Patent ID: 8577039

Claim:
A cryptographic communication apparatus for conducting a key exchange procedure with another cryptographic communication apparatus that shares a password with the cryptographic communication apparatus, the cryptographic communication apparatus comprising: a random number generator that generates a first random number and a second random number; a first encryption unit that encrypts information that is based on the first random number by the aid of a public key of the another cryptographic communication apparatus; a second encryption unit that encrypts the information that is based on the first random number encrypted by the first encryption unit, by the aid of the password; a third encryption unit that encrypts information that is based on the second random number by the aid of the first random number; and a transmitter that transmits a first signal and a second signal to the another cryptographic communication apparatus, the first signal including the information that is based on the first random number encrypted by the second encryption unit, and the second signal including the information that is based on the second random number encrypted by the third encryption unit.