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Summary

"AttachéCase" is puts emphasis on a daily use, and focusing on simplicity of appearance and easy operability, but it is powerful file encryption software adopting world standard encryption algorithm.

Just by dragging and dropping a file and entering a password, it can be easily encrypted. When dragging and dropping each folder, it creates an encrypted file in one file (packs each folder).

暗号化の流れ

Since encrypted data is compressed, the size of the file becomes compact.

Just by dragging and dropping encrypted data or by double-clicking it and entering a password, you can easily return to the original file or folder.

Since it can also be output as an executable (*. exe) file, you can pass an encrypted file to someone who does not have an AttachéCase and they can decrypt it.

Abundant operation settings

各種動作設定ウィンドウ

Designation of save location, complete file deletion after processing, different password storage for each encryption / decryption, Adjustment of compression ratio, restriction by password input frequency, destroying encrypted data, etc., command line option are also available.

These makes it possible to manipulate and process files / folders associated with encryption / decryption with fine designation.

Adopted world standard encryption algorithm

Adopted "Rijndael" selected as the next generation encryption standard AES (Advanced Encryption Standard) in October 2000 by NIST ( http://csrc.nist.gov/ ). In AES, the block length is fixed at 128 bits, but AttachéCase adopts the specification of Rijndael, and the key and the block length are also 256 bits.

In addition, it is devised to prevent analysis by a malicious attacker by encrypting it in CBC mode after generating initialization vector (IV) by random number. ( For details, please refer to the "About encryption algorithm" page )

"Attache Case" has been open source since July 2012, licensing has also been changed. For details, please see "License" page.

Operating environment

You can use it with Windows XP / Vista / 7 / 8 / 10

However, .NET Framework 4 is required for the operation. It must be installed on Windows XP, Vista, 7.
For Windows 8, 10, you do not need to install anything (installed by default).

As for Windows XP, I think that it will work, since support of Microsoft is terminated, I will make it out of support.

Setup

Install

  • When installing from installer ( atcs****.exe )
    Double click "atcs ****. Exe" as it is and follow the instructions of the setup wizard to install it. I think that it is almost never set by you.
  • When installing from Zip file ( atcs****.zip )
    Overwrite all files to the folder that was used before. When the folder changes, the extension association setting etc. become invalid. If you want to change the folder, please remove the old AttachéCase once again by the method of the next paragraph and install it again.


Uninstall

  • When installed from installer ( atcs****.exe )
    Select "AttachéCase" from "Programs and Functions" of "Control Panel" (Windows XP etc. from "Add / Remove Programs") and delete it. However, if you want to cancel the association setting with the extension (* .atc), please refer to the following "How to disassociate" before doing.
  • When installed from Zip file ( atcs****.zip )
    Please delete each folder with the AttachéCase.
    However, if you want to cancel the association setting with the extension (* .atc), please refer to the following "How to disassociate" before doing.。


How to disassociate

If you want to cancel the association setting to * .atc file, launch "AttachéCase", select "Settings" -> "System", and then push "Disassociate encrypted file(*.atc) with AttachéCase" button. The association settings are deleted from the system.

For Windows Vista / 7 / 8 / 10, you will be asked for elevating administrators when setting.

If you perform the uninstaller or the above method, the registry information will be deleted. If you want manual deletion for some reason, delete the following registry.

HKEY_CURRENT_USER\Software\Hibara\AttacheCase

When manually operating registry, sufficient knowledge and caution are necessary. Please go only if you are confident. Even if some kind of failure occurs in the system due to incorrect registry operation, I can not assume the responsibility. Even if the registry remains, there will be no problem with future operation. Let's stop those who do not have confidence.

Limitations

If your operating system (OS) is 32 bit version, the self-executable output will be limited to 4 GB or less. This is due to the limitation that 32 bit OS will only recognize memory up to 4 GB.

In the AttachéCase, you can output an executable file of 4 GB or more, but you can not run it on the 32 bit OS.

However, if you drag and drop the executable file directly to the AttachéCase, you can decrypt it without problems.

If you forget your password

It will not do anything. Please give up. :)

I often get an e-mail about it, but even the author can not decrypt it. The password character string is not included as it is in the encrypted file as a key, but it is used as a shuffling "source" when encrypting it. As the image is the same as "seasoning" put in cooking, it is in a state of being completely melted and mixed with the soup.

Therefore, once you forget your password, it will be impossible to extract passwords or restore from mixed files. The high cryptographic strength has been proved, and it is impossible for the author to decrypt it.

If it is encryption software that someone can decrypt it, does not it make sense??

However, there may still be some people who want to decrypt it somehow. Below are a few ways, but I will give you some examples.


Brute force script from the command line

In the AttachéCase, you can use command line options, so you would solve it by a brute force attack by programing scripts and batch files. If you have some knowledge of the program, you will be able to program it immediately.


Develop crack tool from open source

"AttachéCase" is now open source, so there is also a last resort to develop brute force crack tool by yourself.


Is it faster to recall your password?

After all, these have limitations as well. If the number of entered password characters is large, the number of combinations will increase. It will be awfully long to decrypt. It might be that it is much more efficient to recall the password you forgot, and the probability of decryption is high.

Conversely, on the premise that password management is done properly, in order to create an encrypted file hard to be broken by an attacker, it is necessary to input the password in consideration so that it can endure the "Brute force script" attack. You should devise various ways, such as entering long strings, using the password file function.


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