Random-access archive for Unix use

Answer 1

zip (you can use http://www.info-zip.org/ ) stores file attributes - please see Wiki

Each entry is introduced by a local header with information about the file such as the comment, file size and file name, followed by optional "Extra" data fields, and then the possibly compressed, possibly encrypted file data. The "Extra" data fields are the key to the extensibility of the ZIP format. "Extra" fields are exploited to support the ZIP64 format, WinZip-compatible AES encryption, file attributes, and higher-resolution NTFS or Unix file timestamps. Other extensions are possible via the "Extra" field. ZIP tools are required by the specification to ignore Extra fields they do not recognize.

Answer 2

You can check duplicty. It allow you to make compressed and encrypted backup and allows random access to file. Here you can find more info about these project: http://duplicity.nongnu.org/new_format.html.

If you want use it you can also check script duply. Is is shell front end for duplicty. More info: http://sourceforge.net/projects/ftplicity/