Visit Our UNIX and Linux User Community


How to decrypt a file in UNIX?


 
Thread Tools Search this Thread
Top Forums UNIX for Advanced & Expert Users How to decrypt a file in UNIX?
# 15  
Old 08-28-2013
Quote:
Originally Posted by hergp
If you look closely, you'll find, that the working string S will never be longer than the longest line of the input file plus 63.
You are right. There is a kernel constant called "MAX_LIN" in "/usr/sys/include/limits.h". If the file has lines longer than this "awk"s read will fail because this limitation is built into all line oriented utilities, including "awk" (and "sed", "fmt", "sort", "vi", ...).

I mentioned it because many people are not even aware of this intrinsic limitation, which might have different values across platforms, but is everywhere in place.

I hope this helps.

bakunin

Previous Thread | Next Thread
Test Your Knowledge in Computers #732
Difficulty: Easy
In BASIC, GOTO jumps to a numbered or labelled line in the program.
True or False?

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers

Encrypt and Decrypt a File with Password

Hello, I have few files on unix which are payroll related and I need them to encrypt with password so others wouldn't see the data. I use ETL tool and would like to know the unix command that does encryption/decryption to use in the ETL. Thank you, Sri (3 Replies)
Discussion started by: eskay
3 Replies

2. Programming

Encrypt and Decrypt file using RIJNDAEL-128

Hi All, Can I use MCRYPT - (RIJNDAEL-128) / CBC mode to encrypt and decrypt a file? I am trying to find some sample C program on internet, which will encrypt and decrypt a file. But was not able to find any thing. Can some help me with the programming. Thanks. (1 Reply)
Discussion started by: Shre
1 Replies

3. UNIX for Dummies Questions & Answers

How to Unmask/Decrypt an XML file?

Hello All, Below is the content of the XML datafile when i do vi the XML file not sure why the content is showing like this, it could be because the data inside the file is masked or something? is there a way i can decrypt or unmask the data in a human readable format? . When i use my Informatica... (20 Replies)
Discussion started by: Ariean
20 Replies

4. UNIX for Dummies Questions & Answers

How to decrypt any file in UNIX?

How to decrypt a file in unix? I dont know the type of decryption nor the type of text data it contains. We extracted the file from sfdc & need to process it in unix. When extracted, we get encrypted data in the file. The file content is- ... (0 Replies)
Discussion started by: saga20
0 Replies

5. Shell Programming and Scripting

Need to decrypt a file in a directory (SHL script)

I need to decrypt a file in a directory, I need to write a shl scrip & cron job How I find the files in the directory: the file is like this: dailypayments_sfs_payment_201011151800.dat -d The decrypt command: gpg -o dailypayments_sfs_payment_201011151800.dat -d 20101115 (the date... (7 Replies)
Discussion started by: rechever
7 Replies

6. Shell Programming and Scripting

decrypt the file

Hello all I am getting a encrypted file (.pgp) and a key which i have to use to decrypt that file. I couldn't understand where to put the key on my unix box so that decryption happens. Please reply. (2 Replies)
Discussion started by: vasuarjula
2 Replies

7. Shell Programming and Scripting

How to encrypt and decrypt a file

How to encrypt and decrypt a file using unix Command? Can any one help me? (2 Replies)
Discussion started by: laknar
2 Replies

8. Solaris

Decrypt Des file - then encrypt

Help.. I need to decrypt a file that was encrypted using DES 56 Bit. I have the encryption key and the block size used but no idea what utility to use.. I then need to encrypt the file using pgp and another key I have.. againt I dont know what utility to use. I am running solaris 9 .... ... (0 Replies)
Discussion started by: frustrated1
0 Replies

9. Programming

decrypt function in unix?

Hai Friends We have a function called char * crypt(const char *ps, const char* key) to encrypt the password in the unix environment.. Do we have any decrypt function to decrypt it? If not then how can we verify the password through program? Thanks in Advance Collins (1 Reply)
Discussion started by: collins
1 Replies

10. Shell Programming and Scripting

How to decrypt a file which is encrypted in UNIX, In Windows NT

Hi, I want to encrypt a file in UNIX(HP-UX) and Transfer to a FTP server. Our FTP server is Windows NT. SO, how can i decrypt the file which is encrypted in UNIX, in Windows NT. Please, help me this is urgent. Siva Gorantla:confused: (3 Replies)
Discussion started by: gorantla
3 Replies
decrypt(3)						User Contributed Perl Documentation						decrypt(3)

NAME
Filter::decrypt - template for a decrypt source filter SYNOPSIS
use Filter::decrypt ; DESCRIPTION
This is a sample decrypting source filter. Although this is a fully functional source filter and it does implement a very simple decrypt algorithm, it is not intended to be used as it is supplied. Consider it to be a template which you can combine with a proper decryption algorithm to develop your own decryption filter. WARNING
It is important to note that a decryption filter can never provide complete security against attack. At some point the parser within Perl needs to be able to scan the original decrypted source. That means that at some stage fragments of the source will exist in a memory buffer. Also, with the introduction of the Perl Compiler backend modules, and the B::Deparse module in particular, using a Source Filter to hide source code is becoming an increasingly futile exercise. The best you can hope to achieve by decrypting your Perl source using a source filter is to make it unavailable to the casual user. Given that proviso, there are a number of things you can do to make life more difficult for the prospective cracker. 1. Strip the Perl binary to remove all symbols. 2. Build the decrypt extension using static linking. If the extension is provided as a dynamic module, there is nothing to stop someone from linking it at run time with a modified Perl binary. 3. Do not build Perl with "-DDEBUGGING". If you do then your source can be retrieved with the "-Dp" command line option. The sample filter contains logic to detect the "DEBUGGING" option. 4. Do not build Perl with C debugging support enabled. 5. Do not implement the decryption filter as a sub-process (like the cpp source filter). It is possible to peek into the pipe that connects to the sub-process. 6. Check that the Perl Compiler isn't being used. There is code in the BOOT: section of decrypt.xs that shows how to detect the presence of the Compiler. Make sure you include it in your module. Assuming you haven't taken any steps to spot when the compiler is in use and you have an encrypted Perl script called "myscript.pl", you can get access the source code inside it using the perl Compiler backend, like this perl -MO=Deparse myscript.pl Note that even if you have included the BOOT: test, it is still possible to use the Deparse module to get the source code for individual subroutines. 7. Do not use the decrypt filter as-is. The algorithm used in this filter has been purposefully left simple. If you feel that the source filtering mechanism is not secure enough you could try using the unexec/undump method. See the Perl FAQ for further details. AUTHOR
Paul Marquess DATE
19th December 1995 perl v5.16.3 2013-04-02 decrypt(3)

Featured Tech Videos