If a match is found, the terminal (118) generates a random secret key, encrypts the secret key with the stored public key, and transmits the encrypted secret key.

A user secret key generation device (200) uses the master secret key, to generate a user secret key of a query issue device (300).

The first shared secret key may be used for verification of a second shared secret key.

The secret key can be erased.

A shared secret key calculation section (28) calculates a matrix MAB (MAB = S-kAMBnASkA) as a shared secret key.

private key data confidentiality

private key data confidentiality

Suppose Alice has a private key a, and Bob has a private key b.

reCAPTCHA private key: Enter the private key for your site’s reCAPTCHA account.

Generally the signors computer system has a private key d and a public key y derived from an element g and the private key d.