Hi there. Just need some quick help if thats ok. Im giong through some examples for a security subject im studying and have the following question:
Consider a simple symmetric encryption algorithm as follows:
1- Input text T and 64 bit key K
2- Divide T into 64 bit size blocks B1...Bn
3- Get first block B1 and perform bit-wise XOR with K to produce encrypted block E1
4- Repeat
a. Get next block Bi and perform bit-wise XOR with Ei-1 to produce encrypted block Ei
5- Until End of Text
(a) Is it a problem if the first block of input happens to be the same as the key? Explain why?
(b) Modify the algorithm to rectify the above problem.
I just need some help with the solutions. I can see that the problem will be that the output will produce all 0's for A.. but does this propose a problem when decrypting the message? Any problems in the key perhaps being worked out?
Any help appreciated thanks
Consider a simple symmetric encryption algorithm as follows:
1- Input text T and 64 bit key K
2- Divide T into 64 bit size blocks B1...Bn
3- Get first block B1 and perform bit-wise XOR with K to produce encrypted block E1
4- Repeat
a. Get next block Bi and perform bit-wise XOR with Ei-1 to produce encrypted block Ei
5- Until End of Text
(a) Is it a problem if the first block of input happens to be the same as the key? Explain why?
(b) Modify the algorithm to rectify the above problem.
I just need some help with the solutions. I can see that the problem will be that the output will produce all 0's for A.. but does this propose a problem when decrypting the message? Any problems in the key perhaps being worked out?
Any help appreciated thanks
