Encryption or Search and Replace?

acron5 has asked for the wisdom of the Perl Monks concerning the following question:

I need your assistance and suggestions..... I need to write a perl application that takes a text file that is FTP'd from one server to another server through an automated batch process and decrypt the contents and save as another text file. Decryption is a simple replace 1 with a , replace b with g etc. We have a table of values and what we are changing them to. Also I need this to not change a letter/number once it has already been changed. I hope that made sense. Any help would be greatly appreciated. Please keep in mind that I am fairly new to Perl.

Comment on Encryption or Search and Replace?

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Re: Encryption or Search and Replace? by Albannach (Monsignor) on May 16, 2001 at 21:26 UTC
For the "decryption" you will want tr. A couple of comments are in order: If this is for your work, you should be aware that a simple substitution is an extremely easy code to break, so you are not providing much security at all by this mechanism. If this is for a homework assignment, you will probably find the monks more helpful if you state that up front, and demonstrate some effort at solving the problem yourself. -- I'd like to be able to assign to an luser	[reply]
Re: Encryption or Search and Replace? by Beatnik (Parson) on May 16, 2001 at 21:18 UTC
check Net::FTP for the FTP stuff... Greetz Beatnik ... Quidquid perl dictum sit, altum viditur.	[reply]
Re: Encryption or Search and Replace? by Sifmole (Chaplain) on May 16, 2001 at 21:29 UTC
I don't think the question is actually about how to facilitate the transfer, but more about how to implement the "decoding". acron5, you should probably investigate the use of regular expressions (s/blah/foo/) or translation operator (tr/1-9/a-i/). The look at looping to see how one can iterate over the contents of an entire file. Then if you read closely about regular expressions and reading data from a file you will realize that you don't need to iterate and can do it all with one regular expression or translation.	[reply]
Re: Re: Encryption or Search and Replace? by acron5 (Initiate) on May 16, 2001 at 23:24 UTC
Thank you, I think this is the right direction.	[reply]
Re: Encryption or Search and Replace? by converter (Priest) on May 16, 2001 at 23:24 UTC
Grab a copy of Convert::EBCDIC and look at the way it implements the ASCII to EBCDIC translation tables. That will probably give you a couple good ideas.	[reply]