Linux Dictionary Generation tool-crunch and Rtgen

The so-called password dictionary is mainly used in conjunction with password cracking software, the password dictionary includes many people habitually set the password. This can improve the password cracking software password cracking success rate and hit ratio, shorten the password cracking time. Of course, if a person's password settings are not regular or complex, not included in the password dictionary, this dictionary is useless, and even extend the time required for password cracking. There are crunch and Rtgen two tools in Linux that can be used to create a password dictionary. For user-friendly use, this section describes how to use the two tools.

1. Crunch Tools

Crunch is a tool for creating password dictionaries, which are commonly used for brute force cracking. Passwords generated using the crunch tool can be sent to a terminal, file, or another program.

The following describes the use of the crunch tool to create a password dictionary.

Use crunch to generate a dictionary. The following steps are shown below.

(1) Start the crunch command. The execution commands are shown below.

[email protected]:~# crunch

After executing the above command, the following information will be output:

 1  [Email protected]:/home$ crunch  2  Crunch version 3.6  3  4  Crunch can create a wordlist based on the criteria you specify.  The output from crunch can is sent to the screen, file  , or to another program.  5  6  usage:crunch <min> <max>< Span style= "COLOR: #000000" > [options]  7   where min and Max are numbers  8  9  Refer to the man  page for  instructions and examples on how to use crunch. 

The output information shows the version and syntax format of the crunch command. Where the syntax format for generating passwords using the crunch command is as follows:

crunch [minimum length] [maximum length] [character set] [options]

The common options for the crunch command are as follows.

• -O: Used to specify the location of the output dictionary file.
• -B: Specifies the maximum number of bytes to write to the file. The size can specify KB, MB, or GB, but must be used with the-O start option.
• -T: Sets the special format used.
• -L: This option is used to identify some characters of a placeholder when the-t option specifies @,%, or ^.

(2) Create a password list file and save it on the home directory. Where the minimum length of the generated password list is 4, the maximum length is 6, and 0123456789 is the character set. The execution commands are as follows:

1[Email protected]:~$ Crunch4 6 0123456789-Opasswd. txt2Crunch would now generate the following amount of data:7650000bytes3 7MB4 0GB5 0TB6 0PB7Crunch would now generate the following number of lines:1110000 8 9Crunch -% completed generating output

From the output above, you can see that the 7MB large file will be generated with a total of 1110000 rows. When the above command finishes executing, a dictionary file named Pass.txt is generated on the home directory. Because the combination generates more passwords, it takes a long time.

(3) After the password dictionary file is generated, view the first and the end of the generated password file. The execution commands are as follows:

1[Email protected]:~$Head passwd. txt2 00003 00014 00025 00036 00047 00058 00069 0007Ten 0008 One 0009 A[Email protected]:~$Tail  passwd. txt - 999990 - 999991 the 999992 - 999993 - 999994 - 999995 + 999996 - 999997 + 999998 A 999999

We can see that the generated dictionary files meet our requirements.

2. Rtgen Tools

The Rtgen tool is used to generate rainbow tables. The Rainbow table is a large collection of pre-computed hash values for a variety of possible combinations of letters. Rainbow table is not necessarily for the MD5 algorithm, a variety of algorithms have, with it can quickly crack various types of passwords. The more complex the password, the more rainbow tables are needed, and now the main rainbow table is more than 100G.

Use the Rtgen tool to generate a rainbow table. The procedure is as follows:

(1) switch to the Rtgen directory. The execution commands are shown below.

[email protected]:~# cd /usr/share/rainbowcrack/

(2) Use the Rtgen command to generate a rainbow table based on MD5. The execution commands are as follows:

[email protected]:/usr/share/rainbowcrack#./rtgen MD5 loweralpha-numeric 1 5 0 3800 33554432 0rainbow table Md5_low Eralpha-numeric#1-5_0_3800x33554432_0.rt Parametershash Algorithm:md5hash LENGTH:16CHARSET:ABCDEFGHIJKLMNOPQR Stuvwxyz0123456789charset in hex:61 30 31 32 3 6b 6c 6d 6e 6f All-in-all-in-a-6a 3 39charset length:36plaintext Length range:1-5reduce offset:0x00000000plaintext Total:62193780sequen Tial starting point begin from 0 (0x0000000000000000) generating ... 131072 of 33554432 Rainbow Chains generated (0 M 42.5 s) 262144 of 33554432 Rainbow Chains generated (0 M 39.2 s) 393216 of 33554432 Rainbow Chains generated (0 M 41.6 s) 524288 of 33554432 Rainbow Chains generated (0 M 42.0 s) 655360 of 33554432 R Ainbow chains generated (0 M 39.1 s) 786432 of 33554432 Rainbow Chains generated (0 M 40.1 s) 917504 of 33554432 Rainbow Cha Ins generated (0 M 39.9 s) 1048576 of 33554432 Rainbow Chains generated (0 M 38.8 s)1179648 of 33554432 Rainbow Chains generated (0 M 39.2 s) 1310720 of 33554432 Rainbow Chains generated (0 M 38.2 s) ..... 33161216 of 33554432 Rainbow Chains generated (0 M 40.2 s) 33292288 of 33554432 Rainbow Chains generated (0 M 38.9 s) 334233 33554432 Rainbow Chains generated (0 M 38.1 s) 33554432 of 33554432 Rainbow Chains generated (0 M 39.1 s)

The above information shows the parameters of the rainbow table and the generation process. For example, the generated Rainbow table file is named Md5_loweralpha-numeric#1-5_0_3800x33554432_0.rt, and the table is encrypted using the MD5 hash algorithm. ; The character set abcdefghijklmnopqrstuvwxyz0123456789 used and so on.

(3) To make it easy to use the generated rainbow table, use the Rtsort command to sort the table. The execution commands are as follows:

[email protected]:/usr/share/rainbowcrack# rtsort md5_loweralpha-numeric#1-5_0_3800x33554432_0.rtmd5_loweralpha-numeric#1-5_0_3800x33554432_0.rt:1351471104 bytes memory availableloading rainbow table…sorting rainbow table by end point…writing sorted rainbow table…

Outputting The above information indicates that the resulting rainbow table has been successfully sorted.

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Original link: http://www.cnblogs.com/student-programmer/p/6729015.html

Linux Dictionary Generation tool-crunch and Rtgen