Decrypted_messages.txt

This file conatains the encrypted and decrypted messages at every stage till finding the final message.


After scanning the QRCode in the Vaccination certificate we get: 
R3JlYXQgam9iLiBKdWxpdXMgQ2Flc2VyIHdhcyBib3JuIGluIHRoZSAxMDAgQkM6ClBEQSBKQVRQIFlFTERBTiBHQVVPTVFXTkEgRU8gUERBIFdITERXWEFQTyBTRVBES1FQIEYKT1BYV09EUFNLUUxPTkNYUU5VSkVPTFhQV0FFSE1PVVpPRVFYWFZLVUpPV0JMTVdYUFFVSU9FTFBNWUtZRUhNT0dPS1lRWEFYS1lLRExZUVpZTFlIQVdXQkxNV1hRWUxXVldPWQ==

After converting the base64 string to raw data we get:

Great job. Julius Caeser was born in the 100 BC:
PDA JATP YELDAN GAUOMQWNA EO PDA WHLDWXAPO SEPDKQP F
OPXWODPSKQLONCXQNUJEOLXPWAEHMOUZOEQXXVKUJOWBLMWXPQUIOELPMYKYEHMOGOKYQXAXKYKDLYQZYLYHAWWBLMWXQYLWVWOY

After rotaing the character by 4 values after according to the order in alphabet we get:

Kviex nsf. Nypmyw Geiwiv aew fsvr mr xli 100 FG:
THE NEXT CIPHER KEYSQUARE IS THE ALPHABETS WITHOUT J
STBASHTWOUPSRGBURYNISPBTAEILQSYDSIUBBZOYNSAFPQABTUYMSIPTQCOCILQSKSOCUBEBOCOHPCUDCPCLEAAFPQABUCPAZASC

After decoding the next line using playfair cipher algorithm we get:
RSAENCRYPTNUMBERTWOHUNDREDFOURTYTHREEWITHNVALUEASTWOTHOUSANDFOURHUNDREDANDNINETEENANDEVALUEASELEVENX

Which says: RSA ENCRYPT NUMBER TWO HUNDRED FOURTY THREE WITH N VALUE AS TWO THOUSAND FOUR HUNDRED AND NINETEEN AND E VALUE AS ELEVEN X

After RSA encrypting the number 243 with n = 2419 and e = 11 we get:
(243^(11))%2419 = 1982

The pin to open the zipped file : 1982

After opening the zip file we have the text (from the textfile inside the zip): 
TM, DTZ KTZSI RJ😔. HTSLWFYX. YMNX NX YMJ JSILTFQ. TW NX NY?🤨

After rotating the character by 21 values according to the order in alphabet we get:
OH, YOU FOUND ME😔. CONGRATS. THIS IS THE ENDGOAL. OR IS IT?🤨


<--- The final message = OH, YOU FOUND ME😔. CONGRATS. THIS IS THE ENDGOAL. OR IS IT?🤨 ---->