Electrical computers and digital processing systems: support – Multiple computer communication using cryptography – Protection at a particular protocol layer
Reexamination Certificate
2001-06-29
2004-05-18
Gaffin, Jeffrey (Department: 2182)
Electrical computers and digital processing systems: support
Multiple computer communication using cryptography
Protection at a particular protocol layer
C713S152000, C713S158000, C380S241000
Reexamination Certificate
active
06738912
ABSTRACT:
The present invention relates to a method for securing data relating to users of a public key infrastructure according to claim
1
.
The present invention relates in particular to a method for securing data which are based on relations between certificate holders and institutions or closed user groups.
More particularly the present invention relates to a method for securing relational data, based on which, for example, business transactions are performed or access to a system may be granted by using an open, public certificate while privacy of the relations between certificate holders and institutions can be maintained.
BACKGROUND OF THE INVENTION
The emergence of the World wide Web access to the Internet has been accompanied by recent focus on financial transaction vulnerabilities, crypto system weaknesses and privacy issues. Fortunately, technological developments also made a variety of controls available for computer security including tokens, biometric verifiers, encryption, authentication and digital signature techniques using preferably asymmetrical public-key approaches (see [1], Richard C. Dorf, THE ELECTRICAL ENGINEERING HANDBOOK, 2nd Edition, CRC-Press, Boca Raton 1997, chapter 97, pages 2221-2234 and [7], A. Menezes, P. van Oorschot, S. Vanstone, HANDBOOK OF APPLIED CRYPTOGRAPHY, CRC-Press, Boca Raton 1997, chapter 1).
The basic objectives of encryption are secrecy, authentication (assurance of sender identity to recipient), and digital signatures (authentication plus assurance to sender and third parties that the signature had not been created by the recipient). This is normally referred to as non-repudiation, with further variants such as non-repudiation of origin, non-repudiation of sending and so on. Of further importance is integrity which means preventing interference in the information conveying process.
Almost all cryptosystems involve publicly known transformations of information, based on one or more keys, at least one of which is kept secret. The public-key cryptosystem disclosed 1976 by Diffie and Hellman is based on two keys, a private-key and a public-key, owned by users of this system.
As described in [2], U.S. Pat. No. 4,405,829 for the RSA cryptosystem explained below, the public-key cryptosystem provides enciphered communication between arbitrary pairs of people, without the necessity of their agreeing on an enciphering key beforehand. The Diffie and Hellman system also provides a way of creating for a digitised document a recognizable, unforgeable, document-dependent, digitised signature whose authenticity the signer cannot later deny.
The RSA cryptosystem (named after R. L. Rivest, A. Shamir and L. M. Adleman which in [2] are mentioned as inventors) is the most widely used public-key cryptosystem. RSA is a commutative transformation, which allows the private-key and the corresponding public-key to be used interchangeably as encryption and decryption keys, thus providing secrecy and authenticity on a secure channel between two parties A and B with no need for additional keys (see [1], pages 2225-2226).
Since, given only one key of an asymmetric key pair, it is practically infeasible to determine the other key, an owner A of a key pair may publish his public-key so that anyone can use this public-key to encrypt a message that only A can decipher with his private-key.
As described in [3], Marc Branchaud, A SURVEY OF PUBLIC-KEY INFRASTRUCTURES, Department of Computer Science, Mc Gill University, Montreal 1997, page 5, computing with public-key ciphers takes much longer than encoding the same message with a secret-key system. This has led to the practice of encrypting messages with a secret-key system such as DES and then encoding the secret-key with a public-key system such as RSA. In this case the public-key system securely transports the secret-key. In case that a message is sent secretly from A to B then, besides a secret-key, which is used optionally, only the key pair of B is used.
The described public-key system also allows owner A to sign a message to be sent to B with a digital signature. In this case the key pair of A is used. A encrypts the message or a corresponding hash of the message with his private-key which, on the other side of the transmission channel can be decrypted by B using A's public key. One key pair can therefore be used to receive an encrypted message or to send a digitally signed message.
B (and any third parties), who can decrypt with A's public-key a message signed by A, can therefore trust that A has signed the message as far as D can trust that the selected public-key truly belongs to A.
In order to ensure that public-keys can systematically be published and truly relate to the persons A, B, . . . indicated by attached public-key values, registration- and certification authorities (RA, CA) have been introduced to certify the relationship between a given key and a claimed identity.
According to [3], page 10 a public-key infrastructure, in its most simple form, is a system for publishing public-key values used in public-key cryptography. There are basic operations, namely registration, certification and validation, which are common to all public-key infrastructures.
Certification is the means by which registered public-key values, and information pertaining to those values, are published. A basic certificate therefore contains at least the public-key of the concerned subject, subject identification information, and identification information of the certifying authority.
The certificate is signed by the certifying authority with the certifying authority's private-key and can be validated with the publicly known public-key of the certifying authority. In other words a certificate is therefore an encyrypted message issued by the certifying authority declaring that the therein contained public-key relates to the enclosed subject identification information.
As described in [3], pages 19-21, authentication is a process provided by a public-key infrastructure. When a certifying authority certifies an entity and a user then validates that certification, the entity is said to have been authenticated.
The degree to which a user can trust the certificate's information and it's validity is a measure of the strength of the authentication.
[4], U.S. Pat. No. 6,202,151 B1 describes a biometric certification system and method which implement an end-to-end security mechanism binding the biometric identification of consumers with digital certificates.
Users can also be authenticated through something possessed such as a token or a smart card. Tokens are, as described in [1], pages 2228-2229, hand-carried devices that are normally intended to increase password security by assuring that passwords are used only once, thereby reducing the vulnerability to password compromise. Tokens may contain internally an algorithm, which either works in synchronisation with an identical algorithm in a host computer or which transform an input derived from a computer prompt into a password that matches the computer-transformed result. In a public-key infrastructure a token containing a private-key may used to sign a message as described above.
The degree of authentication of a user by means of a token is however in many cases not strong enough. A man, to which the token had been assigned, may, rightfully or not, deny at a later stage that the token actually belongs to him.
In order to significantly increase the degree of authentication, in the not yet published European Patent Application No. 01810513.0 it is proposed to register users by means of a token or an other secure device at an authority, preferably the registration authority of a public-key infrastructure based on credentials, including signed biometric data presented to said authority.
The biometric data are signed by means of a private key issued individually by the registration authority automatically for each token. In addition to signing the biometric data with the pr
Gaffin Jeffrey
Mai Rijue
Oliff & Berridg,e PLC
LandOfFree
Method for securing data relating to users of a public-key... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for securing data relating to users of a public-key..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for securing data relating to users of a public-key... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3266429