Abstract: Techniques are disclosed relating to secure message exchanges. In some embodiments, a first computing device generates an account key associated with a user account shared by a plurality of computing devices. The first computing device signs a public key of the first computing device with the generated account key to produce a digital signature and sends the public key and the digital signature to a first server system for distributing the public key to a second computing device attempting to send an encrypted message to the first computing device. The first computing device sends the account key to an external storage external usable by others of the plurality of computing devices to obtain the account key and use the account key to sign public keys of the other computing devices. The first computing device receives, from the second computing device, the encrypted message encrypted using the public key.

Abstract: Some embodiments of the subject technology provide a novel system for synchronizing content items among a group of peer devices. The content synchronizing system of some embodiments includes the group of peer devices and a set of one or more synchronizing servers communicatively connected with the peer devices through one or more networks. In some embodiments, the synchronizing system uses a star architecture, in which each peer device offloads its synchronization operations to the synchronizing server set. Without establishing a peer-to-peer communication with any other peer device, the particular peer device in these embodiments supplies an encrypted content item set along with the N?1 encryptions of a content key used to encrypt the content item set to the synchronizing server set so that this server set can distribute the encrypted content item set and an encrypted content key to each of the N?1 peer devices.

Abstract: This Application sets forth techniques for establishing a custodial relationship between a user device and a custodian device for recovering access to a user account and/or to encrypted user data with assistance provided by the custodian device to effect access recovery. A server of a cloud network service provides an anonymous identifier to associate with the custodian device and an account recovery key to store at the custodian device. Identity of an account of the cloud network service associated with the custodian device can be hidden from the server. The user device generates a data recovery key and provides a first portion of the data recovery key to the custodian device and a second portion of the data recovery key to the server. Integrity of the stored account recovery key and portions of the data recovery key are checked regularly by the custodian device and the user device.

Abstract: Some embodiments of the subject technology provide a novel system for synchronizing content items among a group of peer devices. The content synchronizing system of some embodiments includes the group of peer devices and a set of one or more synchronizing servers communicatively connected with the peer devices through one or more networks. In some embodiments, the synchronizing system uses a star architecture, in which each peer device offloads its synchronization operations to the synchronizing server set. Without establishing a peer-to-peer communication with any other peer device, the particular peer device in these embodiments supplies an encrypted content item set along with the N?1 encryptions of a content key used to encrypt the content item set to the synchronizing server set so that this server set can distribute the encrypted content item set and an encrypted content key to each of the N?1 peer devices.

Abstract: One embodiment provides a system that implements a 1-bit protocol for differential privacy for a set of client devices that transmit information to a server. Implementations may leverage specialized instruction sets or engines built into the hardware or firmware of a client device to improve the efficiency of the protocol. For example, a client device may utilize these cryptographic functions to randomize information sent to the server. In one embodiment, the client device may use cryptographic functions such as hashes including SHA or block ciphers including AES to provide an efficient mechanism for implementing differential privacy.

Abstract: Some embodiments of the subject technology provide a novel system for synchronizing content items among a group of peer devices. The content synchronizing system of some embodiments includes the group of peer devices and a set of one or more synchronizing servers communicatively connected with the peer devices through one or more networks. In some embodiments, the synchronizing system uses a star architecture, in which each peer device offloads its synchronization operations to the synchronizing server set. Without establishing a peer-to-peer communication with any other peer device, the particular peer device in these embodiments supplies an encrypted content item set along with the N?1 encryptions of a content key used to encrypt the content item set to the synchronizing server set so that this server set can distribute the encrypted content item set and an encrypted content key to each of the N?1 peer devices.

Abstract: Techniques are disclosed relating to secure message exchanges. In some embodiments, a first computing device generates an account key associated with a user account shared by a plurality of computing devices. The first computing device signs a public key of the first computing device with the generated account key to produce a digital signature and sends the public key and the digital signature to a first server system for distributing the public key to a second computing device attempting to send an encrypted message to the first computing device. The first computing device sends the account key to an external storage external usable by others of the plurality of computing devices to obtain the account key and use the account key to sign public keys of the other computing devices. The first computing device receives, from the second computing device, the encrypted message encrypted using the public key.

Abstract: One embodiment provides a system that implements a 1-bit protocol for differential privacy for a set of client devices that transmit information to a server. Implementations may leverage specialized instruction sets or engines built into the hardware or firmware of a client device to improve the efficiency of the protocol. For example, a client device may utilize these cryptographic functions to randomize information sent to the server. In one embodiment, the client device may use cryptographic functions such as hashes including SHA or block ciphers including AES to provide an efficient mechanism for implementing differential privacy.

