Securing data in a dispersed storage network

• US 10,360,097 B2
• Filed: 08/29/2016
• Issued: 07/23/2019
• Est. Priority Date: 05/30/2013
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Resch, Jason K., Dhuse, Greg
• Primary Examiner(s): Colin, Carl G
• Assistant Examiner(s): Little, Vance M
• Application Number:
  US15/249,905
• Publication Number:
  US 20160371143A1
• Time in Patent Office: 1,058 Days
• CPC Class Codes: G06F 11/1004 to protect a block of data words, e.g. CRC or checksum G06F11/1076 takes precedence; security arrangements for protecting computers or computer systems against unauthorized activity G06F21/00
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 11/1096 Parity calculation or recalculation after configuration or reconfiguration of the system
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 21/80 in storage media based on magnetic or optical technology, e.g. disks with sectors preventing unauthorised reproduction or copying of disc-type recordable media G11B20/00
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: H04L 1/0042 Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 63/0457 wherein the sending and receiving network entities apply dynamic encryption, e.g. stream encryption cryptographic mechanisms or cryptographic arrangements for stream encryption H04L9/065
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 63/062 for key distribution, e.g. centrally by trusted party cryptographic mechanisms or cryptographic arrangements for key distribution involving a central third party H04L9/0819
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols

Abstract

A method includes receiving a retrieval request regarding an encoded key stream slice of a set of encoded key stream slices and an encoded and encrypted data slice of a set of encoded and encrypted data slices. The method further includes partially dispersed storage error decoding the encoded key stream slice to produce a partially decoded key stream vector. The method further includes partially dispersed storage error decoding the encoded and encrypted data slice to produce a partially decoded and encrypted data vector. The method further includes partially decrypting the partially decoded and encrypted data vector in accordance with the encryption function and based on the partially decoded key stream vector to produce a partially decrypted and decoded data vector. The method further includes sending the partially decrypted and encoded data vector to the requesting computing device.

Claims

1. A method for execution by a storage unit of a dispersed storage network (DSN), the method comprises:

receiving, from a requesting computing device of the DSN, a retrieval request regarding an encoded key stream slice of a set of encoded key stream slices and an encoded and encrypted data slice of a set of encoded and encrypted data slices, wherein a plurality of data elements of a data element set of a data object is encrypted using a plurality of keystream characters of a key stream and an encryption function to produce a plurality of encrypted data elements, wherein the plurality of encrypted data elements are arranged to produce an encrypted data element set, wherein the encrypted data element set is dispersed storage error encoded in accordance with dispersed data storage parameters to produce the set of encoded and encrypted data slices, wherein the set of encoded and encrypted data slices are stored in a set of storage units of the DSN, wherein the key stream is dispersed storage error encoded in accordance with the dispersed data storage parameters to produce the set of encoded key stream slices, wherein the set of encoded key stream slices are stored in the set of storage units, wherein the set of storage units includes the storage unit, and wherein the dispersed data storage parameters include a decode threshold number;

partially dispersed storage error decoding the encoded key stream slice to produce a partially decoded key stream vector that includes a plurality of partially decoded key stream vector blocks;

partially dispersed storage error decoding the encoded and encrypted data slice to produce a partially decoded and encrypted data vector that includes a plurality of partially decoded and encrypted data vector blocks;

partially decrypting the partially decoded and encrypted data vector based on a function in accordance with the encryption function and based on the partially decoded key stream vector to produce a partially decrypted and decoded data vector, wherein the function includes an exclusive OR that is performed on corresponding blocks of the plurality of partially decoded key stream vector blocks and the plurality of partially decoded and encrypted data vector blocks; and

sending the partially decrypted and decoded data vector to the requesting computing device, wherein the requesting computing device is without access to the key stream, and wherein the decode threshold number of partially decrypted and decoded data vectors are required to reconstruct the data element set.

2. The method of claim 1 further comprises:

converting an encryption key into the key stream.

3. The method of claim 1, wherein the partially dispersed storage error decoding the encoded and encrypted data slice to produce the partially decoded and encrypted data vector comprises:

obtaining a square matrix, wherein the square matrix is derived from an encoding matrix of the dispersed storage error encoding; and

generating the partially decoded and encrypted data vector based on the square matrix and the encoded and encrypted data slice.

4. A storage unit of a dispersed storage network (DSN), the storage unit comprises:

a network interface;

memory; and

a processing module operably coupled to the network interface and the memory, wherein the processing module is operable to;

receive, via the network interface and from a requesting computing device of the DSN, a retrieval request regarding an encoded key stream slice of a set of encoded key stream slices and an encoded and encrypted data slice of a set of encoded and encrypted data slices, wherein a plurality of data elements of a data element set of a data object is encrypted using a plurality of keystream characters of a key stream and an encryption function to produce a plurality of encrypted data elements, wherein the plurality of encrypted data elements are arranged to produce an encrypted data element set, wherein the encrypted data element set is dispersed storage error encoded in accordance with dispersed data storage parameters to produce the set of encoded and encrypted data slices, wherein the set of encoded and encrypted data slices are stored in a set of storage units of the DSN, wherein the key stream is dispersed storage error encoded in accordance with the dispersed data storage parameters to produce the set of encoded key stream slices, wherein the set of encoded key stream slices are stored in the set of storage units, wherein the set of storage units includes the storage unit, and wherein the dispersed data storage parameters include a decode threshold number;

