Method to manage modification of encryption credentials

1. A method to manage modification of encryption credentials for an encryption server, said encryption server being configured to encrypt data uploaded by a user after provision of encryption credentials of the user that are associated with an encryption account, said encrypted data using a user encryption key stored in a cloud storage server,

said method comprising the initialization steps of, for the encryption server, authenticating the user to the encryption account using encryption credentials and binding the encryption account to a user's storage account in the cloud storage server through the following sub-steps:

for the storage server, authenticating the user to his/her storage account using storage credentials, issuing an initial access token based on an online authentication protocol and sending the initial access token to the encryption server, and

for the encryption server, encrypting the initial access token and the user encryption key using the encryption credentials and storing the encrypted initial access token and user encryption key for further use to decrypt the uploaded data under request of the user and provision of his/her encryption credentials, encrypting the user encryption key using an encryption server recovery master key and sending, for storage, the encrypted user encryption key to the storage server,

said method further comprising the following steps, when user triggers an encryption credentials reset,

for the storage server, authenticating the user to his/her storage account using storage credentials, issuing a new access token based on an online authentication protocol and sending the new access token to the encryption server, and

for the encryption server, using the new access token to retrieve the encrypted user encryption key from the storage server, decrypting the encrypted user encryption key using the encryption server recovery master key, requiring new encryption credentials to be input by the user, encrypting the new access token and the plain decrypted user encryption key using the new encryption credentials and storing them for further use to decrypt the uploaded data under request of the user and provision of his/her new encryption credentials.

2. The method according to claim 1 , wherein an encryption credential is a user name/password pair.

3. The method according to claim 2 , wherein the password is used to encrypt the initial access token and the user encryption key.

4. The method of claim 3 , wherein the password is used as an input to a key derivation function, and the resulting key is used to encrypt the initial access token and the user encryption key.

5. The method according to claim 1 , wherein the online authentication protocol is a three-steps OAuth handshake.

6. An encryption server adapted to manage modification of encryption credentials according to claim 1 , said encryption server being used to encrypt data uploaded by a user after provision of the user's encryption credentials associated with an encryption account, said encrypted data using a user encryption key stored in a cloud storage server, said encryption server including:

an authentication module to authenticate the user to the encryption account using encryption credentials,

an encryption/decryption module to encrypt/decrypt access tokens as provided by the storage server and the user encryption key using the encryption credentials, to encrypt/decrypt uploaded data using user encryption key, to encrypt/decrypt the user encryption key using an encryption server recovery master key before sending to the storage server and when the encrypted user encryption key is retrieved from storage device,

a memory to store access token and user encryption key encrypted using the encryption credentials, and

a link with a human machine interface for the user to input new encryption credentials.