System for controlling access to a secure system by verifying acceptability of proposed password by using hashing and group of unacceptable passwords

Claim 5

The method of claim 2, further comprising the computer-implemented step of: if said proposed password is acceptable, assigning privileges in said secure system to said proposed password.

Claim 6

The method of claim 3 further comprising the computer-implemented steps of: if said proposed password is acceptable, setting all said indicators assigned by said mapping function to said proposed password such that said proposed password will not be acceptable if subsequently proposed, and at least partially disabling privileges of a previously privileged password so as to require a user possessing said previously privileged password to propose a new password.

Claim 7

The method of claim 2, further comprising the computer-implemented step of: enabling a user to apply said mapping function to further unacceptable passwords and set all said indicators assigned by said mapping function to each of said further unacceptable passwords.

Claim 8

The method of claim 2, further comprising the computer-implemented step of: if said proposed password is acceptable, setting all said indicators assigned by said mapping function to said proposed password such that said proposed password will not be acceptable if subsequently proposed.

Claim 9

The method of claim 2 adapted to verify acceptability of passwords proposed by users of a plurality of secure systems linked by a communications system, wherein said secure systems use a common table of indicators, said secure systems verify acceptability of proposed passwords using said common table of indicators according to the method of claim 2, and if a given secure system determines that a proposed password is acceptable, said given secure system sets all said indicators assigned by said mapping function to said proposed password, such that said proposed password will not be acceptable if subsequently proposed by a user of any of said secure systems, whereby a password which is acceptable will be accepted by only one of said secure systems.

Claim 10

The method of claim 2 wherein said mapping function comprises an encryption algorithm.

Claim 11

The method of claim 2 wherein said indicators are bits in a hash table and said mapping function is a hash function.

Claim 12

The method of claim 9 wherein said hash function comprises normalizing a text string for a password to a standard format to create a normalized text string.

Claim 13

The method of claim 10 wherein said standard format has a predetermined length.

Claim 14

The method of claim 10 wherein said text string has a length, and said normalizing comprises appending to said text string a character related to said length of said text string, creating a modified text string.

Claim 15

The method of claim 12 wherein said normalizing further comprises selectively adding a character to said modified text string, creating a twice modified text string having an odd length.

Claim 16

The method of claim 13 wherein said normalizing further comprises appending said twice modified text string to itself to create a thrice modified text string which exceeds a given length, and then truncating said thrice modified text string to said given length, creating said normalized text string.

Claim 17

The method of claim 10 or 14 wherein said hash function further comprises dividing said normalized text string into pieces, encrypting a predetermined input to an encrypted output using one or more of said pieces as an encryption key, and addressing bits in said hash table with said encrypted output.

Claim 18

The method of claim 15, further comprising the computer-implemented step of: if said proposed password is acceptable, setting all said indicators assigned by said mapping function to said proposed password such that said proposed password will not be acceptable if subsequently proposed, and wherein said encrypting is performed in accordance with a cryptographic technique secure against known plain-text attack, whereby an attacker who monitors changes to said hash table and thereby learns that one or more said indicators are assigned to a password, cannot determine said password from said indicators.

Claim 19

The method of claim 15 wherein said hash table has a length, said encrypting step is repeated N times on N of said pieces to create N encrypted outputs, said N encrypted outputs are split to generate final outputs, and one or more bit addresses in said hash table are computed from one or more of said final outputs by computing a modulo quotient of a final output with said length of said hash table.

Claim 20

The method of claim 16 wherein said cryptographic technique is the Data Encryption Standard.

Claim 21

Apparatus for controlling access to a secure system by verifying acceptability of proposed password from a user of said secure system, comprising a stored table of indicators, a mapper that assigns one or more indicators to a password such that one indicator may be assigned to more than one password, an initializer that applies said mapper to one or more unacceptable passwords, and sets all indicators assigned by said mapper to said unacceptable passwords, and a verifier that applies said mapper to said proposed password and checks whether any indicator assigned by said mapper to said proposed password is not set, and, if an indicator assigned by said mapper to said proposed password is not set, determines without error that said proposed password is not one of said unacceptable passwords and therefore is acceptable, and allows said user to access said secure system, otherwise, if an indicator assigned by said mapper to said proposed password is set, determines that said proposed password is unacceptable and frustrates said user from accessing said secure system.

