Data cryptography using control vectors

Claim 2

In a data processing system which processes cryptographic service requests for the performance of data cryptography functions on data using cryptographic keys which are associated with control vectors defining the functions which each key is allowed by its originator to perform, a method for validating that data cryptography functions requested for a cryptographic key have been authorised by the originator of the key, comprising the steps of: receiving a cryptographic service request for performing a data cryptography function on data using a cryptographic key in a cryptographic facility characterised by a secure boundary through which passes an input path and an output path; receiving a control vector associated with the cryptographic key and checking that the control vector authorises the data cryptography function which is requested by the cryptographic service request; signalling that the data cryptography function is authorised and initiating the performance of the requested data cryptography function with the cryptography key.

Claim 3

A method as claimed in claim 1, which further comprises storing in a storage means the cryptographic key in an encrypted form in which the cryptographic key is encrypted under a storage key which is a logical product of the associated control vector and a master key.

Claim 4

A method as claimed in claim 2, wherein the storage key is the exclusive-OR product of the associated control vector and the master key stored in the master key storage.

Claim 8

A method as claimed in claim 6, wherein the associated control vector further includes a usage field designating one of the following - - that the cryptographic key can perform encryption of the data; - that the cryptographic key cannot perform encryption of the data; - that the cryptographic key can perform decryption of the data; - that the cryptographic key cannot perform decryption of the data; - that the cryptographic key can perform data cryptography functions; - that the cryptographic key can perform message authentication functions; - that the cryptographic key can be used to generate a message authentication code on the data; - that the cryptographic key cannot be used to generate a message authentication code on the data; - that the cryptographic key can be used to verify a message authentication code on the data; - that the cryptographic key cannot be used to verify a message authentication code on the data; - that the cryptographic key cannot be used as the output data key in a translate ciphertext function; - that the cryptographic key can be used as the input data key in a translate ciphertext function - that the cryptographic key cannot be used as the input data key in a translate ciphertext function. - that the cryptographic key can perform data cryptography functions and further includes a subtype field designating that the cryptographic key is an ANSI data key.

Claim 9

A method as claimed in claim 6, wherein the associated control vector includes a type field designating that the cryptographic key can perform data cryptography functions and further includes an export control field which designates whether the local data processing system is allowed to export the cryptographic key and further designates whether a remote data processing system to which the local data processing system is connected, is allowed to re-export the cryptographic key.

Claim 10

A method as claimed in claim 6, wherein the associated control vector includes a type field designating that the cryptographic key can perform data cryptography functions and further includes a subtype field designating that the cryptographic key can perform data privacy functions.

Claim 11

A method as claimed in claim 9, wherein the associated control vector includes a type field designating that the cryptographic key can perform data cryptography functions and further includes a subtype field designating that a translate ciphertext function can be performed by the cryptographic key.

Claim 12

A method as claimed in claim 10, wherein the associated control vector further includes a usage field designating that the cryptographic key can be used as the output data key in a translate ciphertext function.

Claim 13

A method as claimed in claim 9, wherein the data cryptography function is session protection to protect the confidentiality of data transmissions between two communicating devices in the system which share a common data encrypting/decrypting key, permitting each device to both send and receive encrypted data, comprising the steps of: sharing a data privacy key between the devices; storing the data privacy key in operational form encrypted under a master key at each respective device; providing usage attributes for the control vector of each data privacy key for enciphering and deciphering, respectively, which enables each key to be used to both encipher and decipher data.

Claim 14

A method as claimed in claim 12, wherein the data cryptography function is file protection to protect the confidentiality of data files, wherein a single end user possesses a data encrypting/decrypting key permitting data to be encrypted for storage and to be decrypted for purposes of recovery of the file, further comprising the steps of: providing a data privacy key to the single end user; storing an encrypted form of the data privacy key with data which has been encrypted thereby; the data privacy key being stored in import form encrypted under a key encrypting key, with its associated control vector; providing usage attributes for the control vector of the data privacy key for enciphering and deciphering, thereby permitting the data file to be both encrypted and decrypted with the same key.

