Key management and dynamic perfect forward secrecy
An indication is received from a server that a first pool of public keys should be transmitted to a server. At least one public-private keypair is generated in response to the received indication. The public key portion of the generated keypair is transmitted to the server. A subsequent indication is received from the server that an additional public key should be transmitted to the server.
1. A system, comprising: an interface configured to:
receive a pool of public keys from a first device, wherein the pool has a first pool size that reflects a target number of keys to be included in the pool;
a processor configured to:
designate one of the received public keys included in the pool of public keys as a reserve key; and
select a public key from the pool of public keys for use in conjunction with encrypting a communication to the first device, wherein the selecting includes preferentially selecting a public key that is not designated as a reserve key when at least one such key is present in the pool in addition to the reserve key, and
select the reserve key for use in conjunction with encrypting the communication when the reserve key is the only key remaining in the pool without deleting the reserve key from the pool until the pool is replenished; and
a memory coupled to the processor and configured to provide the processor with instructions.
2. The system of claim 1 wherein the processor is further configured to delete the selected public key from the pool.
3. The system of claim 1 wherein the processor is further configured to transmit the selected public key to a second device.
4. The system of claim 1 wherein the first device is configured to generate a plurality of public-private keypairs, and wherein the first device is configured to retain the private keys included in the generated keypairs, and transmit the public keys as the pool.
5. The system of claim 1 wherein the processor is further configured to determine that the number of keys currently in the pool is below a threshold and to instruct the first device to transmit additional public keys to replenish the pool.
6. The system of claim 1 wherein the processor is further configured to determine whether the reserve key has been selected and, in response to a determination that the reserve key has been selected, set a flag indicating that the first device should be instructed to generate additional keys.
7. The system of claim 6 wherein the processor is further configured to delete the reserve key and to designate one of the additional keys as a new reserve key.
8. The system of claim 6 wherein the processor is further configured to increase the first pool size to a second pool size.
9. The system of claim 1 wherein the processor is further configured to increase the first pool size to a second pool size.
10. A method, comprising:
receiving a pool of public keys from a first device, wherein the pool has a first pool size that reflects a target number of keys to be included in the pool;
designating one of the received public keys included in the pool of keys as a reserve key; and
selecting a public key from the pool of received public keys for use in conjunction with encrypting a communication to the first device, wherein the selecting includes preferentially selecting a public key that is not designated as a reserve key, if at least one such key is present in the pool in addition to the reserve key; and
selecting the reserve key for use in conjunction with encrypting the communication when the reserve key is the only key remaining in the pool without deleting the reserve key from the pool until the pool is replenished.
11. The method of claim 10 further comprising deleting the selected public key from the pool.
12. The method of claim 10 further comprising transmitting the selected public key to a second device.
13. The method of claim 10 wherein the first device is configured to generate a plurality of public-private keypairs, and wherein the first device is configured to retain the private keys included in the generated keypairs, and transmit the public keys as the pool.
14. The method of claim 10 further comprising determining that the number of keys currently in the pool is below a threshold and instructing the first device to transmit additional public keys to replenish the pool.
15. The method of claim 10 further comprising determining whether the reserve key has been selected and, in response to a determination that the reserve key has been selected, setting a flag indicating that the first device should be instructed to generate additional keys.
16. The method of claim 15 further comprising deleting the reserve key and designating one of the additional keys as a new reserve key.
17. The method of claim 15 further comprising increasing the first pool size to a second pool size.
18. The method of claim 10 further comprising increasing the first pool size to a second pool size.
19. A computer program product, the computer program product being embodied in a non-transitory tangible computer readable storage medium and comprising computer instructions for:
receiving a pool, having a first pool size, of public keys from a first device, wherein the pool size reflects a target number of keys to be included in the pool;
designating one of the received public keys included in the pool of keys as a reserve key;
selecting a public key from the pool of received public keys for use in conjunction with encrypting a communication to the first device, wherein the selecting includes preferentially selecting a public key that is not designated as a reserve key, if at least one such key is present in the pool in addition to the reserve key, and
selecting the reserve key for use in conjunction with encrypting the communication when the reserve key is the only key remaining in the pool without deleting the reserve key from the pool until the pool is replenished.