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| java.lang.Object
 com.Ostermiller.util.RandPass
| RandPass | | public class RandPass (Code) | | Generates a random String using a cryptographically
secure random number generator.
The alphabet (characters used in the passwords generated)
may be specified, and the random number generator can be
externally supplied.
Care should be taken when using methods that limit the types
of passwords may be generated. Using an alphabet that is too
small, using passwords that are too short, requiring too many
of a certain type of character, or not allowing repetition,
may decrease security.
More information about this class is available from ostermiller.org.
author:
Stephen Ostermiller http://ostermiller.org/contact.pl?regarding=Java+Utilities
since:
ostermillerutils 1.00.00 |
| Field Summary | |
| final public static char[] | LETTERS_ALPHABET
Alphabet consisting of upper and lower case letters A-Z. | | final public static char[] | LOWERCASE_LETTERS_ALPHABET
Alphabet consisting of the lower case letters A-Z. | | final public static char[] | LOWERCASE_LETTERS_AND_NUMBERS_ALPHABET
Alphabet consisting of the lower case letters A-Z and
the digits 0-9. | | final public static char[] | NONCONFUSING_ALPHABET
Alphabet consisting of upper and lower case letters A-Z and
the digits 0-9 but with characters that are often mistaken
for each other when typed removed. | | final public static char[] | NUMBERS_AND_LETTERS_ALPHABET
Alphabet consisting of upper and lower case letters A-Z and
the digits 0-9. | | final public static char[] | PRINTABLE_ALPHABET
Alphabet consisting of all the printable ASCII characters. | | final public static char[] | SYMBOLS_ALPHABET
Alphabet consisting of all the printable ASCII symbols. | | final public static char[] | UPPERCASE_LETTERS_ALPHABET
Alphabet consisting of the upper letters A-Z. | | protected char[] | alphabet
Set of characters which may be
used in the generated passwords. | | protected char[] | firstAlphabet
Set of characters which may be
used for the first character
in the generated passwords. | | protected static ResourceBundle | labels
Locale specific strings displayed to the user. | | protected char[] | lastAlphabet
Set of characters which may be
used for the last character
in the generated passwords. | | protected SecureRandom | rand
Random number generator used. | | protected int | repetition
One less than the maximum number of repeated characters
that are allowed in a password. | | final public static String | version
|
| Constructor Summary | |
| public | RandPass()
Create a new random password generator
with the default secure random number generator
and default NONCONFUSING alphabet for all characters. | | public | RandPass(SecureRandom rand)
Create a new random password generator
with the given secure random number generator
and default NONCONFUSING alphabet for all characters. | | public | RandPass(char[] alphabet)
Create a new random password generator
with the default secure random number generator
and given alphabet for all characters. | | public | RandPass(SecureRandom rand, char[] alphabet)
Create a new random password generator
with the given secure random number generator
and given alphabet for all characters. |
| Method Summary | |
| public void | addRequirement(char[] alphabet, int num)
Require that a certain number of characters from an
alphabet be present in generated passwords. | | public void | addVerifier(PasswordVerifier verifier)
Add a class that will verify passwords. | | public String | getPass(int length)
Generate a random password of the given length.
NOTE: Strings can not be modified. | | public String | getPass()
Generate a random password of the default length (8).
NOTE: Strings can not be modified. | | public char[] | getPassChars(char[] pass)
Fill the given buffer with random characters.
Using this method, the password character array can easily
be reused for efficiency, or overwritten with new random
characters for security.
NOTE: If it is possible for a hacker to examine memory to find passwords,
the password should be overwritten in memory as soon as possible after i
is no longer in use.
Parameters:
pass - buffer that will hold the password. | | public char[] | getPassChars(int length)
Generate a random password of the given length.
NOTE: If it is possible for a hacker to examine memory to find passwords,
the password should be overwritten in memory as soon as possible after i
is no longer in use.
