Anonymous event attestation
Methods, systems, and computer media provide attestation tokens that protect the integrity of communications transmitted from client devices, while at the same time avoiding the use of stable device identifiers that could be used to track client devices or their users. In one approach, client devices can receive batches of N device integrity elements from a device integrity computing system, each corresponding to a different public key. The N device elements can be signed by a device integrity computing system. The signing by the device integrity computing system can be signing with a blind signature scheme. Client devices can include throttlers imposing limits on the quantity of attestation tokens created by the client device.
1 . A method, comprising:
sending, by a client device and to a device integrity computing system, a request for N device integrity elements, the request including fraud detection signals for the client device and, for each of the N device integrity elements, public key data comprising at least one of (i) a respective public key for the device integrity element or (ii) a derivative of the respective public key for the device integrity element;
receiving, by the client device and from the device integrity computing system, the N device integrity elements, wherein each device integrity element comprises a digital signature generated based on a set of content comprising the public key data for the device integrity element, wherein each device integrity element comprises a blind signature of the public key data for the device integrity element generated using a blind signature scheme; and
sending, by the client device and to a recipient, a request comprising a device integrity token generated using a given device integrity element.
2 . The method of claim 1 , wherein Nis an integer that is greater than or equal to two.
3 . The method of claim 1 , wherein each device integrity element comprises a respective device integrity token comprising the set of content for the device integrity element, wherein the set of content for the device integrity element comprises (i) a timestamp indicating a time at which a verdict of trustworthiness was determined based on the fraud detection signals for the client device and (ii) the public key data for the device integrity element.
4 . The method of claim 1 , wherein the set of content for the device integrity element further comprises a verdict of trustworthiness determined based on the fraud detection signals for the client device.
5 . The method of claim 1 , wherein the public key data for each device integrity element comprises blinded public key data generated by blinding the device integrity element using the blind signature schemed.
6 . The method of claim 5 , further comprising unblinding the blind signature of the public key data for each device integrity element.
7 . The method of claim 6 , further comprising generating the device integrity token, wherein the device integrity token comprises the public key for the given device integrity element and the unblinded signature of the public key data for the given device integrity element.
8 . The method of claim 7 , wherein the device integrity token comprises a verdict of trustworthiness determined by the device integrity computing system based on the fraud detection signals for the client device.
9 . The method of claim 1 , wherein the blind signature of the public key data for each device integrity element is generated using a blind signing private key selected based on a verdict of trustworthiness determined by the device integrity computing system based on the fraud detection signals for the client device.
10 . The method of claim 1 , wherein the public key data for each device integrity element comprises the derivative of the public key for the device integrity element, and wherein the derivative of the public key for the device integrity element comprises a blinded public key blinded using the blind signature scheme.
11 . The method of claim 10 , wherein the derivative of the public key for the device integrity element comprises a blinded truncated cryptographic hash of the public key for the device integrity element.
12 . A system, comprising:
a client device comprising one or more processors; and
one or more memories having stored thereon computer readable instructions that, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
sending, by the client device and to a device integrity computing system, a request for N device integrity elements, the request including fraud detection signals for the client device and, for each of the N device integrity elements, public key data comprising at least one of (i) a respective public key for the device integrity element or (ii) a derivative of the respective public key for the device integrity element;
receiving, by the client device and from the device integrity computing system, the N device integrity elements, wherein each device integrity element comprises a digital signature generated based on a set of content comprising the public key data for the device integrity element, wherein each device integrity element comprises a blind signature of the public key data for the device integrity element generated using a blind signature scheme; and
sending, by the client device and to a recipient, a request comprising a device integrity token generated using a given device integrity element.
13 . The system of claim 12 , wherein N is an integer that is greater than or equal to two.
14 . The system of claim 12 , wherein each device integrity element comprises a respective device integrity token comprising the set of content for the device integrity element, wherein the set of content for the device integrity element comprises (i) a timestamp indicating a time at which a verdict of trustworthiness was determined based on the fraud detection signals for the client device and (ii) the public key data for the device integrity element.
15 . The system of claim 12 , wherein the set of content for the device integrity element further comprises a verdict of trustworthiness determined based on the fraud detection signals for the client device.
16 . The system of claim 12 , wherein the public key data for each device integrity element comprises blinded public key data generated by blinding the device integrity element using the blind signature schemed.
17 . The system of claim 16 , wherein the operations comprise unblinding the blind signature of the public key data for each device integrity element.
18 . The system of claim 17 , wherein the operations comprise generating the device integrity token, wherein the device integrity token comprises the public key for the given device integrity element and the unblinded signature of the public key data for the given device integrity element.
19 . The system of claim 18 , wherein the device integrity token comprises a verdict of trustworthiness determined by the device integrity computing system based on the fraud detection signals for the client device.
20 . A non-transitory computer readable medium storing instructions that upon execution by a client device cause the client device to perform operations comprising:
sending, by the client device and to a device integrity computing system, a request for N device integrity elements, the request including fraud detection signals for the client device and, for each of the N device integrity elements, public key data comprising at least one of (i) a respective public key for the device integrity element or (ii) a derivative of the respective public key for the device integrity element;
receiving, by the client device and from the device integrity computing system, the N device integrity elements, wherein each device integrity element comprises a digital signature generated based on a set of content comprising the public key data for the device integrity element, wherein each device integrity element comprises a blind signature of the public key data for the device integrity element generated using a blind signature scheme; and
sending, by the client device and to a recipient, a request comprising a device integrity token generated using a given device integrity element.