Secured cloud data storage, distribution and restoration among multiple devices of a user

A secured server for sharing content stored on a database between a first electronic device of a user and a second electronic device of the user, different from the first device, wherein the secured server comprises:

• a network interface;
• a non-transitory computer-readable medium comprising instructions stored thereon;
• and
• a processor configured by the instructions to perform acts comprising:
• associating, in the non-transitory computer-readable medium, said content to a user account and to the first electronic device of the user, wherein the user account is a single user account to which the first and second electronic devices are associated,
• storing, in the non-transitory computer-readable medium, an association resulting from the act of associating said content to the user account and to the first electronic device of the user,
• storing the content in an encrypted form as a first-public-key encrypted content in the non-transitory computer-readable medium, said first-public-key encrypted content being encrypted with a public key of said first electronic device,
• associating, in the non-transitory computer-readable medium, said second electronic device with a second electronic device public key and a second electronic device private key,
• storing in the non-transitory computer-readable medium an association resulting from the act of associating said second electronic device with the second electronic device public key and the second electronic device private key,
• storing a first re-encryption key in the non-transitory computer-readable medium, said first re-encryption key being configured to re-encrypt the first-public-key encrypted content, said first re-encryption key being calculated by the processor using proxy re-encryption (PRE) technology, and further being calculated using a first electronic device private key associated with the first electronic device public key and using the second electronic device public key,
• determining association of the first-public-key encrypted content with the second electronic device,
• re-encrypting the first-public-key encrypted content using the first re-encryption key to generate a re-encrypted content,
• sending, using the network interface, the re-encrypted content to the second electronic device with a request asking the second electronic device to decrypt the re-encrypted content using the second electronic device private key, thereby generating a decrypted content, and to encrypt the decrypted content using the second electronic device public key, thereby generating a second-public-key encrypted content,
• receiving, using the network interface, from the second electronic device the second-public-key encrypted content that has been encrypted using the second electronic device public key, and
• associating the second-public-key encrypted content received from the second electronic device to the second electronic device and the user account,
• storing the second public-key encrypted content received from the second electronic device in association with said second electronic device and the user account in the non-transitory computer-readable medium.

A non-transitory storage medium comprising a computer program product stored thereon and executable by a processor in the form of a software agent including at least one software module setup to implement a method to share a content stored on a secured server, between a first electronic device of a user and a second electronic device of the user, different from the first device,

• wherein the at least one software module configures the secured sever to perform acts comprising:
• associating said content to a user account and to the first electronic device of the user, wherein the user account is a single user account to which the first and second electronic devices are associated,
• storing an association resulting from the act of associating said content to the user account and to the first electronic device of the user,
• storing the content in an encrypted form as a first-public-key encrypted content, said first-public-key encrypted content being encrypted with a public key of said first electronic device,
• associating said second electronic device with a second electronic device public key and a second electronic device private key,
• storing an association resulting from the act of associating said second electronic device with the second electronic device public key and the second electronic device private key,
• storing a first re-encryption key, said first re-encryption key being configured to re-encrypt the first-public-key encrypted content,
• said first re-encryption key being calculated using proxy re-encryption (PRE) technology, and further being calculated using a first electronic device private key associated with the first electronic device public key and using the second electronic device public key,
• determining association of the first-public-key encrypted content with the second electronic device,
• re-encrypting the first-public-key encrypted content using the first re-encryption key to generate a re-encrypted content, c) sending the re-encrypted content to the second electronic device with a request asking the second electronic device to decrypt the re-encrypted content using the second electronic device private key, thereby generating a decrypted content, and to encrypt the decrypted content using the second electronic device public key, thereby generating a second-public-key encrypted content,
• receiving from the second electronic device the second-public-key encrypted content that has been encrypted using the second electronic device public key,
• associating the second-public-key encrypted content received from the second electronic device to the second electronic device and the user account,
• storing the second public-key encrypted content received from the second electronic device in association with said second electronic device and the user account.