Parameters:
length - The desired length of the generated password. | | public char[] | getPassChars()
Generate a random password of the default length (8). | | public static void | main(String[] args)
Generate a random passwords. | | public void | setAlphabet(char[] alphabet)
Set the alphabet used by this random password generator. | | public void | setFirstAlphabet(char[] alphabet)
Set the alphabet used by this random password generator for the first character
of passwords. | | public void | setLastAlphabet(char[] alphabet)
Set the alphabet used by this random password generator for the last character
of passwords. | | public void | setMaxRepetition(int rep)
Set the maximum number of characters that may appear in sequence more than
once in a password. | | public void | setRandomGenerator(SecureRandom rand)
Set the random number generator used by this random password generator. |
| LETTERS_ALPHABET | | final public static char[] LETTERS_ALPHABET(Code) | | Alphabet consisting of upper and lower case letters A-Z.
since:
ostermillerutils 1.00.00 |
| LOWERCASE_LETTERS_ALPHABET | | final public static char[] LOWERCASE_LETTERS_ALPHABET(Code) | | Alphabet consisting of the lower case letters A-Z.
since:
ostermillerutils 1.00.00 |
| LOWERCASE_LETTERS_AND_NUMBERS_ALPHABET | | final public static char[] LOWERCASE_LETTERS_AND_NUMBERS_ALPHABET(Code) | | Alphabet consisting of the lower case letters A-Z and
the digits 0-9.
since:
ostermillerutils 1.00.00 |
| NONCONFUSING_ALPHABET | | final public static char[] NONCONFUSING_ALPHABET(Code) | | Alphabet consisting of upper and lower case letters A-Z and
the digits 0-9 but with characters that are often mistaken
for each other when typed removed. (I,L,O,U,V,i,l,o,u,v,0,1)
since:
ostermillerutils 1.00.00 |
| NUMBERS_AND_LETTERS_ALPHABET | | final public static char[] NUMBERS_AND_LETTERS_ALPHABET(Code) | | Alphabet consisting of upper and lower case letters A-Z and
the digits 0-9.
since:
ostermillerutils 1.00.00 |
| PRINTABLE_ALPHABET | | final public static char[] PRINTABLE_ALPHABET(Code) | | Alphabet consisting of all the printable ASCII characters.
since:
ostermillerutils 1.00.00 |
| SYMBOLS_ALPHABET | | final public static char[] SYMBOLS_ALPHABET(Code) | | Alphabet consisting of all the printable ASCII symbols.
since:
ostermillerutils 1.00.00 |
| UPPERCASE_LETTERS_ALPHABET | | final public static char[] UPPERCASE_LETTERS_ALPHABET(Code) | | Alphabet consisting of the upper letters A-Z.
since:
ostermillerutils 1.00.00 |
| alphabet | | protected char[] alphabet(Code) | | Set of characters which may be
used in the generated passwords.
This value may not be null or have
no elements.
since:
ostermillerutils 1.00.00 |
| firstAlphabet | | protected char[] firstAlphabet(Code) | | Set of characters which may be
used for the first character
in the generated passwords.
This value may be null but it must
have at least one element otherwise.
since:
ostermillerutils 1.00.00 |
| labels | | protected static ResourceBundle labels(Code) | | Locale specific strings displayed to the user.
since:
ostermillerutils 1.00.00 |
| lastAlphabet | | protected char[] lastAlphabet(Code) | | Set of characters which may be
used for the last character
in the generated passwords.
This value may be null but it must
have at least one element otherwise.
since:
ostermillerutils 1.00.00 |
| rand | | protected SecureRandom rand(Code) | | Random number generator used.
since:
ostermillerutils 1.00.00 |
| repetition | | protected int repetition(Code) | | One less than the maximum number of repeated characters
that are allowed in a password.
Set to -1 to disable this feature.
since:
ostermillerutils 1.00.00 |
| version | | final public static String version(Code) | | Version number of this program
since:
ostermillerutils 1.00.00 |
| RandPass | | public RandPass()(Code) | | Create a new random password generator
with the default secure random number generator
and default NONCONFUSING alphabet for all characters.
since:
ostermillerutils 1.00.00 |
| RandPass | | public RandPass(SecureRandom rand)(Code) | | Create a new random password generator
with the given secure random number generator
and default NONCONFUSING alphabet for all characters.
Parameters:
rand - Secure random number generator to use when generating passwords.
since:
ostermillerutils 1.00.00 |
| RandPass | | public RandPass(char[] alphabet)(Code) | | Create a new random password generator
with the default secure random number generator
and given alphabet for all characters.
Parameters:
alphabet - Characters allowed in generated passwords.
since:
ostermillerutils 1.00.00 |
| RandPass | | public RandPass(SecureRandom rand, char[] alphabet)(Code) | | Create a new random password generator
with the given secure random number generator
and given alphabet for all characters.
Parameters:
rand - Secure random number generator to use when generating passwords.
Parameters:
alphabet - Characters allowed in generated passwords.
since:
ostermillerutils 1.00.00 |
| addRequirement | | public void addRequirement(char[] alphabet, int num)(Code) | | Require that a certain number of characters from an
alphabet be present in generated passwords.