Abstract: One embodiment provides a system that implements a 1-bit protocol for differential privacy for a set of client devices that transmit information to a server. Implementations may leverage specialized instruction sets or engines built into the hardware or firmware of a client device to improve the efficiency of the protocol. For example, a client device may utilize these cryptographic functions to randomize information sent to the server. In one embodiment, the client device may use cryptographic functions such as hashes including SHA or block ciphers including AES to provide an efficient mechanism for implementing differential privacy.

Abstract: The subject technology may be implemented by a device that includes at least one processor configured to encrypt a data object based at least in part on an encryption key. The at least one processor may be further configured to sign the encrypted data object with a private key and transmit the signed encrypted data object to a server for retrieval by another device. The at least one processor may be further configured to generate a sharing object corresponding to the data object, wherein the sharing object includes an encryption key and a public key that corresponds to the private key. The at least one processor may be further configured to encrypt the sharing object using a key of the other device and transmit, over a secure channel, the encrypted sharing object to the other device for subsequent retrieval and verification of the signed data object from the server.

Abstract: One embodiment provides a system that implements a 1-bit protocol for differential privacy for a set of client devices that transmit information to a server. Implementations may leverage specialized instruction sets or engines built into the hardware or firmware of a client device to improve the efficiency of the protocol. For example, a client device may utilize these cryptographic functions to randomize information sent to the server. In one embodiment, the client device may use cryptographic functions such as hashes including SHA or block ciphers including AES to provide an efficient mechanism for implementing differential privacy.

Abstract: The system described may implement a 1-bit protocol for differential privacy for a set of client devices that transmit information to a server. Implementations of the system may leverage specialized instruction sets or engines built into the hardware or firmware of a client device to improve the efficiency of the protocol. For example, a client device may utilize these cryptographic functions to randomize information sent to the server. In one embodiment, the client device may use cryptographic functions such as hashes including SHA or block ciphers including AES. Accordingly, the system provides an efficient mechanism for implementing differential privacy.

Abstract: Some embodiments of the subject technology provide a novel system for synchronizing content items among a group of peer devices. The content synchronizing system of some embodiments includes the group of peer devices and a set of one or more synchronizing servers communicatively connected with the peer devices through one or more networks. In some embodiments, the synchronizing system uses a star architecture, in which each peer device offloads its synchronization operations to the synchronizing server set. Without establishing a peer-to-peer communication with any other peer device, the particular peer device in these embodiments supplies an encrypted content item set along with the N?1 encryptions of a content key used to encrypt the content item set to the synchronizing server set so that this server set can distribute the encrypted content item set and an encrypted content key to each of the N?1 peer devices.

Abstract: Some embodiments of the subject technology provide a novel system for synchronizing content items among a group of peer devices. The content synchronizing system of some embodiments includes the group of peer devices and a set of one or more synchronizing servers communicatively connected with the peer devices through one or more networks. In some embodiments, the synchronizing system uses a star architecture, in which each peer device offloads its synchronization operations to the synchronizing server set. Without establishing a peer-to-peer communication with any other peer device, the particular peer device in these embodiments supplies an encrypted content item set along with the N?1 encryptions of a content key used to encrypt the content item set to the synchronizing server set so that this server set can distribute the encrypted content item set and an encrypted content key to each of the N?1 peer devices.

Abstract: Some embodiments of the subject technology provide a novel system for synchronizing content items among a group of peer devices. The content synchronizing system of some embodiments includes the group of peer devices and a set of one or more synchronizing servers communicatively connected with the peer devices through one or more networks. In some embodiments, the synchronizing system uses a star architecture, in which each peer device offloads its synchronization operations to the synchronizing server set. Without establishing a peer-to-peer communication with any other peer device, the particular peer device in these embodiments supplies an encrypted content item set along with the N?1 encryptions of a content key used to encrypt the content item set to the synchronizing server set so that this server set can distribute the encrypted content item set and an encrypted content key to each of the N?1 peer devices.

Abstract: The system described may implement a 1-bit protocol for differential privacy for a set of client devices that transmit information to a server. Implementations of the system may leverage specialized instruction sets or engines built into the hardware or firmware of a client device to improve the efficiency of the protocol. For example, a client device may utilize these cryptographic functions to randomize information sent to the server. In one embodiment, the client device may use cryptographic functions such as hashes including SHA or block ciphers including AES. Accordingly, the system provides an efficient mechanism for implementing differential privacy.