Claim 15

A method as claimed in claim 12, wherein the data cryptography function is an encrypted mail box in which each user of a plurality of users of the system has a data privacy key in two forms, the first form permitting data encryption and a second form permitting data decryption, the first form of the key being placed in the public directory accessible to all users of the mail box so that each registered key is recorded under one user identifier belonging to the user who registers the key, the second form of the key being private to the user to which it belongs, so that mail deposited in the mail box directed to a particular user in its encrypted form, can be decrypted only by that user - the intended recipient - comprising the steps of: providing a data privacy key which has been generated in two forms, the first form permitting enciphering only and the second form permitting deciphering; providing control vector usage attributes for the control vector associated with the data privacy key, which has for the first form of the data privacy key encipher only features and which has for the second form of the data privacy key decipher features.

Claim 16

A method as claimed in claim 12, wherein the data cryptography function is a ciphertext translation function to be performed at a ciphertext translation centre in a network in the system capable of securely translating encrypted data from encryption under a first data key to encryption under a second data key, comprising the steps of: generating a data key in two forms at a plurality of devices in the communications network, the first form being a data privacy key in operational form having an associated control vector which has encipher and decipher attributes, and a second form of the data key being a data translate key in the export form, suitable for export to a ciphertext translation centre in the network; receiving the data translate key at the ciphertext translation centre and converting the received data translation key to an operational form, the control vector associated with the data translation key having both translate-in and translate-out attributes; enciphering data at some first device which is transmitted to the ciphertext translation centre where it is translated to encipherment under the second data key known to some second device in the network connected to the ciphertext translation centre; transmitting the translated data from the centre to the second device where it is deciphered under the second data key.

Claim 17

A method as claimed in claim 15, wherein the ciphertext translation center cannot decrypt received inbound encrypted data nor can it encrypt data in a form comparable to outbound encrypted data.

Claim 18

A method as claimed in claim 12, wherein the data cryptography function is a peer-to-peer ciphertext translation for a communications network chain in the system which includes a first device which originates a communication, connected to a first ciphertext translation centre which in turn is connected to a second ciphertext translation centre which in turn is connected to a second network device, for a transmission of encrypted data from the first device through the first and second ciphertext translation centres to the second device, comprising the steps of: generating a first data key in the first network device in two forms, the first form being a data privacy key in operational form having an associated control vector which has encipher attributes, and a second form of the first data key being a data translate-in key in the export form, suitable for export to the first ciphertext translation centre; generating a second data key in the second network device in two forms, the first form being a data privacy key in operational form having an associated control vector which has decipher attributes, and a second form of the second data key being a data translate-out key in export form, suitable for export to the second ciphertext translation centre; generating a third data key in the first ciphertext translation centre in two forms, the first form being a data translate-out key and the second form being a data translate-in key, suitable for export to the second ciphertext translation centre; the first network device transmitting the first data key in its second form as a translate-in key to the first ciphertext translation centre; the second network device transmitting the second data key in its second form as a translate-out key to the second ciphertext translation centre; the first ciphertext translation centre transmitting the third data key in its second form as a translate-in key to the second ciphertext translation centre; the first network device encrypting data under the first data key in the first form and transmitting the encrypted data to the first ciphertext translation centre where the data is translated under the first data key in the second form to be encrypted under the third data key in the first form to be translated out and transmitted to the second ciphertext translation centre where the data is translated under the third data key in its second form into a form encrypted under the second data key in the second form where it is translated out and transmitted to the second network device where the data is then decrypted under the second data key in its first form.

