Implementation of a butterfly key expansion scheme

A registration authority module configured to implement a butterfly key expansion scheme, the registration authority module comprising:

• a first transmission module to receive a public caterpillar signing key of a private/public caterpillar signing key pair and a first pseudorandom function from a requesting device;
• an expansion module to expand the public caterpillar signing key into public cocoon signing keys using the first pseudorandom function;
• a generator module to generate certificate signing requests based on the public cocoon signing keys;
• a second transmission module to send the certificate signing requests to a certificate authority module and to receive unencrypted signed pseudonym certificates from the certificate authority module;
• and
• an encryption module to encrypt the unencrypted signed pseudonym certificates to generate response packages for downloading by the requesting device,
• wherein the registration authority module and its constituent modules are comprised of software running on a processor.