Password strength checking method and appartatus and program and recording medium thereof, password creation assisting method and program thereof, and password creating method and program thereof

Abstract

A password strength checking method includes operations of inputting a password to be checked, generating a plaintext password candidate according to the same generation procedure as that used by a password guessing tool, determining whether or not the inputted password and the generated password candidate match each other, directing generation of the next password candidate when the match is not determined, determining strength of the inputted password based on the number of the generated password candidates when the match is determined, and outputting information of the determined password strength.

1 . A password strength checking method comprising:
 inputting a password to be checked;   generating a password candidate according to a generation procedure which is used for generating the password to be checked in a password guessing tool;   iteratively determining whether or not the input password and the generated password candidate match each other, and generating another password candidate, if the input password candidate and the generated password candidate do not match;   determining a strength of the input password based on a number of generated passwords until the input password and a generated password matched each other; and   outputting the determined strength of the input password.   
   
   
       2 . The password strength checking method according to  claim 1 , wherein the inputting includes presenting the input password to a user in an unreadable form, and requesting the user to input the password again, and checks the strength of the input password only when the two input passwords match each other. 
   
   
       3 . The password strength checking method according to  claim 1 , wherein the inputting includes inputting user attribute information, and strength checking for the input password is not executed if the input user attribute information and the input password match each other. 
   
   
       4 . The password strength checking method according to  claim 1 , wherein the determining estimates a time required for the password guessing tool to guess the input password based on a number of generated password candidates to determine the time as a password strength. 
   
   
       5 . The password strength checking method according to  claim 1 , wherein the determining calculates numerical information based on a ratio value of the possible maximum number of password candidates to be generated and the number of the generated password candidates, to determine the numerical information as a password strength. 
   
   
       6 . The password strength checking method according to  claim 1 , wherein the outputting includes outputting information of a rank among passwords, which have been checked and for which password strength has been determined, which is identified based on the determined password strength. 
   
   
       7 . A password strength checking apparatus comprising:
 means for inputting a password to be checked;   means for generating a password candidate according to a generation procedure which is used for generating the password to be checked by a password guessing tool;   means for determining whether or not the input password and the generated password candidate match each other;   means for directing generation of another password candidate when the match is not determined;   means for determining strength of the input password based on a number of generated password candidates until the match is determined; and   means for outputting the determined strength of the input password.   
   
   
       8 . A recording medium recording a password strength checking program, wherein the program causes a computer to execute:
 inputting a password to be checked;   generating a password candidate according to a generation procedure which is used for generating the password to be checked in a password guessing tool;   determining whether or not the input password and the generated password candidate match each other;   generating another password candidate when the match is not determined;   determining strength of the input password based on a number of generated password candidates until the match is determined; and   outputting the determined strength of the input password.   
   
   
       9 . A password creation assisting method comprising:
 inputting a password to be targeted by creation assistance and characters places information for identifying a character string to be checked that is included in the password;   using a password candidate generating tool for generating a password candidate according to a generation procedure which is used for generating the password to be checked in a password guessing tool, to obtain a number of password candidates which have been generated until a password candidate having the character string at the characters places is first generated;   calculating strength of the character string based on the obtained number of generated password candidates; and   outputting the calculated strength of the character string.   
   
   
       10 . A password creation assisting method comprising:
 inputting a password to be targeted by creation assistance;   extracting all or a part of characters composing the input password together with places of the characters;   identifying, for each of the extracted characters, a character rank at the extracted character position, with the extracted characters and the characters places as a key, by referring to a table group recording character rank information for each character position, the table group being provided for a password guessing tool to use when guessing a password by checking all possible passwords;   calculating character strength for each of the extracted characters based on the identified character rank; and   outputting the calculated character strength.   
   
   
       11 . A password creation assisting method comprising:
 inputting a password to be targeted by creation assistance;   extracting character strings increasing in length by an increment of one character, with the first character of the input password as a top character;   using a password candidate generating tool for generating a password candidate according to a generation procedure which is used for generating the password to be checked in a password guessing tool, to obtain, for each of the extracted character strings, a number of password candidates which have been generated until a password candidate having the character string at the same characters places is first generated;   calculating a character strength transition value of the input password based on the obtained number of the generated password candidates; and   outputting the calculated character strength transition value.   
   
   
       12 . A computer readable medium storing a program for assisting password creation executed in a computer, wherein the program causes a computer to execute:
 inputting a password to be targeted by creation assistance and characters places information for identifying a character string to be checked that is included in the password;   using a password candidate generating tool for generating a password candidate according to a generation procedure which is used for generating the password to be checked in a password guessing tool, to obtain a number of password candidates which have been generated by the time a password candidate having the character string at the characters places is first generated;   calculating strength of the character string based on the obtained number of generated password candidates; and   outputting the calculated strength of the character string.   
   
   
       13 . A computer readable medium storing a program for assisting password creation executed in a computer, wherein the program causes a computer to execute:
 inputting a password to be targeted by creation assistance;   extracting all or a part of characters composing the input password together with positions of the characters;   identifying, for each of the extracted characters, a character rank at the extracted character position, with the extracted characters and the characters positions as a key, by referring to a table group recording character rank information for each character position, the table group being provided for a password guessing tool to use when guessing a password by checking all possible passwords;   calculating character strength for each of the extracted characters based on the identified character rank; and   outputting the calculated character strength.   
   
   
       14 . A computer readable medium storing a program for assisting password creation executed in a computer, wherein the computer causes a computer to execute:
 inputting a password to be targeted by creation assistance;   extracting character strings increasing in length by an increment of one character, with the first character of the input password as a top character;   using a password candidate generating tool for generating a password candidate according to the same generation procedure as that used by a password guessing tool, to obtain, for each of the extracted character strings, a number of password candidates which have been generated until a password candidate having the character string at the same characters places is first generated;   calculating a character strength transition value of the input password based on the obtained number of the generated password candidates; and   outputting the calculated character strength transition value.