BRIEF DESCRIPTION OF THE DRAWINGS
The present invention is described with the help of accompanying drawings:
FIG. 1 shows an example of symmetric cryptography known in the prior art.
FIG. 2 shows an example of asymmetric cryptography known in the prior art.
FIG. 3 shows a layer of a layered data processing system known in the prior art.
FIG. 4 shows a layered data processing system known in the prior art.
FIG. 5 shows the layered structure of a storage system known in the prior art.
FIG. 6 shows an overview of a storage system of the invention
FIG. 7 shows an embodiment of the invention of the process of transferring protected data between layered data processing systems.
FIG. 8 shows an embodiment of a layer in a layered data processing system of the invention.
FIG. 9 shows an embodiment of two layered data storage system interconnected with a data communication system.
FIG. 10 shows an embodiment of the process applying protection policies in a data processing layer.
FIG. 11 shows an embodiment of a recursive data processing layer.
DETAILED DESCRIPTION OF THE INVENTION
This invention is aimed at achieving faster and more efficient operations for moving data between layered data processing systems that use cryptographic protection internally. FIG. 6 shows an overview two data storage systems which are connected with each other through a trusted and an untrusted channel. Each of the data storage system is further connected to at least one trusted and at least one untrusted storage device. (The figure only shows one instance of the trusted and untrusted storage devices per data storage system). The data storage devices might be connected to further data storage devices not shown on the figure. As shown in FIG. 7, protected (i.e., encrypted or authenticated) data is transferred between data processing systems keeping the format of the protected data intact and adding protection attributes, such as encryption keys or message-authentication keys for a message-authentication code (MAC) separately. The invention is to enhance a layered data processing system to work with separate interfaces for data and protection attributes. More precisely, the invention enhances the interface of the layered data storage system by adding set of protection attributes (7.1), which express the cryptographic operations that were applied to the stored data at the time of storing it. Data that is modified in this way is called protected data. The protected data may have been encrypted with a symmetric cryptosystem or with an asymmetric cryptosystem. In this case, the protection attributes consist of the secret or of the public key that was applied to the data. Protected data may also be authenticated using a MAC or signed using a digital signature scheme. Here, the protection attributes include the secret MAC-key and the authentication tag or the digital signature and the signature private key. In this way it is possible to reconstruct the raw data from the protected data and the protection attributes such as message authentication code, encryption keys, digital signatures etc. Hence the protected data together with the protection attributes provide for a different representation of the data. Such cryptographically protected data can be represented as an abstract Crypto Container data type that separates between data and protection attributes. A crypto container consists of protection attributes and protected data. A protection attribute describes the cryptographic protection scheme that has been applied to the protected data in the container.
The protected data is then transferred to the second data processing system (7.2) in this form. The protection attributes are themselves not protected but exported and imported as they are (in cleartext). It must be ensured that the protection attributes are only exported in a trusted environment. Hence, if the environment consists of an untrusted data channel the transfer of protection attributes between data processing layers has to be done through a secure channel. Importing protected data is more efficient because it is not necessary to protect the data a second time. At the second system protection attributes alone are encrypted in the format of the second system (7.3). the unaltered data from the first system and the encrypted protection attributes are then stored on the second system (7.4)
FIG. 7 shows one layer of the enhanced data processing system. The layer now provides for a separation between protected data and protection attributes (PA) for the write input from above and for the read input from below, respectively. Likewise, the layer may output protected data separated from protection attributes for the write output to the lower layer and for the read output to the layer above.
Transmission of protected data between layered processing systems may involve a further layered data processing system that involves cryptographic protection. In this case, the cryptographic protection can be applied to the protection attributes, but may be skipped for the protected data, which is more efficient.
It should be noted that the said protected data and the said protection attributes together are not protected but provide for a different representation of the data. This is to allow reconstruction of the plain data from the protected data and the protection attributes.
The basic aim of the aforementioned representation of the data is to gain efficiency when transferring protected data between data processing systems with different protection schemes. The efficiency arises from the fact that the data to be exported from one data processing system to the target data processing system is not required to be decrypted at the first system and can be transferred in the original encrypted format along with the protection attributes.