Parameters:
alphabet - set of letters that must be present
Parameters:
num - number of letters from the alphabet that must be present.
since:
ostermillerutils 1.00.00 |
| addVerifier | | public void addVerifier(PasswordVerifier verifier)(Code) | | Add a class that will verify passwords. No password
will be returned unless all verifiers approve of it.
Parameters:
verifier - class that performs verification of password.
since:
ostermillerutils 1.00.00 |
| getPass | | public String getPass(int length)(Code) | | Generate a random password of the given length.
NOTE: Strings can not be modified. If it is possible
for a hacker to examine memory to find passwords, getPassChars()
should be used so that the password can be zeroed out of memory
when no longer in use.
Parameters:
length - The desired length of the generated password. a random password
See Also: RandPass.getPassChars(int)
since:
ostermillerutils 1.00.00 |
| getPass | | public String getPass()(Code) | | Generate a random password of the default length (8).
NOTE: Strings can not be modified. If it is possible
for a hacker to examine memory to find passwords, getPassChars()
should be used so that the password can be zeroed out of memory
when no longer in use.
a random password
See Also: RandPass.getPassChars()
since:
ostermillerutils 1.00.00 |
| getPassChars | | public char[] getPassChars(char[] pass)(Code) | | Fill the given buffer with random characters.
Using this method, the password character array can easily
be reused for efficiency, or overwritten with new random
characters for security.
NOTE: If it is possible for a hacker to examine memory to find passwords,
the password should be overwritten in memory as soon as possible after i
is no longer in use.
Parameters:
pass - buffer that will hold the password. the buffer, filled with random characters.
since:
ostermillerutils 1.00.00 |
| getPassChars | | public char[] getPassChars(int length)(Code) | | Generate a random password of the given length.
NOTE: If it is possible for a hacker to examine memory to find passwords,
the password should be overwritten in memory as soon as possible after i
is no longer in use.
Parameters:
length - The desired length of the generated password. a random password
since:
ostermillerutils 1.00.00 |
| getPassChars | | public char[] getPassChars()(Code) | | Generate a random password of the default length (8).
NOTE: If it is possible for a hacker to examine memory to find passwords,
the password should be overwritten in memory as soon as possible after i
is no longer in use.
a random password
since:
ostermillerutils 1.00.00 |
| main | | public static void main(String[] args) throws Exception(Code) | | Generate a random passwords.
Run with --help argument for more information.
Parameters:
args - Command line arguments.
throws:
Exception - errors
since:
ostermillerutils 1.00.00 |
| setAlphabet | | public void setAlphabet(char[] alphabet)(Code) | | Set the alphabet used by this random password generator.
Parameters:
alphabet - Characters allowed in generated passwords.
throws:
NullPointerException - if the alphabet is null.
throws:
ArrayIndexOutOfBoundsException - if the alphabet has no elements.
since:
ostermillerutils 1.00.00 |
| setFirstAlphabet | | public void setFirstAlphabet(char[] alphabet)(Code) | | Set the alphabet used by this random password generator for the first character
of passwords.
If the alphabet for the first character is set to null or has no elements, the main alphabet will
be used for the first character.
Parameters:
alphabet - Characters allowed for the first character of the passwords.
since:
ostermillerutils 1.00.00 |
| setLastAlphabet | | public void setLastAlphabet(char[] alphabet)(Code) | | Set the alphabet used by this random password generator for the last character
of passwords.
If the alphabet for the last character is set to null or has no elements, the main alphabet will
be used for the last character.
Parameters:
alphabet - Characters allowed for the last character of the passwords.
since:
ostermillerutils 1.00.00 |
| setMaxRepetition | | public void setMaxRepetition(int rep)(Code) | | Set the maximum number of characters that may appear in sequence more than
once in a password. Your alphabet must be large enough to handle this
option. If your alphabet is {'a', 'b'} and you want 8 character passwords
in which no character appears twice (repetition 1) you are out of luck.
In such instances your request for no repetition will be ignored.
For example setRepetition(3) will allow a password ababab but not allow
abcabc.
Using this method can greatly reduce the pool of passwords that are generated.
For example if only one repetition is allowed then the pool of passwords
is the permutation of the alphabet rather than the combination.
Parameters:
rep - Maximum character repetition.
since:
ostermillerutils 1.00.00 |
| setRandomGenerator | | public void setRandomGenerator(SecureRandom rand)(Code) | | Set the random number generator used by this random password generator.
Parameters:
rand - Secure random number generator to use when generating passwords.
since:
ostermillerutils 1.00.00 |
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