931 1930 1939 1233 48 415 05 19 1918 1919 1910 361 1901 07895 103 3647 ETC 10 3 154 16100 15 22001 171 21001 1011014530110145 e 2012100 943 304 305 13.00 18500 100 1334 BOLO 1978 ? cler 2 1 3 134 134 135 136 13295 1043 1485448831737 134 11367 BIZ 4 1 ser 185 10500 x 55451 1941 19 150 1990 9850 90 096 101 5841170 11845 194 11104 Tre 1109110 1043 Des sep MESTO. *s intend to begin on the first of February unreotricted submarine wartore. We shall endeavor In spite of this to keep the United States of nerica neutre. In the event of the not muce Ing. sake Mexico proposal of alliance on the Following houlemoke wat together, sko pesce together, generous fiscal support and an under standing on our part that mexico in to reconquer the loot territory in Texas, New Mexico, Arns. The settlement in detail is left to you. You will inform the President of the above seat secretly as soon the outbreak of war with the Unit46 States of America de certain and add the sucosetion that he should, on his own initiative, Japan to nedote dherence and at the same sine mediate between Japan and buraslyse. Ple coll the Presidenta sttention to the fact that the ruthleso esployment of our cubrindo now offers the prospect of compelling alone in few month to me proc. n. Dr. (a) Encoded Message (b) Decoded Message Figure-2.1: Zimmermann Telegram In this task, you have to decrypt an encrypted message. However, here we have encrypted a long English message a bit differently. Every single alphabet in the message has been substituted by another unique alphabet. While the encrypted message was captured, some of the alphabets were missing. A missing encrypted alphabet is marked as '_'. The encrypted message is shown below: NZQLI XSFIXSVH ZIV ZG LWWH DRGS ZFGSLIRGRVH LEVI GSV ZHGIZAVMVXZ EZXXRMV, DRGS IVORTRLFH OVZWVIH GVOORMT KZIRHSRLMVIH GSVB ZIV VMGRGOVW GL IVJFVHG Z WRUUVIVMG QZY YFG GSV UVWVIZO TLEVIMNVMG HZBRMT NLHG KVLKOV DLM'G SZEV Z XSLRXV. IVORTRLFH XLMXVIMH ZYLFG GSV ZHGIZAVMVXZ EZ XRMV ZIRHV UILN RGH FHV LU ZYLIGVW UVGZO XVOOH RM GSV WVEVOLKNVMG KILXVHH, DSRXS RH XLNNLM HXRVMGR RX KIZXGRXV GSZG HLNV XSIR GRZMH URMW LYQVXGRLMZYOV. GSV HGLFHS XLFOW UIFHGIZGV LI WVOZB ZGGVNKGH GL RMLXFOZGV GSV XLFMGIB ZTZRMHG UFIGSVI XLE_W-19 LFGYIVZPH ZMW OLXPWL_MH ZH ZFGSLIRGRVH KIVKZIV GL HGZI_GSV EZXXRMV ILOOLFG OZGVI GSRH NLMGS. E A O 1 N S H H R D L U 12.7 9.1 8.2 7.5 7.0 6.7 6.3 6.1 6.0 4.3 4.0 2.8 2.8 M w F Y G P B VK X N 2.4 2.4 22 2.0 2.0 1.9 1.5 1.0 0.8 0.2 0.2 0.1 0.1 Figure-2.2: English Alphabet Frequency Count