Systems and methods for preventing transmitted cryptographic parameters from compromising privacy

1. A method for secure cryptographic communication, comprising:

transmitting plain text information that can be used to reference a group key from a first device to a second device in a first transmission;

in the first device, using the group key to encrypt an input vector;

in the first device, transmitting the encrypted input vector in a second transmission;

in the first device, encrypting privacy-sensitive information using a device key, an encryption algorithm, and the input vector; and

in the first device, transmitting the encrypted privacy-sensitive information to the second device in a third transmission.

2. The method of claim 1 , wherein the group key is referenced by a tuple comprising privacy-insensitive information.

3. The method of claim 2 , wherein the privacy-insensitive information includes information related to an issuing authority and an expiration date.

4. An RFID device, comprising:

an antenna;

a memory configured to store information including a group key, information that can be used to reference the group key, an input vector, a device key and privacy-sensitive information; and

a processor coupled with the memory and the antenna, the processor configured to:

transmit the information in plain text that can be used to reference the group key stored in the memory via the antenna in a first transmission,

use the group key to encrypt an input vector,

transmit the encrypted input vector via the antenna in a second transmission,

encrypt the privacy-sensitive information stored in the memory using the device key, an encryption algorithm, and the input vector, and

transmit the encrypted privacy-sensitive information in a third transmission.

5. The RFID device of claim 4 , wherein the group key is referenced by a tuple comprising privacy-insensitive information.

6. The RFID device of claim 5 , wherein the privacy-insensitive information comprises information related to an issuing authority and an expiration date.

7. A communication system, comprising:

a first device comprising:

an antenna;

a memory configured to store information including a group key, information that can be used to reference the group key, an input vector, a device key and privacy-sensitive information, and

a processor coupled with the memory and the antenna, the processor configured to:

transmit in plain text the information that can be used to reference the group key stored in the memory via the antenna in a first transmission,

use the group key to encrypt an input vector,

transmit the encrypted input vector via the antenna in a second transmission,

encrypt the privacy-sensitive information stored in the memory using the device key, an encryption algorithm, and the input vector, and

transmit the encrypted privacy-sensitive information in a third transmission; and

a second device comprising:

an antenna, and

a processor coupled with the antenna, the processor configured to

receive the information that can be used to reference the group key in the first transmission via the antenna;

use the received information to reference the group key;

receive the encrypted input vector in the second transmission via the antenna;

receive the encrypted privacy-sensitive information in the third transmission via the antenna;

use the referenced group key to decrypt the input vector; and

use the decrypted input vector and the encryption algorithm to decrypt the privacy-sensitive information.

8. The system of claim 7 , wherein the group key is referenced by a tuple comprising privacy-insensitive information.

9. The system of claim 8 , wherein the privacy-insensitive information comprises information related to an issuing authority and an expiration date.