Crytography Work

A hash code of a given message is a code that is created out of the message in accordance with a certain set of rules or in accordance with a certain algorithm.

1. An-X-bit message size is used, where a Y-bit hash code is generated ( X>Y ). How many messages share the same hash code? Provide a brief explanation of your answer.

2. In a ten-character per message system a four-character hash code is being produced. How many messages will be sharing the same hash code?

3. The following enemy encrypted message has been intercepted:

YJR NP<NSTTF<RMY EO:: DYSTY YP<PTTPE

A sleeper of ours behind enemy lines sent a message that the enemy's encryption had to do with the QWERTY keyboard layout. Decrypt the message and save lives.

4. An Enigma http://enigmaco.de/enigma/enigma.html encrypted message was intercepted and reads as follows:

OTIBDHEMUOFGMFMHGKMGNDOEGIBBKXZEJWR

A sleeper of ours behind enemy lines sent a message that the enemy's encryption used Rotor1: Z and Rotor3: E . Decrypt the message.

5. An encryption algorithm turned

GOOD MORNING AMERICA into FNNC LNQMHMF ZLDQHJZ

Identify the encryption algorithm and express it in a mathematical form.

6. How many unique keys are required in a 10 user symmetric encryption system?

7. How many unique keys are required in a 10 user asymmetric encryption system?

8. What is the meaning of signing a document? Is encryption included?

9. A certain cryptography vendor was providing an encryption technology that was breakable within one hour. Considering the continuous increase in computer speed, the company decided to increase the size of the encryption key so that the time to break the encryption become more than 250 hours. What should be the minimum key size increase to meet this objective, considering that in this encryption technology, the increase of a single bit in the size of the encryption key doubles the amount of needed computations.

Tape

Encryption

T M O M O E E E O O U E S C R A M R M E C A E N O N U A H U W E R I S R O S I X R N T L O E L A O G C Y L T L M W Y O T B H B

A 31.5cm long tape was intercepted with an end-to-end message, as it appears on the left. A sleeper of ours behind enemy lines sent a message that the enemy was using the Spartan relay run rod method, and the rod radius was 0.250 inches. 10. The following ciphertext is a monoalphabetic cipher: ROXBOOG TOSOXUXUVG WGP NVTMOXXUGM, UX UE W HWTCOI XLWX W GOB XLVDMLX OCOT EXTDMMIOE UGXV OAUEXOGQO. HWEVG QVVIOZ Decrypt this message, and briefly describe your cryptanalysis methodology. http://crypto.interactive-maths.com/monoalphabetic-substitution-ciphers.html