Archive files with multiple encryption passwords

How to create archives with multiple passwords

Most of mainstream archive formats standards (including 7Z, RAR, and ZIP / ZIPX) provides file-level encryption scheme.
That architecture choice means a single archive can be created to contain files encrypted with different passwords - ideally a different password for each file can be applied.
This basically allows a single archive to contain distinct files encrypted with distinct passwords: it is possible to use more than a single password in the same archive encrypting each file witha different password.
Also, this allows a single archive to contain both encrypted and non encrypted content, chosing to apply or not to apply password in each creation / update operation.

Updating existing archives let user set (or omit) an arbitrary password at each instance, allowing to (potentially) protect each group of files with a different password.

Encrypted archives formats write- supported by PeaZip

PeaZip supports creating and updating encrypted files under following standards implementing file-level selective encryption:

create 7Z files with 7-Zip / p7zip AES256-based encryption
create ARC files with FreeArc AES256, Twofish256, Serpent256, and Blowfish algorithm
create RAR files as RAR4 with AES128, and as RAR5 with AES256
create ZIP files / create ZIPX files with WinZip AES256-based AE (Advanced Encryption), and ZipCrypto (legacy)

PEA format supports only archive-level encryption so allows / guarantee a single password being set when the archive is created - which may be an advantage or disadvantage depending on the user's needs.

How to extract archives with multiple passwords

Extracting data from encrypted archives requires the correct password being provided to the decryption procedure, otherwise protected data will result unreadable and extraction procedure will fail.

Consequently, when working with archives whose content is selectively protected by different passwords for different groups of files, it is needed to extract each group of archived file with its own password, in separate passes.

Encrypted archive formats read- supported by PeaZip

PeaZip supports, for extraction / decrypting, all the previously mentioned formats (read/write supported) plus following read-only supported archive types:

extract ACE files with WinAce Blowfish-based encryption
extract RAR files: RAR4 with AES-128 encryption, and RAR5 with AES-256 in CBC mode
extract ZIP files with PKZip's AES encryption standard (format is fully supported, but encryption routine is read-only supported)
extract ZIPX files with WinZip's AE, based on AES-256 (encryption routine is fully supported, but format is read-only supported)

Current revision of PEA specifications supports a single password for the entire archive, so archives with multiple passwords does not exists in PEA format.

Archives protected by multiple encryption layers

An different case of multi-password archive is when one or more existing password-protected archives are added to a new password protected archive container, and (potentially) so on, so a different password is added at each archive creation / update iteration.
This basically means a single archive which is entirely encrypted multiple times with multiple passwords.
This may be preformed in order to have different passwords and/or different types of cryptography to be applied to protect the content at each layer, but comes at cost of requiring multiple archiving iterations to build such archive - and obviously to equally require multiple extraction iterations, until the actual plain-text content is reached.
Since iterations will be performed sequentially, there is no technical difficulty for any archiving utility to handle this case of double ot triple or multiple password layers, providing appropriate password at each serial archiving / extraction iteration step.

PEA archive format supports triple cascade encryption, combining AES, Twofish, and Serpent algorithms each with 256 bit key, used in EAX mode.

Learn more about how to hide content of archive encrypting file names (possiblòe for 7Z, ARC, and RAR files, but not for ZIP files), and how to open encrypted files.

Synopsis: How to create, update, open, extract 7Z, ACE, ARC, RAR, ZIP files protected by multiple passwords for distinct files in the same archive. Set multi password protection: add, apply multiple encryption layers to a single archive.

Topics: archives encrypted with multiple passwords

PeaZip > FAQ > Archive files with multiple encryption passwords