Claim 22

Apparatus for controlling access to a secure system by verifying acceptability of proposed password from a user of said secure system, comprising a stored table of indicators, a mapper that assigns one or more indicators to a password such that one indicator may be assigned to more than one password, an initializer that applies said mapper to one or more unacceptable passwords, and sets all indicators assigned by said mapper to said unacceptable passwords, and a verifier that applies said mapper to said proposed password and checks whether any indicator assigned by said mapper to said proposed password is not set, and, if an indicator assigned by said mapper to said proposed password is not set, determines without error that said proposed password is not one of said unacceptable passwords and therefore is acceptable, and allows said user to access said secure system, otherwise, if an indicator assigned by said mapper to said proposed password is set, determines that said proposed password is unacceptable and frustrates said user from accessing said secure system.

Claim 23

The apparatus of claim 19, further comprising a privilege assigner that assigns privileges in said secure system to said proposed password, said privilege assigner being invoked if said verifier determines that said proposed password is acceptable.

Claim 24

The apparatus of claim 20 further comprising a modifier that applies said mapper to said proposed password and sets all said indicators assigned by said mapper to said proposed password, said modifier being invoked if said verifier determines that said proposed password is acceptable, such that said proposed password will not be acceptable if subsequently proposed, and wherein said privilege assigner at least partially disables privileges of a previously privileged password so as to require a user possessing said previously privileged password to propose a new password.

Claim 25

The apparatus of claim 19, further comprising a modifier that enables a user to apply said mapper to further unacceptable passwords and set all said indicators assigned by said mapper to each of said further unacceptable passwords.

Claim 26

The method of claim 19, further comprising a modifier that applies said mapper to said proposed password and sets all said indicators assigned by said mapper to said proposed password, said modifier being invoked if said verifier determines that said proposed password is acceptable, such that said proposed password will not be acceptable if subsequently proposed.

Claim 27

The apparatus of claim 23 used to verify acceptability of passwords proposed by users of a plurality of secure systems linked by a communications system, wherein each secure system invokes said verifier to verify acceptability of a password proposed for said system, and invokes said modifier to set all said indicators assigned by said mapper to said proposed password if said verifier determines that said proposed password is acceptable, whereby a password which is acceptable will be accepted by only one of said secure systems.

Claim 28

The apparatus of claim 19 wherein said mapper comprises an encrypter that encrypts proposed passwords.

Claim 29

The apparatus of claim 19 wherein said stored table of indicators is a hash table and said mapper comprises a hash function unit that performs a hash function.

Claim 30

The apparatus of claim 26 wherein said hash function unit comprises a normalizer that normalizes a text string for a password to a standard format to create a normalized text string.

Claim 31

The apparatus of claim 27 wherein said standard format has a predetermined length.

Claim 32

The apparatus of claim 27 wherein said text string has a length, and said normalizer comprises an appender that appends to said text string a character related to said length of said text string, creating a modified text string.

Claim 33

The apparatus of claim 29 wherein said appender selectively adds a character to said modified text string, creating a twice modified text string having an odd length.

Claim 34

The apparatus of claim 30 wherein said normalizer further comprises a repeater that appends said twice modified text string to itself to create a thrice modified text string which exceeds a given length, and then truncates said thrice modified text string to said given length, creating said normalized text string.

Claim 35

The apparatus of claim 27 or 31 wherein said hash function unit further comprises a divider that divides said normalized text string into pieces, an encrypter that encrypts a predetermined input to an encrypted output using one or more of said pieces as an encryption key, and an addresser that forms addresses of bits in said hash table using said encrypted output.

Claim 36

The apparatus of claim 32 wherein said hash table has a length, said encrypter encrypts N said pieces to create N encrypted outputs, and said addresser splits said N encrypted outputs to generate final outputs, and computes one or more bit addresses in said hash table from one or more of said final outputs by computing a modulo quotient of a final output with said length of said hash table.

Claim 37

The apparatus of claim 32 further comprising a modifier that applies said mapper to said proposed password and sets all said indicators assigned by said mapper to said proposed password, said modifier being invoked if said verifier determines that said proposed password is acceptable, such that said proposed password will not be acceptable if subsequently proposed, and wherein said encrypter encrypts in accordance with a cryptographic technique secure against known plain-text attack, whereby an attacker who monitors changes to said hash table and thereby learns that one or more indicators are assigned to a password, cannot determine said password from said indicators.

Claim 38

The apparatus of claim 34 wherein said cryptographic technique is the Data Encryption Standard.

