"Codebook, codebook..."
Yan Luo was rummaging through the house, trying to find the codebook left by his parents.
It's been almost nine years since his parents passed away, and many things in the house have changed places. Yan Luo couldn't remember where he had placed the codebook before.
After searching almost the entire house, Yan Luo finally found the codebook in a miscellaneous box on top of the wardrobe.
As he flipped through the paper codebook, Yan Luo simultaneously deciphered the email content.
It was an exhausting task; Yan Luo spent a full seven hours translating the email content into readable text.
Thankfully, Yan Luo became familiar with the ciphertext's pattern, or it could have taken even longer.
