Bidirectional Authentication via Trusted Third Party

The patent introduces a trusted third party (TTP) as an intermediary that manages public key distribution and verification. The TTP signs authentication tokens containing public keys, allowing entities to obtain validated public keys during the authentication process rather than requiring pre-established key pairs. This mediator resolves the contradiction by enabling ease of operation (no pre-shared keys needed) while maintaining reliability (TTP-signed tokens ensure key validity).

The trusted third party performs preliminary actions by pre-signing authentication tokens that contain public keys and validity information. These pre-prepared tokens are distributed to entities, who can then use them during authentication without needing to establish key pairs beforehand. This preliminary key distribution by the TTP enables entities to operate easily while ensuring key reliability through advance cryptographic signing.

The trusted third party acts as a mediator that performs the complex public key validation and signing operations externally. Entities only need to verify the TTP's signature on authentication tokens, which is a simplified operation compared to full public key validation. The TTP absorbs the complexity of key management and validation, allowing entities to maintain simple authentication processes while still achieving secure public key verification.

The patent uses authentication tokens that contain copies of public keys signed by the trusted third party. Instead of performing complex validation of actual public keys during authentication, entities verify the TTP's signature on these token copies. This copying approach simplifies the authentication process while maintaining security, as the signature verification on the token copy is computationally simpler than full public key validation.

The patent merges public key distribution and authentication into a single authentication token signed by the trusted third party. Instead of separate message exchanges for key distribution and verification, the TTP combines these functions into one signed token that entities can validate in a single step. This merging reduces the number of message passings required while maintaining authentication reliability through the TTP's cryptographic signature.

The trusted third party performs preliminary signing of authentication tokens that contain public keys and validity information. These pre-signed tokens are distributed to entities, who can then use them directly during authentication without requiring additional verification message exchanges. This preliminary action by the TTP consolidates multiple verification steps into a single token validation, improving communication efficiency while maintaining authentication reliability.