In this illustration we see Alice at top left along with her mailbox. Blue arrows point rightward and downward from it.

A blue arrow points rightward from Alice's mailbox to the Signed Hash, and another points rightward from the Signed Hash to the encryption algorithm. To the right of the algorithm is Bob's public key, K (+/B);" a blue arrow points from the key to the algorithm. A blue arrow points downwards from the algorithm to the Fixed-Length Hash, and another points downward from the Fixed-Length Hash to a blue diamond labeled "Compare."

A blue arrow points downward from Alice's mailbox to the original long message from Bob, and another points downward from the long letter to a blue box labeled "Many-to-one hash function." A blue arrow points rightward from the many-to-one hash function to the Fixed-Length Hash, and another points rightward from the Fixed-Length Hash to the diamond labeled "Compare."