Question

Please only select ONE of the following multiple choices as the correct answer. In a sentence or two, justify your answer for my understanding. Thanks.

We consider the one-time pad with messages and keystreams both binary sequences. Suppose that the system is used erroneously, so that two messages have been encrypted using the same key. What information can an adversary that hears the two ciphertexts deduce about the plaintexts? От The adversary can deduce the frequency of 1s and Os in both plaintexts The adversary cannot gain any additional information The adversary can identify exactly in which bit positions the two messages differ

Answer 1

Answer:-

The on one occasion protection in the midst of mail and key-streams both double sequence. here the scheme is used incorrectly so that two mail have been encrypted by the similar type.

If the two mail have been encrypted using the similar type then the keystream use again in stream ciphers.

And here the once pads risk to bona fide systems has been not doing well since the past techniques have been relied on deduction terms and phrases which are emerge in one of the plaintext messages and so by making it easier.

we can say that the invader cannot do encrypting using the similar type.

The information is that they were both encrypted with the same key. And attacked by encrypting and uncovering the plain text by follow steps like.

By Guessing a word that might appear in one of the messages.

By Encoding the word from step 1 to a hex string.

By XOR the two cipher-text messages

By XOR the hex string from step 2 at each position of the XOR of the two cipher-texts from step 3.

When the result from step 4 is readable text we guess the English word and expand our crib search.

If the result is not readable text we try an XOR of the crib word at the next position.

So the random generated key and combining it with the plaintext to form the ciphertext. If it is used more than once then we could find out how the key and plaintext are being used to form the ciphertext then exploit this to deduce the plain text.