Question

Assume that you are able to do an exhaustive search for the key to an encrypted message at the rate of 100 Million trials per second. How long in (days or years) would it take for you to find the key to a code that used a 112-­‐‑bit key on average? What encryption algorithm might have been used by the encryption system? (Give the name of an encryption algorithm that uses 112-­‐‑bit-­‐‑key.)

Answer 1

Answer:

Following are the solution to this question:

Explanation:

In point 1:

Trials frequency $= \frac{100 \ million }{second}$

calculating the main length of cryptography = 112 bit

$\to 100\ Million = 1 \times 10^8$

calculating the second year value:

$\to 365 \times 24 \times 60 \times 60 =3153600$

                                  $=3.15 \times 10^7 \ seconds$

Currently, in average , at least half the possible sleeves is being used to verify the encryption process:  $2^{111} \ keys$

$\to \frac{2^{111} \time3s 10^6}{3.15 \times 10^7}\approx 8.22 \times 10^{20} \ years$

the total time value will be $8.22 \times 10^{20} \ years$

In point 2:

In cryptography, the common name is Triple DES (3DES), which would be the symmetric-key encrypted communication algorithm (TDEAor Triple DEA), which adds 3 times per block size only with the cryptographic method Data Encryption Standard ( DES).  

Algorithm:-

The key package involves four DES keys, K1, K2, and K3, each 56-bit (except parity bits), Triple DES includes. Its encoding algorithm is::  

$ciphertext = EK3(DK2(EK1(plaintext)))$

I.e. K1, DES encrypt, K2 decrypt, then K3 encrypt DES.  

The reverse is the decryption:  

$plaintext = DK1(EK2(DK3(ciphertext)))$

I.e. decrypt by K3, crypt by K2, decrypt by K1.  

Every three-bit authentication encrypts a 64-bit block.

Its middle procedure in each situation it's the reverse of the first operation. It improves the strength of the key second option algorithm which offers DES native support with key option 3.