Claim 19

A method as claimed in claim 12, wherein the data cryptography function is applied to an encrypted file under a first key so that a portion of the file can be re-encrypted under a second key for transmission to an intended receiver, without revealing the entire encrypted file, comprising the steps of: generating a first data key in two forms at a first device in the system, the first form being a data privacy key stored in operational form and the second form being a data translate-in key; encrypting a data file using the data privacy key and storing the file in its encrypted form in a data storage device; the first device generating a second data key in two forms, a translate-out key and a data decryption key; transmitting the data decryption key to a second device in the system connected to the first device; accessing the data file from the data storage device and re-enciphering a portion of the file from encipherment under the first data key to encipherment under the second data key via a translate ciphertext instruction using the first data key in the translate-in form and the second data key in the translate-out form and transmitting the re-enciphered portion of the data file from the first device to the second device; decrypting the transmitted portion of the data file by means of the decryption key form of the second key for use at the second device.

Claim 20

A method as claimed in claim 12, wherein the data cryptography function is message integrity, wherein the contents of a message is protected from unauthorised modification, comprising the steps of: providing a data/MAC key and an associated control vector having MAC generation and MAC verification attributes at both a sending station and a receiving station in a communications network in the system; computing an MAC value for a message to be sent from the sending station to the receiving station, employing the data/MAC key and the control vector at the sending station; transmitting the message and the computed MAC value from the sending station to the receiving station; computing a second value on the received message at the receiving station, employing the data/MAC key and the control vector and comparing the second computed MAC value with the transmitted MAC value; verifying the integrity of the message received at the receiving station when the two computed MAC values are equal.

Claim 21

A method as claimed in claim 12, wherein the data cryptography function is message authentication with non-repudiation, comprising the steps of: providing a data/MAC key with a first associated control vector having an MAC generation attribute at a sending station in a communications network in the system; providing the data/MAC key with a second control vector having an MAC verification attribute but not having an MAC generation attribute, at a receiving station in the communications network; computing a first value for the MAC on a message to be sent by the sending station over the communications network to the receiving station, using the the data/MAC key and the first control vector at the sending station; transmitting the message and the first MAC value from the sending station over the communications network to the receiving station; computing a second value for the MAC on the message received at the receiving station, using the data/MAC key and the second control vector, at the receiving station; verifying that the message has integrity and that it was sent by the sending station, when the first value for the MAC equals the second value for the MAC.

Claim 22

A method as claimed in claim 12, wherein the data cryptography function is a peer-to-peer ciphertext translation for a communications network chain in the system which includes a key issuing device in the network, a first device which originates a communication, connected to a first ciphertext translation centre which in turn is connected to a second ciphertext translation centre which in turn is connected to a second network device, for a transmission of encrypted data from the first device through the first and second ciphertext translation centres to the second device, comprising the steps of: generating a first data key in the first network device in two forms, the first form being a data privacy key in operational form having an associated control vector which has encipher attributes, and a second form of the first data key being a data translate-in key in the export form, suitable for export to the first ciphertext translation centre; generating a second data key in the second network device in two forms, the first form being a data privacy key in operational form having an associated control vector which has decipher attributes, and a second form of the second data key being a data translate-out key in export form, suitable for export to the second ciphertext translation centre; generating a third data key in the key issuing device in two forms, the first form being a data translate-out key suitable for export to the first ciphertext translation centre and the second form being a data translate-in key, suitable for export to the second ciphertext translation centre; the first network device transmitting the first data key in its second form as a translate-in key to the first ciphertext translation centre; the second network device transmitting the second data key in its second form as a translate-out key to the second ciphertext translation centre; the first key issuing device transmitting the third data key in its first form as a translate-out key to the first ciphertext translation centre and transmitting the third data key in its second form as a translate-in key to the second ciphertext translation centre; the first network device encrypting data under the first data key in its first form and transmitting the encrypted data to the first ciphertext translation centre where the data is translated under the first data key in the second form to be encrypted under the third data key in the first form to be translated out and transmitted to the second ciphertext translation centre where the data is translated under the third data key in the second form into a form encrypted under the second data key in the second form where it is translated out and transmitted to the second network device where the data is then decrypted under the second data key in the first form.

