Compression and encryption - Table of Contents

Compression and encryption overview

With CS Browser you may automatically compress and/or encrypt files before uploading them to Amazon S3 and automatically decompress and/or decrypt them after downloading.

The ZIP format is used for data compression and AES 256 symmetric algorithm for data encryption, allowing you to decompress/decrypt files with any 3-rd party archive manager.

The GZip format is also supported for cases when you need to serve compressed files over the Internet.

You may also decompress and/or decrypt files automatically when downloading them using CS Browser. If password is not found on the local computer, you will be asked to enter it before downloading the file(s).

Compression and encryption can be easily configured using flexibe set of rules. You may configure rules on bucket, folder or file level.

The rules are stored locally in CS Browser settings folder. If you define the rules on a Machine A and then upload the file from the Machine B, the rules are not applied. You may transfer rules to another computer, they are located in the %APPDATA%\S3Browser folder in the file named bucket.rules.

Below you will find detailed description of compression and encryption rules.

Managing compression and encryption rules

To open Compression and Encryption rules manager:

Click Tools > Compression and Encryption

The Compression and Encryption Rules dialog will open:

To add new Compression/Encryption rule

1. Click the Add button (or press the Ins keyboard shortcut).

   The Add New Compression/Encryption Rule dialog will open:

   

2. Fill out the following optional fields:

   Bucket name or mask: - Identifying one or more buckets to which the rule applies. Empty bucket name means all buckets.

   Remote file name or mask: - Identifying one or more files to which the rule applies (e.g. docs/* or *.xls). Empty file name means all files.

   Check Compress files before uploading checkbox to compress files before uploading them to Amazon S3.

   Choose the Compression method: Zip (for regular uploads) or GZip (for files distributed over the Internet)

   You may also adjust Compression level. Better compression takes more time and CPU/RAM, lower compression is faster and requires less resources.

   Avoid enabling compression for already compressed files such as jpg, gif, png images, compressed video files, archives (zip, rar, 7z, etc.). Be also careful when enabling compression for very large files, this may take a lot of time and CPU resources.

   Check Encrypt files before uploading checkbox and specify Encryption password if you would like to encrypt files before uploading them to Amazon S3.

   Compression/Encryption rules are stored in plain form, so you may want to delete them when upload is finished.

   You may also temporarily enable/disable the rule using corresponding check-box.

3. Click Add new rule to close the dialog.

4. Click Save changes to save changes and close rules manager.

To edit Compression/Encryption rule

1. Select the rule you want to edit and click the Edit button

   The Edit Compression/Encryption rule dialog will open:

   

2. Edit rule details and click Save Changes

3. Click Save changes to close rules manager and save changes

To delete Compression/Encryption rule(s)

1. Select one or more rules you want to delete and click Delete

   

2. Click Save changes to close rules manager and save changes

Downloading compressed/encrypted file(s)

If you download compressed file with CS Browser, the file decompressed automatically when download is finished.

If file is encrypted, CS Browser looks into compression/encryption rules and if corresponding encryption rule is found, the password is taken from the rule to decrypt the file.

If no matching rule is found, you will be asked to enter decryption password:

The following options are available:

Enter decryption password - you may enter decryption password for the file

Download encrypted file 'as is' - decryption is not performed, the file is downloaded in encrypted form.

Do not download this file - the file will be skipped

You may also tick the Remember my choice for other files in the queue checkbox to apply your choice for other files in the queue.

If the password you specified is not valid, you will see the following dialog:

The following options are available:

Enter decryption password - you may re-enter decryption password for the file

Do not decrypted this file - decryption is skipped, the file is downloaded in encrypted form.

Decompressing/Decrypting files without CS Browser

When CS Browser applies Zip compression or encryption, it processes each file individually. It does not combine multiple files into one archive. The file keeps its original name and extension in Amazon S3.

For example, document.txt remains document.txt, although its contents are a Zip archive. 7-Zip detects the archive by its contents, so you can extract the file without renaming it.

If you download compressed or encrypted files using another tool or an older version of CS Browser, you can decompress or decrypt them with a compatible third-party archive manager.

You may use free open-source archiver 7-zip:

1. Open the folder containing the downloaded files in 7-Zip File Manager, select one or more compressed or encrypted files, and click Extract.

   

2. Choose the destination folder. If the files are encrypted, enter the decryption password, and then click OK.