This illustration is similar to the one in figure 8.7 in which we see Bob's correspondence to Alice. Here, Bob's letter (identified as "Message: m") reads:

Dear Alice:

Sorry I have been unable to write for so long. Since we...Bob

A blue arrow points rightward from the letter to a blue box labeled "Encryption algorithm." Below this box is a key, labeled "Bob's private key, K (-/B)." A blue arrow points upwards from the key to the blue box. A blue arrow points rightward from the encryption algorithm to a second version of the letter, now identified as "Signed message: K (-/B) (m)." It reads:

fadfg54986fgnzmcnv

T98734ngldskg02j

ser09tugkjdflg

...