RE: Encryption/password protected excel/word files
I should mention that the exceptions don't really tell if the files are password protected or not. For word, I catch an ArrayIndexOutOfBoundsException, or java.lang.NegativeArraySizeException. I'm guessing that is not the expected behaviour. thanks -Original Message- From: Justin Warren Sent: Monday, April 16, 2007 2:49 PM To: poi-user@jakarta.apache.org Subject: Encryption/password protected excel/word files Hi all, I am trying to detect if a file is password protected before reading it (ie, if it is password protected, I want to ignore it). Right now, I am just catching exceptions that get thrown, but I was wondering if there was another way of doing this. Thanks - To unsubscribe, e-mail: [EMAIL PROTECTED] Mailing List: http://jakarta.apache.org/site/mail2.html#poi The Apache Jakarta Poi Project: http://jakarta.apache.org/poi/
Re: Encryption/password protected excel/word files
Guys lets stay away from encryption. We'd have to do all this registering with the government and a whole lot of hassle for not much benefit. Lame encryption to boot. Nick Burch wrote: On Tue, 17 Apr 2007, Justin Warren wrote: I should mention that the exceptions don't really tell if the files are password protected or not. For word, I catch an ArrayIndexOutOfBoundsException, or java.lang.NegativeArraySizeException. I'm guessing that is not the expected behaviour. With powerpoint, we did find one record we could look for early on that indicates if the file is encrypted or not. For the others, we haven't spotted anything suitable. The problem is that if the file is encrypted, lots of the core records are there, but there data is encrytped, and hence garbage if you try to read it as if it wasn't. Unless we can tell very early on that a file is encrypted, we can't just look through the record list looking for the encrypted record flag, since the parent records can't be read properly. Instead, we must find either a absolute offset to an indicator, or one non encrypted record at a given location that'll have a child that tells you it's encrypted. If someone encrypts both the properties and the document, it's easy, as you can tell at the poifs level. If they just encrypt the document, it's hard. See EncryptedSlideShow in hslf for an example of how to do it for powerpoint. Any suggestions for a similar way to do it for word or excel gratefully received :) Nick - To unsubscribe, e-mail: [EMAIL PROTECTED] Mailing List: http://jakarta.apache.org/site/mail2.html#poi The Apache Jakarta Poi Project: http://jakarta.apache.org/poi/ -- From Windows/Exchange to Linux/Meldware Buni Meldware Communication Suite Email, Calendaring, ease of configuration/administration http://buni.org - To unsubscribe, e-mail: [EMAIL PROTECTED] Mailing List: http://jakarta.apache.org/site/mail2.html#poi The Apache Jakarta Poi Project: http://jakarta.apache.org/poi/
Re: Encryption/password protected excel/word files
Andrew C. Oliver schrieb: Guys lets stay away from encryption. We'd have to do all this registering with the government and a whole lot of hassle for not much benefit. Lame encryption to boot. This depends. We here in Europe or at least here in Germany don't have to do any registering with the government for encryption/decryption. Best regards Rainer Klute Rainer Klute IT-Consulting Dipl.-Inform. Rainer Klute E-Mail: [EMAIL PROTECTED] Körner Grund 24 Telefon: +49 172 2324824 D-44143 Dortmund Telefax: +49 231 5349423 OpenPGP fingerprint: E4E4386515EE0BED5C162FBB5343461584B5A42E signature.asc Description: OpenPGP digital signature
Re: Encryption/password protected excel/word files
Since the apache servers are in the United States, and the Apache Foundation is a US not for profit corporation, all projects are required to meet US Export regulations with regard to encryption technology. See http://www.apache.org/licenses/exports/ Regards, Dave On Apr 17, 2007, at 12:10 PM, Rainer Klute wrote: Andrew C. Oliver schrieb: Guys lets stay away from encryption. We'd have to do all this registering with the government and a whole lot of hassle for not much benefit. Lame encryption to boot. This depends. We here in Europe or at least here in Germany don't have to do any registering with the government for encryption/decryption. Best regards Rainer Klute Rainer Klute IT-Consulting Dipl.-Inform. Rainer Klute E-Mail: [EMAIL PROTECTED] Körner Grund 24 Telefon: +49 172 2324824 D-44143 Dortmund Telefax: +49 231 5349423 OpenPGP fingerprint: E4E4386515EE0BED5C162FBB5343461584B5A42E - To unsubscribe, e-mail: [EMAIL PROTECTED] Mailing List: http://jakarta.apache.org/site/mail2.html#poi The Apache Jakarta Poi Project: http://jakarta.apache.org/poi/
