Method and apparatus for cryptographic key storage wherein key servers are authenticated by possession and secure distribution of stored keys

• US 20020126850A1
• Filed: 03/08/2002
• Published: 09/12/2002
• Est. Priority Date: 03/09/2001
• Status: Active Grant

• Current Assignee: CA, Inc. (d/b/a CA Technologies) (Broadcom, Inc.)
• Original Assignee: Arcot Systems, Inc. (Broadcom, Inc.)
• Inventors: Allen, Robert, Wang, John, Wu, Tom, Jerdonek, Robert A.
• Granted Patent: US 7,711,122 B2
• Time in Patent Office: Days
• US Class Current: 380/277
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB
• CPC Class Codes: H04L 9/3228 One-time or temporary data, i.e. information which is sent for every authentication or authorization, e.g. one-time-password, one-time-token or one-time-key

Abstract

A key management system includes secured data stored on a first system secured by a control key stored securely on a key server. The secured data is secured against attacks such as unauthorized use, modification or access, where authorization to access the secured data is determined by knowledge of an access private key of an access key pair. When an authorized user is to access the secured data, the first system generates a request to the key server, signed with the access private key, wherein the request is for a decryption control key and the request includes a one-time public key of a key pair generated by the first system for the request. The first system can decrypt the decryption control key from the response, using a one-time private key. The first system can then decrypt the secured data with the decryption control key remaining secured in transport.

Claims

1. A method of accessing encrypted data, wherein the encrypted data is stored on a first secured system and a key usable for decrypting the encrypted data is stored on a second secured system and wherein the first secured system maintains a private key of a first secured system key pair, the method comprising:

obtaining a one-time key pair at the first secured system;

generating a request for the key including at least a public key of the one-time key pair;

signing the request with a private key of the first secured system;

sending the request to the second secured system;

responding to the request with a response, wherein the response includes at least the key requested by the first secured system, encrypted using the one-time public key provided in the request;

decrypting at least a part of the response using the one-time private key, so as to obtain the key; and

using at least the key provided as part of the response to decrypt the encrypted data.

2. The method of claim 1, wherein the first secured system is a key server client and second secured system is a key server.

3. The method of claim 1, wherein the second secured system is a key server serving a plurality of first secured systems.

4. The method of claim 1, wherein obtaining the one-time key pair at the first secured system comprises generating one-time key pair at the first secured system.

5. The method of claim 1, wherein the encrypted data comprises a plurality of private keys.

6. A secured system on which encrypted data is maintained and decryptable using a key stored on a remote system, the secured system comprising:

storage for a private key of a secured system key pair;

logic for generating or obtaining a one-time key pair;

logic for generating a request for the key including at least a public key of the one-time key pair;

logic for signing the request with the private key of the secured system key pair;

logic for processing a response from the remote system to the request, including logic to obtain the key from the request using the private key of the one-time key pair; and

a decryptor that decrypts the encrypted data using key provided by the remote system, whereby the remote system is authenticated based on whether the key provided by the remote system results in a correct decryption of the encrypted data.

7. A secured key server, wherein keys for a plurality of key clients are maintained, the secured key server comprising:

a database of keys, wherein each key is associated with a key client;

a communications module for receiving key requests that include one-time public keys and that are signed by a key client;

logic for authenticating the key client based on a public key of the key client;

logic for encrypting a response that includes the requested key and that is encrypted using the one-time public key; and

logic for sending the response to the requesting key client.