The target data processing system does not need to encrypt the protected data again but can encrypt merely the protection attributes with a key owned by the target data processing system.
The advantage of this secure and efficient method for migration or transfer of data between data processing systems is that one can avoid going through the complicated decryption process before data migration between data processing systems.
FIG. 9 shows a preferred embodiment of this invention consisting of at least two data storage systems, at least two data communication systems, at least one trusted and one untrusted storage device. A user or an application of the data storage system 1 writes data to the data storage system. To illustrate this, three data messages A, B, C are shown; however, any arbitrary number of data messages can be written to the data storage system. The protection of the data messages at this point is dependent on the configuration of the system and might be given through existing means such as login password or a Kerberos ticket (J. Kohl and C. Neuman, The Kerberos Authentication Service, RFC 1510, September 1993). The write connector for protection attributes is therefore dashed. The data storage system applies protection attributes to the entering data A, B, and C according to the protection policy PP1, stores the protection attributes on one or more trusted storage devices and stores the data on one or more untrusted storage devices. The process of applying the protection policies is explained later in this document. When the data has to be transferred through data communication systems to second data storage system the data storage system 1 writes the protection attributes PAA, PAB, and PAC, and the protected data PAA(A), PAB(B), and PAC(C), as crypto containers CC1, CC2, and CC3 to the next layer.
Data communication systems 1 and 2 share the same crypto object attributes PAD which have been exchanged using any known key distribution protocol through a trusted channel. Upon receipt of one or more crypto containers the data communication system 1 may wrap several crypto containers into a single one or split crypto containers into two or more containers. It also may apply additional encryption based on the protection policy PP2. The actual start and end point of incoming crypto containers which go into a new outgoing crypto container CC4 depends on the functionality of the data communication system and is not further specified here. In the figure, the three crypto containers CC1-3 are wrapped into crypto container CC4, whereby the protection attributes are encrypted by the encryption attributes PAD. The data which is already sufficiently protected according to PP2, here PAA(A) and PAB(B), are not reencrypted. Only PAC(C) which is not sufficiently protected is encrypted using the protection attributes PAD. The new crypto container CC4 is then written to the next layer, residing in the data communication system 2. The data communication system 2 communicates with the data storage system 2 through a trusted environment. Therefore the crypto container CC4 can be unwrapped and no protection policies need to be applied to write the restored crypto container CC5 to the data storage system 2. Similar as above, the data storage system 2 may wrap or split crypto containers. In this embodiment the data storage system 2 illustrates a tape archival device which splits the crypto container CC5 into two different crypto containers CC6 and CC7. Here again, the data storage system may apply additional encryption based on the protection policy PP2 as it is shown for PAF(PAC(C)). For each crypto container the data is stored on a separate storage devices named tape devices whereas the crypto attributes PAE and PAF are stored on a trusted storage device. The read process is analogous to the write process and is not further explained here.
The process of applying protection policies in a data processing layer is shown in FIG. 10. A crypto container consisting of crypto attributes PAX and data PAX(X) is first checked whether the data PAX(X) is sufficiently protected according to the protection policies PPY of the data processing layer. If the data PAX(X) is not sufficiently protected the protection attributes PAY provided by the current layer have to be applied to the data to build the new data Y=PAY(PAX(X)). In a next step the protection attributes PAX of the crypto container are protected with the protection attributes of the data processing layer PAY. In case the data is already sufficiently protected, only the protection attributes PAX are protected with the protection attributes of the data processing layer PAY and the new data Y=PA(X) remains unchanged. Finally the new crypto container PAY(PAX),Y is ready for further processing by the data processing layer.
In another embodiment of the present invention one or more data processing layers may be merged into a single processing layer. FIG. 11 shows two data processing layer, a first one consisting of an encryption device and a second one of storage devices which are merged into one single data processing layer.
The above description related to specific embodiments of the invention and was described with the help of specific language for the purpose of promoting an understanding of the principles of the invention. It must nevertheless be understood that no limitation of the scope of the invention is thereby intended. The scope of the invention shall include such alterations and modifications in the embodiments and such further applications of the principles of the invention as would normally occur to one skilled in the art to which the invention relates.
Patent Application
20080098217