Claim 23

In a data processing system which processes cryptographic service requests for performing data cryptography functions on data using cryptographic keys which are associated with control vectors defining the functions which each key is allowed by its originator to perform, apparatus for performing the method of claim 1, comprising: a cryptographic facility characterised by a secure boundary through which passes an input path for receiving the cryptographic service requests, data, cryptographic keys and their associated control vectors, and an output path for providing responses thereto, there being included within the boundary a cryptographic instruction storage coupled to the input path, a control vector checking means and a crytographic processing means coupled to the instruction storage, and a master key storage coupled to the processing means, for providing a secure location for executing data cryptography functions in response to the received service requests; the cryptographic control means receiving over the input path a cryptographic service request for performing a data cryptography function with a cryptographic key; the control vector checking means having an input coupled to the input path for receiving a control vector associated with the cryptographic key and an input coupled to the cryptographic control means, for receiving control signals to initiate checking that the control vector authorises the data cryptography function which is requested by the cryptographic service request; the control vector checking means having an authorisation output coupled to an input of the cryptographic processing means, for signalling that the data cryptography function is authorised, the receipt of which by the cryptographic processing means initiates the performance of the requested data cryptography function with the cryptographic key.

Claim 24

Apparatus as claimed in claim 22, which further comprises: a cryptographic key storage means coupled to the cryptographic facility over the input and output paths, for storing the cryptographic key in an encrypted form in which the cryptographic key is encrypted under a storage key which is a logical product of the associated control vector and a master key stored in the master key storage; the cryptographic control means receiving over the input path a cryptographic service request for performing a data cryptography function which includes recovering the cryptographic key from the cryptographic key storage means and the control vector checking means outputting in response thereto, an authorisation signal to the cryptographic processing means that the requested data cryptography function is authorised; the cryptographic processing means operating in response to the authorisation signal, to receive the encrypted form of the cryptographic key from the cryptographic key storage means and to decrypt the encrypted form under the storage key which is a logical product of the associated control vector and the master key stored in the master key storage; the cryptographic processing means further operating in response to the authorisation signal, to receive the data from the input path and to complete performing the requested data cryptography function on the data with the cryptographic key.

Claim 25

Apparatus as claimed in claim 22 or 23, which further comprises: a working key storage within the cryptographic facility coupled to the cryptographic processing means, for providing a secure location for the storage of working keys.

Claim 26

Apparatus as claimed in any of claims 22 to 24 , in which the working key storage stores a plurality of working keys and their associated control vectors in clear text form.

Claim 27

Apparatus as claimed in any of claims 22 to 25, which further comprises: the cryptographic facility receiving over the input path a cryptographic service request for performing a data cryptography function; the control vector checking means checking the associated control vector accessed from the working key storage and outputting an authorisation signal to the cryptographic processing means that the cryptographic service request is authorised using the respective key accessed from the working key storage.

Claim 28

Apparatus as claimed in any of claims 22 to 26, in which the working keys are stored in the working key storage as the exclusive-OR product of each key with its respective control vector.

Claim 29

Apparatus as claimed in any of claims 22 to 27, in which the cryptographic facility receives over the input path a cryptographic service request for performing a data cryptography function and also receiving the corresponding associated control vector which undergoes control vector checking in the control vector checking means; the control vector checking means outputs an authorisation signal to the cryptographic processing means that the cryptographic service request is authorised, the corresponding exclusive-OR product of the control vector and its respective key then being exclusive-ORed with the control vector in order to recover the key for the requested cryptographic operation.

Claim 30

Apparatus as claimed in claim 22 or claim 23, which further comprises: a working key storage within the cryptographic facility coupled to the cryptographic processing means, for storing the exclusive-OR product of working keys and their associated control vectors; the cryptographic instruction storage receiving over the input path a cryptographic service request and the corresponding associated control vector, for performing a data cryptography function; the control vector checking means checking the control vector and outputting in response thereto, an authorisation signal to the cryptographic processing means that the requested data cryptography function is authorised; the cryptographic processing means operating in response to the authorisation signal, to perform an exclusive-OR operation between the control vector and the product which has been accessed from the working key storage, yielding the working key in clear text form; the cryptographic processing means further operating in response to the authorisation signal, to complete performing the requested data cryptography function with the cryptographic key.