Decrypt Password Encrypted Rar File
I have a PGP file named 'filename.txt.pgp' that I need to decrypt. When I run decryption from command-line it asks me only for the password. I use gpg command:
How to Decrypt RAR Files. RAR is a type of file format that has the capability of storing a number of files in a compressed state, therefore taking up less space on a storage device. RAR files can be encrypted by using the Windows Encrypting File System (EFS) to make them more secure. You can also use the Windows Encrypting File System. In this case, firstly try to unlock the encrypted RAR file by the following 2 means. Double click your password encrypted RAR file. Then double click to expand the folders saved in it. Maybe you can find the password there. Try to use the website where you downloaded the encrypted RAR file. The Decrypt Dialog. Choose Encrypt from the Actions menu of the WinZip Legacy Toolbar. When you are encrypting all files in a Zip file (.zip or.zipx ), WinZip needs to decrypt and then re-encrypt any files that are already encrypted. If a file cannot be decrypted using the encryption password you have specified.
There is no formula or backdoor (as far as I know), to decrypt a password-protected RAR file by doing miraculous tricks. By encrypting the information, the original bytes have been transformed by a mathematical algorithm using the password characters as an input. Let’s review all possible options you have!
Archive password recovery tool promises to decrypt WinRAR file password successfully and free recover password if it is no more than 3 characters. Online method would try best to recover RAR/ZIP password first and then ask for payment. Actually, RAR files behave almost the same way, except that they give you the option encrypt the file list. You can add fake files to a RAR file (not through WinRAR), but if the list of files is encrypted, then you cannot modify it, therefor the application opening it won't be able to list the fake file.
The password is enough and my file is decrypted. I can read it's content.
Now, I should create an utility in Java. After research I see that Bouncy Castle library is my best choice. But all the examples in Java I can find use public/private key file which I do not have.
Could you please help me with an example in Java that decrypts PGP file using just a password?
Thank you.
1 Answer
If you look at the documentation section of Bouncy Castle's site, they say to '...look at the test programs in the packages...' and they're not joking.
If you look inside the jar file from Bouncy Castle you will see under the org.bouncycastleopenpgpexamples directory a class file called 'PBEFileProcessor' that will cover password based encryption when using their library.
Here's a link to the same file in their Github repo.
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Do you wonder how vulnerable password-protected word-processing, spreadsheet, and Zip files are when users send them into the wild blue yonder? Wonder no more. Some great utilities can show how easily passwords are cracked. But there are some countermeasures you can take as well. Read on to learn more about both.
How to crack files
Most password-protected files can be cracked in seconds or minutes. You can demonstrate this “wow factor” security vulnerability to users and management. Here’s a hypothetical scenario that could occur in the real world:
Your CFO wants to send some confidential financial information in an Excel spreadsheet to a company board member.
She protects the spreadsheet by assigning it a password during the file-save process in Excel.
For good measure, she uses WinZip to compress the file and adds another password to make it really secure.
The CFO sends the spreadsheet as an e-mail attachment, assuming that the e-mail will reach its destination.
The financial advisor’s network has content filtering, which monitors incoming e-mails for keywords and file attachments. Unfortunately, the financial advisory firm’s network administrator is looking in the content-filtering system to see what’s coming in.
This rogue network administrator finds the e-mail with the confidential attachment, saves the attachment, and realizes that it’s password protected.
The network administrator remembers a great password-cracking tool available from Elcomsoft called Advanced Archive Password Recovery that can help him out so he proceeds to use it to crack the password.
Cracking password-protected files is as simple as that! Now all that the rogue network administrator must do is forward the confidential spreadsheet to his buddies or to the company’s competitors.
If you carefully select the right options in Advanced Archive Password Recovery, you can drastically shorten your testing time. For example, if you know that a password is not over five characters long or is lowercase letters only, you can cut the cracking time in half.
You should perform these file-password-cracking tests on files that you capture with a content filtering or network analysis tool. This is a good way to determine whether your users are adhering to policy and using adequate passwords to protect sensitive information they’re sending.
How To Open Encrypted Rar File
Countermeasures
The best defense against weak file password protection is to require your users to use a stronger form of file protection, such as PGP, or the AES encryption that’s built in to WinZip, when necessary.
Ideally, you don’t want to rely on users to make decisions about what they should use to secure sensitive information, but it’s better than nothing. Stress that a file encryption mechanism, such as a password-protected Zip file, is secure only if users keep their passwords confidential and never transmit or store them in unsecure cleartext (such as in a separate e-mail).
How To Open Password Encrypted Rar File
If you’re concerned about unsecure transmissions through e-mail, consider using a content-filtering system or a data leak–prevention system to block all outbound e-mail attachments that aren’t protected on your e-mail server.