Secure session capability using public-key cryptography without access to the private key

摘要

A server establishes a secure session with a client device where a private key used in the handshake when establishing the secure session is stored in a different server. During the handshake procedure, the server receives a premaster secret that has been encrypted using a public key bound with a domain for which the client device is attempting to establish a secure session with. The server transmits the encrypted premaster secret to another server for decryption. The server receives the decrypted premaster secret and continues with the handshake procedure including generating a master secret from the decrypted premaster secret and generating one or more session keys that are used in the secure session for encrypting and decrypting communication between the client device and the server.

主权项

1. A method in a first server for establishing a secure session with a client device where a private key used for the secure session is stored in a second server, the method comprising the first server performing the following:
receiving a message from the client device that initiates a procedure to establish a secure session between the client device and the first server; transmitting a digital certificate to the client device that includes a public key; generating a set of cryptographic parameters; transmitting, to the second server, a message that includes the set of cryptographic parameters, wherein the second server has a private key that corresponds to the public key; receiving from the second server, a message that includes the set of cryptographic parameters that have been signed using the private key; transmitting, to the client device, the set of cryptographic parameters that have been signed using the private key; receiving, from the client device, a value generated by the client device based in part on the set of cryptographic parameters; generating, using the received value and at least some of the set of cryptographic parameters, a premaster secret; generating a master secret using the premaster secret; and generating, using the generated master secret, a set of one or more session keys to be used in the secure session for encrypting and decrypting communication between the client device and the first server.