System and method for cryptographic key fragments management
A system, a method and a computer program product and a system, for Key Fragment Management (KFM). The KFM system comprises a plurality of KFM instances and a client device. At least two KFM instances are executed on execution platforms of two different service providers. Each KFM instance retains a root key fragment. The client device is configured to perform a cryptographic process relating to a data item using a data-specific key. Each KFM instance is configured to generate a data-specific key fragment based on a data identifier of the data item and based on the root key fragment in response to the client device requesting to generate the data-specific key for the data item. The data-specific key is generated based on a plurality of data-specific key fragments generated by the each KFM instances.
1. A method comprising:
obtaining a data identifier of a data item;
transmitting the data identifier to a plurality of Key Fragment Management (KFM) instances, wherein each KFM instance retains a root key fragment, wherein each KFM instance is configured to generate a data-specific key fragment by:
deriving, using the data identifier and the root key fragment, a pseudo-identifier, whereby obtaining a plurality of pseudo-identifiers from the plurality of KFM instances; and
deriving, using the pseudo-identifier and the root key fragment, the data-specific key fragment;
obtaining from the plurality of KFM instances, a plurality of data-specific key fragments;
generating a data-specific key based on the plurality of data-specific key fragments;
performing a cryptographic process, wherein the cryptographic process is an encryption of the data item using the data-specific key to provide an encrypted data item; and
storing the encrypted data item and storing the plurality of pseudo-identifiers in a manner allowing retrieval thereof for the encrypted data item.
2. The method of claim 1 , wherein said obtaining the data identifier comprises generating a non-deterministic data identifier.
3. The method of claim 1 , wherein at least two KFM instance are provided by two different service providers.
4. The method of claim 1 further comprises:
obtaining, in a local environment, a user key fragment,
wherein said generating the data-specific key is performed in the local environment and based on the plurality of data-specific key fragments and based on the user key fragment.
5. The method of claim 1 , wherein said obtaining the data identifier comprises applying a hash function on the data item.
6. The method of claim 1 , wherein each KFM instance is configured to generate at least a portion of a respective root key fragment independently.
7. The method of claim 1 , wherein each KFM instance is configured to generate a respective root key fragment using a random function.
8. The method of claim 1 , wherein a root key that is an aggregation of the root key fragments is never assembled.
9. The method of claim 1 ,
wherein each root key fragment comprises a static key fragment and an ephemeral key fragment, wherein a root key is an aggregation of the static key fragments and ephemeral key fragments;
wherein the method further comprises updating at least a portion of the ephemeral key fragments of the KFM instances without modifying the root key.
10. A method comprising:
obtaining a data identifier of a data item;
transmitting the data identifier to a plurality of Key Fragment Management (KFM) instances, wherein each KFM instance retains a root key fragment, wherein each KFM instance is configured to generate a data-specific key fragment by:
deriving, using the data identifier and the root key fragment, a pseudo-identifier, whereby obtaining a plurality of pseudo-identifiers from the plurality of KFM instances; and
deriving, using the pseudo-identifier and the root key fragment, the data-specific key fragment;
obtaining from the plurality of KFM instances, a plurality of data-specific key fragments;
generating a data-specific key based on the plurality of data-specific key fragments;
performing a cryptographic process, wherein the cryptographic process is a decryption of an encrypted data item using the data-specific key to obtain the data item;
wherein said obtaining the data identifier comprises retrieving the plurality of pseudo-identifiers for the encrypted data item; and
wherein said transmitting comprises transmitting the plurality of pseudo-identifiers to the plurality of KFM instances, wherein each KFM instance is configured to generate the data-specific key fragment based on the pseudo-identifier and based on the root key fragment using a single derivation process.
11. A computer program product comprising a non-transitory computer readable storage medium retaining program instructions, which program instructions when read by a processor, cause the processor to perform a method comprising:
obtaining a data identifier of a data item;
transmitting the data identifier to a plurality of Key Fragment Management (KFM) instances, wherein each KFM instance retains a root key fragment, wherein each KFM instance is configured to generate a data-specific key fragment by:
deriving, using the data identifier and the root key fragment, a pseudo-identifier, whereby obtaining a plurality of pseudo-identifiers from the plurality of KFM instances; and
deriving, using the pseudo-identifier and the root key fragment, the data-specific key fragment
obtaining from the plurality of KFM instances, a plurality of data-specific key fragments;
generating a data-specific key based on the plurality of data-specific key fragments; and
performing a cryptographic process relating to the data item using the data-specific key, wherein the cryptographic process is an encryption of the data item using the data-specific key to provide an encrypted data item, and
storing the encrypted data item and storing the plurality of pseudo-identifiers in a manner allowing retrieval thereof for the encrypted data item.
12. A Key Fragment Management (KFM) system comprising:
one or more processors and memory, wherein said one or more processors are configured to:
obtain a data identifier of a data item;
transmit the data identifier to a plurality of Key Fragment Management (KFM) instances, wherein each KFM instance retains a root key fragment, wherein each KFM instance is configured to generate a data-specific key fragment by:
deriving, using the data identifier and the root key fragment, a pseudo-identifier, whereby obtaining a plurality of pseudo-identifiers from the plurality of KFM instances; and
deriving, using the pseudo-identifier and the root key fragment, the data-specific key fragment;
obtain from the plurality of KFM instances, a plurality of data-specific key fragments;
generate a data-specific key based on the plurality of data-specific key fragments;
perform a cryptographic process, wherein the cryptographic process is an encryption of the data item using the data-specific key to provide an encrypted data item; and
store the encrypted data item and storing the plurality of pseudo-identifiers in a manner allowing retrieval thereof for the encrypted data item.
13. The KFM system of claim 12 , wherein comprising:
wherein said one or more processors are configured to:
decrypt the encrypted data item using the data-specific key to obtain the data item, wherein the decryption is performed after the plurality of pseudo-identifiers for the encrypted data item are retrieved and after the plurality of pseudo-identifiers are transmitted to the plurality of KFM instances, wherein each KFM instance is configured to generate the data-specific key fragment based on the pseudo-identifier and based on the root key fragment using a single derivation process.