One way to solve the key distribution problem is to use a line from a book that both the sender and

the receiver possess. Typically, at least in spy novels, the first sentence of a book serves as the key.

The particular scheme discussed in this problem is from one of the best suspense novels involving

secret codes, Talking to Strange Men, by Ruth Rendell. Work this problem without consulting that

book!

Consider the following message:

SIDKHKDM AF HCRKIABIE SHIMC KD LFEAILA

This ciphertext was produced using the first sentence of The Other Side of Silence $($a book about the

spy Kim Philby$)$:

The snow lay thick on the steps and the snowflakes driven by the wind looked black in the headlights

of the cars.

Tip:

A $->$ T

B $->$ h

C $->$ e

D $->$ s

E $->$ n

Etc

Decode the message: SIDKHKDM AF HCRKIABIE SHIMC KD LFEAILA