Encryption techniques for improved sharing and distribution of encrypted content

摘要

In an embodiment, content may be encrypted by a first device using a dual hash chain technique, where the first device maintains a forward hash chain and a second device maintains a backward hash chain, and content keys for encrypting content are derived using values of the forward and backward hash chains. The second device may not have knowledge of a seed used to generate the forward hash chain, and therefore may be unable to generate the content keys, reducing a likelihood that the encrypted content becomes compromised. Additionally, embodiments provide for techniques for using proxy re-encryption (PRE) to re-encrypt content, such that the encrypted content may be provided to and decrypted by a requesting device without knowledge of the forward and backward hash chains. Additionally, embodiments provide techniques for distributing encrypted content to a requesting device with fine-grained access control.

主权项

1. A method comprising:
generating, by a first device, a forward seed and a backward seed, wherein the forward seed and the backward seed are used to generate a forward hash chain and a backward hash chain, and wherein hash values derived from the forward hash chain and the backward hash chain are used to generate content keys for encrypting and decrypting content; encrypting, by the first device, the forward seed and the backward seed using proxy re-encryption to produce encrypted seed information; initiating, by the first device, transmission of the encrypted seed information and the backward seed to a second device, wherein the second device stores the backward seed and the encrypted seed information; and encrypting, by the first device, first content using a first content key to produce first encrypted content, wherein the first content key is generated based on a forward hash chain value associated with the forward hash chain and a backward hash chain value associated with the backward hash chain, and wherein the backward hash chain value is received from the second device.