partially dispersed storage error decode the encoded key stream slice to produce a partially decoded key stream vector that includes a plurality of partially decoded key stream vector blocks;

partially dispersed storage error decode the encoded and encrypted data slice to produce a partially decoded and encrypted data vector that includes a plurality of partially decoded and encrypted data vector blocks;

partially decrypt the partially decoded and encrypted data vector based on a function in accordance with the encryption function and based on the partially decoded key stream vector to produce a partially decrypted and decoded data vector, wherein the function includes an exclusive OR that is performed on corresponding blocks of the plurality of partially decoded key stream vector blocks and the plurality of partially decoded and encrypted data vector blocks; and

send the partially decrypted and decoded data vector to the requesting computing device, wherein the requesting computing device is without access to the key stream, and wherein the decode threshold number of partially decrypted and decoded data vectors are required to reconstruct the data element set.

5. The storage unit of claim 4, wherein the processing module is further operable to:

receive, via the network interface, the encoded key stream slice, wherein an encryption key is converted into the key stream.

6. The storage unit of claim 4, wherein the processing module is further operable to partially dispersed storage error decode the encoded and encrypted data slice to produce the partially decoded and encrypted data vector by:

obtaining a square matrix, wherein the square matrix is derived from an encoding matrix of the dispersed storage error encoding; and

generating the partially decoded and encrypted data vector based on the square matrix and the encoded and encrypted data slice.

7. A computer readable memory comprises:

a first memory element that stores operational instructions that, when executed by a first storage unit of a dispersed storage network (DSN), causes the first storage unit to;

receive, from a requesting computing device of the DSN, a first retrieval request regarding a first encoded key stream slice of a set of encoded key stream slices and a first encoded and encrypted data slice of a set of encoded and encrypted data slices, wherein a plurality of data elements of a data element set of a data object is encrypted using a plurality of keystream characters of a key stream and an encryption function to produce a plurality of encrypted data elements, wherein the plurality of encrypted data elements are arranged to produce an encrypted data element set, wherein the encrypted data element set is dispersed storage error encoded in accordance with dispersed data storage parameters to produce the set of encoded and encrypted data slices, wherein the set of encoded and encrypted data slices are stored in a set of storage units of the DSN, wherein the key stream is dispersed storage error encoded in accordance with the dispersed data storage parameters to produce the set of encoded key stream slices, wherein the set of encoded key stream slices are stored in the set of storage units, wherein the set of storage units includes the storage unit, and wherein the dispersed data storage parameters include a decode threshold number;

partially dispersed storage error decode the first encoded key stream slice to produce a first partially decoded key stream vector that includes a plurality of partially decoded key stream vector blocks;

partially dispersed storage error decode the first encoded and encrypted data slice to produce a first partially decoded and encrypted data vector that includes a plurality of partially decoded and encrypted data vector blocks;

partially decrypt the first partially decoded and encrypted data vector based on a function in accordance with the encryption function and based on the partially decoded key stream vector to produce a partially decrypted and decoded data vector, wherein the function includes an exclusive OR that is performed on corresponding blocks of the plurality of partially decoded key stream vector blocks and the plurality of partially decoded and encrypted data vector blocks; and

send the partially decrypted and decoded data vector to the requesting computing device, wherein the requesting computing device is without access to the key stream, and wherein the decode threshold number of partially decrypted and decoded data vectors are required to reconstruct the data element set; and

a second memory element that stores operational instructions that, when executed by a second storage unit of the DSN, causes the second storage unit to;

receive, from the requesting computing device of the DSN, a second retrieval request regarding a second encoded key stream slice of the set of encoded key stream slices and a second encoded and encrypted data slice of the set of encoded and encrypted data slices;

partially dispersed storage error decode the second encoded key stream slice to produce a second partially decoded key stream vector that includes a second plurality of partially decoded key stream vector blocks;

partially dispersed storage error decode the second encoded and encrypted data slice to produce a second partially decoded and encrypted data vector that includes a second plurality of partially decoded and encrypted data vector blocks;

partially decrypt the second partially decoded and encrypted data vector based on the function in accordance with the encryption function and based on the second partially decoded key stream vector to produce a second partially decrypted and decoded data vector, wherein the function includes the exclusive OR that is performed on corresponding blocks of the second plurality of partially decoded key stream vector blocks and the second plurality of partially decoded and encrypted data vector blocks; and

send the second partially decrypted and decoded data vector to the requesting computing device, wherein the requesting computing device is without access to the key stream.

8. The computer readable memory of claim 7, wherein an encryption key is converted into the key stream.

9. The computer readable memory of claim 7, wherein the first memory element further stores operational instructions that, when executed by the first storage unit, causes the first storage unit to partially dispersed storage error decode the first encoded and encrypted data slice by:

obtaining a square matrix, wherein the square matrix is derived from an encoding matrix of the dispersed storage error encoding; and

generating the first partially decoded and encrypted data vector based on the square matrix and the first encoded and encrypted data slice.

10. The computer readable memory of claim 7, wherein the second memory element further stores operational instructions that, when executed by the second storage unit, causes the second storage unit to partially dispersed storage error decode the second encoded and encrypted data slice by:

obtaining a square matrix, wherein the square matrix is derived from an encoding matrix of the dispersed storage error encoding; and

generating the second partially decoded and encrypted data vector based on the square matrix and the second encoded and encrypted data slice.