# Two possible plaintext's using OTP decryption

I am using this cipher-text

c   = 04 10 12 00 01 08 67 0A 19 65 0F 03 0A 00


with two possible keys

k_1 = 45 44 46 41 42 43 47 4B 4D 45 4B 42 5D 4E


and

k_2 = 45 44 46 41 42 43 47 4B 4D 45 41 4C 45 4E


If I decrypt the cipher-text with k_1 I am getting 'ATTACK AT DAWN' and with k_2 'ATTACK AT NOON'. Which of the plaintexts is more likely to be the original plaintext and why?

• This is ill-formatted homework! You cannot get OTP keys! Anyway, What do you think about it? – kelalaka Nov 16 '19 at 23:04
• What I have learned is that the OTP is 'perfectly secure'. In my opinion I don't think there is a way to assume that one plaintext is more likely to be the original. – NimeQ Nov 16 '19 at 23:10
• Yes, As long as there is no additional information about the message, All keys are valid for OTP. Therefore, your two messages are valid. – kelalaka Nov 16 '19 at 23:12
• 'perfectly secure' Which is exactly what @kelalaka has said. That's why we use OTPs. And if you run the numbers, the message might say 'CONGLOBULATING'. – Paul Uszak Nov 16 '19 at 23:24

• That answer is invalid, because the lowercase k is a typo (perhaps intentional; in that case, it briefly fouled us). My bets are NOON, because ] :-) – fgrieu Dec 17 '19 at 10:21