6.11 EXPLOITING FULL-DUPLEX KEY REUSE

EXERCISE 6.11 EXPLOITING FULL-DUPLEX KEY REUSE

In previous exercises, you XORed some data together to see if you could still find patterns, but you didn’t actually XOR the two cipher streams together. Imagine if Alice and Bob used your ECDH exchange and derived the same key for full-duplex communication. Use the same key to encrypt some documents together for Alice to send to Bob and for Bob to send to Alice. XOR the cipher streams together and validate the result is the XOR of the plaintext. See if you can figure out any patterns from the XORed data.

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See Exercise 3.8 & 3.9.