Encrypted Message Authentication by Firewalls

Firewalls typically filter network traffic at several different layers. At application layer, filtering is based on various security relevant information encapsulated into protocol messages. The major obstacle for efficient verification of authenticity of messages at application layer is the difficulty of verifying digital signatures without disclosure of content protected by encryption. This is due to a traditional paradigm of generating a digital signature of a message and then encrypting the signature together with the message to preserve confidentiality, integrity, non-repudiation and authenticity. To overcome this limitation, a scheme shall be proposed for enabling signature verification without disclosing the content of messages. To provide maximum efficiency, the scheme is based on digital signcryption.