公开(公告)号：JP2001273286A

公开(公告)日：2001-10-05

申请号：JP2001002365

申请日：2001-01-10

Applicant: IBM

Inventor： INCERTIS CARRO FERNANDO ,  MATYAS STEPHEN M JR

IPC: G06F17/21 ,  G06F12/14 ,  G06F21/24 ,  G06T1/00 ,  H04L9/32 ,  H04N1/387

Abstract: PROBLEM TO BE SOLVED: To provide a method for merging information required for authenticating a text document to the text itself of the document. SOLUTION: A text 100 to be marked is edited and a text 120 in a standard form suited to a model is provided. Next, while using this text in the standard form and a secret key 130 as entry, the unique combination of positions of inter-word blank character is calculated and an extra blank is inserted thereto so that the document of a marked text 150 can be provided. The received marked text document is authenticated by a receiver who shares the secret key and compares the received text document with the marked text document and when both the documents are strictly coincident, the received text document is accepted as true one however when these documents are not coincident, the document is refused as a false.

公开(公告)号：JPH1041932A

公开(公告)日：1998-02-13

申请号：JP7150097

申请日：1997-03-25

Applicant: IBM

Inventor： JOHNSON DONALD B ,  KARGER PAUL A ,  KAUFMAN CHARLES W JR ,  MATYAS STEPHEN M JR ,  YUNG MARCEL M ,  ZUNIC NEVENKO

IPC: H04L9/08 ,  H04L9/10

Abstract: PROBLEM TO BE SOLVED: To provide the key recovery system handling requests in contention of different entities by several persons by using each of a plurality of of common share keys with respect to a plurality of key recovery agents. SOLUTION: A PQR value 102 to consent to a secret value 102 referred to as a PQR for mutual communication is made up of P, Q values 104, 106 in m-bit and an R value 108 in m-bit. The P value 104 is used in common for a 1st key recovery agent of each country and the Q value 106 is used in common by a 2nd key recovery agent. The R value 108 is used in common between users. In order to generate a cryptographic key, the P value 104 and the Q value 106 are processed by an exclusive OR (XOR) and a resulting value (112) in 112-bits is generated. Then the resulting value 112 is linked with the R value 108 to generate an intermediate value 114 in 168 bits. The intermediate value 114 is hash-processed (116) and a final key value 118 is extracted.

公开(公告)号：CA2197915C

公开(公告)日：2002-12-10

申请号：CA2197915

申请日：1997-02-05

Applicant: IBM

Inventor： JOHNSON DONALD B ,  KARGER PAUL A ,  KAUFMAN CHARLES W JR ,  MATYAS STEPHEN M JR ,  YUNG MARCEL M ,  ZUNIC NEVENKO

IPC: H04L9/08 ,  H04L9/10 ,  H04L9/14

Abstract: A cryptographic key recovery system for generating a cryptographic key for use by a pair of communicating parties while simultaneously providing fo r its recovery using one or more key recover agents. A plurality of m-bit shared k ey parts (P, Q) are generated which are shared with respective key recovery agents, while an n-bit nonshared key part (R) is generated that is not share d with any key recovery agent. The shared key parts (P, Q) are combined to generate an m-bit value which is concatenated with the nonshared key part (R ) to generate an (m + n)-bit value from which an encryption key is generated. The cryptographic system has the effective work factor of an n-bit key to al l of the key recovery agents acting in concert, but has the effective work fac tor of an (m + n)-bit to any other combination of third parties. The quantity n is selected to make authorized key recovery feasible, but not so trivial as to permit routine decryption of intercepted communications, while the quantity m is selected to make decryption by unauthorized third parties infeasible. Means are provided for verifying that the shared key parts have been shared with the k ey recovery agents before permitting encrypted communications using the thus generated key.

公开(公告)号：CA2197915A1

公开(公告)日：1997-10-11

申请号：CA2197915

申请日：1997-02-05

Applicant: IBM

Inventor： JOHNSON DONALD B ,  KARGER PAUL A ,  KAUFMAN CHARLES W JR ,  MATYAS STEPHEN M JR ,  YUNG MARCEL M ,  ZUNIC NEVENKO

IPC: H04L9/08 ,  H04L9/10 ,  H04L9/14

Abstract: A cryptographic key recovery system for generating a cryptographic key for use by a pair of communicating parties while simultaneously providing for its recovery using one or more key recover agents. A plurality of m-bit shared key parts (P, Q) are generated which are shared with respective key recovery agents, while an n-bit nonshared key part (R) is generated that is not shared with any key recovery agent. The shared key parts (P, Q) are combined to generate an m-bit value which is concatenated with the nonshared key part (R) to generate an (m + n)-bit value from which an encryption key is generated. The cryptographic system has the effective work factor of an n-bit key to all of the key recovery agents acting in concert, but has the effective work factor of an (m + n)-bit to any other combination of third parties. The quantity n is selected to make authorized key recovery feasible, but not so trivial as to permit routine decryption of intercepted communications, while the quantity m is selected to make decryption by unauthorized third parties infeasible. Means are provided for verifying that the shared key parts have been shared with the key recovery agents before permitting encrypted communications using the thus generated key.

公开(公告)号：CA1292790C

公开(公告)日：1991-12-03

申请号：CA566675

申请日：1988-05-12

Applicant: IBM

Inventor： MATYAS STEPHEN M JR ,  MEYER CARL H W ,  BRACHTL BRUNO O

IPC: G09C1/00 ,  H04L9/08 ,  H04L9/00

Abstract: KI9-85-015 A method for controlling the use of a cryptographic key at a using station by a generating station in a network of generating and using stations is disclosed. A control value specifying the use of the cryptographic key is transmitted with a generated cryptographic key to at least two designated using stations one of which may be the generating station. Each of the generating and using stations have cryptographic facilities that securely store a master key. Two techniques are described for controlling the use of the cryptographic key. In the first, the key and the control value are authenticated via a special authentication code before use by the using station. In the second, the key and control value are coupled during key generation such that the key is recovered only if a correct control value is specified. In addition, two techniques are described for controlling who may use the cryptographic key. In the first, each using station has a unique secret transport key shared with the generating station which generates the key in such a way that it can be recovered or regenerated only by the designated using station possessing the correct secret transport key. In the second, secret transport keys are shared by pairs of using stations and cryptographic separation is achieved by using public or nonsecret values unique to each using station.