Claim 39

Apparatus for verifying acceptability of a proposed password from a user of a secure system, comprising a stored table of indicators, a mapper that assigns one or more of said indicators to one or more passwords such that one of said indicators may be assigned to more than one of said passwords, an initializer that applies said mapper to one or more unacceptable passwords, and sets all said indicators assigned by said mapper to said unacceptable passwords, a verifier that applies said mapper to said proposed password and checks whether any one of said indicators assigned by said mapper to said proposed password is not set, and, if any one of said indicators assigned by said mapper to said proposed password is not set, determines without error that said proposed password is not one of said unacceptable passwords and therefore is acceptable, a privilege assigner that assigns privileges in said secure system to said proposed password, said privilege assigner being invoked if said verifier determines that said proposed password is acceptable, and a modifier that operates with respect to a password by applying said mapper to said password and setting all said indicators assigned by said mapper to said password, such that said password will not be acceptable if subsequently proposed, said modifier capable of being invoked with respect to further unacceptable passwords from a user, and also capable of being invoked with respect to said proposed password if said verifier determines that said proposed password is acceptable.

Claim 40

Apparatus for verifying acceptability of a proposed password from a user of a secure system, comprising a stored table of indicators, a mapper that assigns one or more of said indicators to one or more passwords such that one of said indicators may be assigned to more than one of said passwords, an initializer that applies said mapper to one or more unacceptable passwords, and sets all said indicators assigned by said mapper to said unacceptable passwords, a verifier that applies said mapper to said proposed password and checks whether any one of said indicators assigned by said mapper to said proposed password is not set, and, if any one of said indicators assigned by said mapper to said proposed password is not set, determines without error that said proposed password is not one of said unacceptable passwords and therefore is acceptable, a privilege assigner that assigns privileges in said secure system to said proposed password, said privilege assigner being invoked if said verifier determines that said proposed password is acceptable, and a modifier that operates with respect to a password by applying said mapper to said password and setting all said indicators assigned by said mapper to said password, such that said password will not be acceptable if subsequently proposed, said modifier capable of being invoked with respect to further unacceptable passwords from a user, and also capable of being invoked with respect to said proposed password if said verifier determines that said proposed password is acceptable.

Claim 41

Apparatus for verifying acceptability of a proposed password from a user of a secure system, comprising a stored hash table of bits, a hash function unit that assigns said bits in said hash table to passwords, such that one of said bits may be assigned to more than one of said passwords, comprising a normalizer that normalizes a text string for a password to create a normalized text string having a predetermined length, a divider that divides said normalized text string into pieces, an encrypter that encrypts a predetermined input to an encrypted output using one or more of said pieces as an encryption key, and an addresser that forms addresses of said bits in said hash table using said encrypted output, an initializer that applies said hash function unit to one or more acceptable passwords, and sets all said bits assigned by said mapper to said unacceptable passwords, a verifier that applies said hash function unit to said proposed password and checks whether any one of said bits assigned by said hash function unit to said proposed password is set, and, if one of said bits assigned by said hash function unit to said proposed password is not set, determines without error that said proposed password is not one said unacceptable passwords and therefore is acceptable and may be assigned privileges in said secure system, a privilege assigner that assigns privileges in said secure system to said proposed password, said privilege assigner being invoked if said verifier determines that said proposed password is acceptable, and a modifier that applies said hash function unit to said proposed password and sets all said bits assigned by said hash function unit to said password, such that said password will not be acceptable if subsequently proposed, said modifier capable of being invoked with respect to further unacceptable passwords from a user, and also capable of being invoked with respect to said proposed password if said verifier determines that said proposed password is acceptable.

Claim 42

Apparatus for verifying acceptability of a proposed password from a user of a secure system, comprising a stored hash table of bits, a hash function unit that assigns said bits in said hash table to passwords, such that one of said bits may be assigned to more than one of said passwords, comprising a normalizer that normalizes a text string for a password to create a normalized text string having a predetermined length, a divider that divides said normalized text string into pieces, an encrypter that encrypts a predetermined input to an encrypted output using one or more of said pieces as an encryption key, and an addresser that forms addresses of said bits in said hash table using said encrypted output, an initializer that applies said hash function unit to one or more acceptable passwords, and sets all said bits assigned by said mapper to said unacceptable passwords, a verifier that applies said hash function unit to said proposed password and checks whether any one of said bits assigned by said hash function unit to said proposed password is set, and, if one of said bits assigned by said hash function unit to said proposed password is not set, determines without error that said proposed password is not one said unacceptable passwords and therefore is acceptable and may be assigned privileges in said secure system, a privilege assigner that assigns privileges in said secure system to said proposed password, said privilege assigner being invoked if said verifier determines that said proposed password is acceptable, and a modifier that applies said hash function unit to said proposed password and sets all said bits assigned by said hash function unit to said password, such that said password will not be acceptable if subsequently proposed, said modifier capable of being invoked with respect to further unacceptable passwords from a user, and also capable of being invoked with respect to said proposed password if said verifier determines that said proposed password is acceptable.