Methods for authenticating potential members invited to join a group

A computer-readable medium containing instructions for performing a method for an inviter computing device to issue an invitation for an invitee computing device to join an ad hoc group, the inviter and an authenticator computing device being members of the group, the invitee not being a member of the group, in which the inviter shares a secret password with the invitee, the method comprising:

• generating a first private encryption key based upon the secret shared password;
• generating a first public encryption key associated with the first private encryption key;
• creating an invitation containing the first public encryption key;
• signing the invitation using a private encryption key of the inviter;
• and
• making the invitation accessible to the invitee and to the authenticator.

In a computing environment with an ad hoc group, an inviter computing device and an authenticator computing device being members of the group, an invitee computing device not being a member of the group, the inviter having issued an invitation to the invitee to join the group, a method for the authenticator to issue an authentication challenge to the invitee, the method comprising:

• accessing the invitation;
• checking the invitation for validity;
• and if the invitation is valid, then
• generating a second private encryption key;
• generating a second public encryption key associated with the second private encryption key;
• generating a shared challenge encryption key from a first public encryption key contained in the invitation and the second private encryption key;
• generating a challenge value;
• creating an authentication challenge containing the challenge value and the second public encryption key;
• and
• making the authentication challenge accessible to the invitee.

A computer-readable medium containing instructions for performing a method for an authenticator computing device to issue an authentication challenge to an invitee computing device, an inviter computing device and the authenticator being members of an ad hoc group, the invitee not being a member of the group, the inviter having issued an invitation to the invitee to join the group, the method comprising:

• accessing the invitation;
• checking the invitation for validity;
• and
• if the invitation is valid, then
• generating a second private encryption key;
• generating a second public encryption key associated with the second private encryption key;
• generating a shared challenge encryption key from a first public encryption key contained in the invitation and the second private encryption key;
• generating a challenge value;
• creating an authentication challenge containing the challenge value and the second public encryption key;
• and
• making the authentication challenge accessible to the invitee.

In a computing environment with an ad hoc group, an inviter computing device and an authenticator computing device being members of the group, an invitee computing device not being a member of the group, in which the inviter shares a secret password with the invitee, the inviter having issued an invitation to the invitee to join the group, the authenticator having issued an authentication challenge to the invitee, a method for the invitee to issue a response to the authentication challenge, the method comprising:

• accessing the authentication challenge;
• generating a first private encryption key based upon the secret shared password;
• generating a shared challenge encryption key based upon the generated first private encryption key and upon a second public encryption key contained in the authentication challenge;
• generating a challenge response value based upon a challenge value contained in the authentication challenge;
• creating an authentication challenge response containing the challenge response value;
• and
• making the authentication challenge response accessible to the authenticator.

A computer-readable medium containing instructions for performing a method for an invitee computing device to issue a response to an authentication challenge, an inviter computing device and an authenticator computing device being members of an ad hoc group, the invitee not being a member of the group, in which the inviter shares a secret password with the invitee, the inviter having issued an invitation to the invitee to join the group, the authenticator having issued the authentication challenge to the invitee, the method comprising:

• accessing the authentication challenge;
• generating a first private encryption key based upon the secret shared password;
• generating a shared challenge encryption key based upon the generated first private encryption key and upon a second public encryption key contained in the authentication challenge;
• generating a challenge response value based upon a challenge value contained in the authentication challenge;
• creating an authentication challenge response containing the challenge response value;
• and
• making the authentication challenge response accessible to the authenticator.