This cipher uses a common key for encryption and decryption which is kept secret and is known to only the sender and reciever of the message.

The following is the cipher text encrypted using the key “vigilance”

“hmkb xe bp xpmylly rxiiqto lt fgzzv”

This when decrypted reads

“meet me on tuesday evening at seven”

So the challenge is to decrypt the following text which has also been encrypted using the key “vigilance”

“opoa nicjim qy kllygh vtvplbrv gdxnmc aaf ava sioe oa pzeoa naeqp”

Best of Luck!

Abhijit