ONE APP · EVERY ARCHIVE
Starkive opens and extracts ZIP, 7Z, RAR, TAR, GZIP, BZIP2, and XZ. For encryption it uses the AES-256 Secure Container (.ssz), age, and OpenPGP, password-protects a ZIP for compatibility, and compresses to 7Z, TAR, GZIP, or BZIP2. Here is what the headline encryption formats are, where they came from, and how they protect your data.
The universal archive. Optional password for compatibility. Opens on every computer.
History
ZIP was created by Phil Katz of PKWARE in 1989 and published as an open specification, which is why it became the default archive format on practically every operating system. It also carries the most widely supported password scheme, ZipCrypto, which any ZIP tool can open.
Architecture
Files are compressed with the DEFLATE algorithm and stored with a central directory index. When you set a password, Starkive protects the ZIP with classic ZipCrypto so it stays compatible with Windows Explorer and any ZIP tool. ZipCrypto is the legacy scheme and is not strong encryption, so for real confidentiality use the AES-256 Secure Container (.ssz), age, or OpenPGP below.
Maximum compression. Smaller files than ZIP.
History
7-Zip was written by Igor Pavlov and first released in 1999. Its compression engine, the LZMA SDK, was placed in the public domain, so anyone can implement it. It became popular because it routinely produces noticeably smaller archives than ZIP.
Architecture
7-Zip uses the LZMA and LZMA2 algorithms, which combine a large dictionary with range coding to squeeze files harder than DEFLATE. Starkive emits .7z when you want the smallest possible output. It is a compression format with no password, so when you need encryption use the AES-256 Secure Container (.ssz), age, or OpenPGP below.
A small, modern format whose only job is to encrypt and decrypt a file.
History
age was designed by Filippo Valsorda, then the cryptography lead for the Go language, and released around 2019. It was a deliberate reaction to the complexity of PGP: a single-purpose tool with no key management, no metadata, and no configuration knobs. The format specification is short enough to read in one sitting.
Architecture
With a passphrase, age runs it through the scrypt key-derivation function to produce a wrapping key, which protects a random per-file key. The file body is encrypted as a ChaCha20-Poly1305 STREAM, split into 64 KiB authenticated chunks, so tampering with any part is detected. The result is a tiny, opaque file that reveals no metadata.
The long-standing open standard for encrypted files and email.
History
Phil Zimmermann wrote PGP (Pretty Good Privacy) in 1991. It was later standardized as OpenPGP (RFC 4880, updated by RFC 9580), and GnuPG became its free, widely-used implementation. Decades of interoperability mean a PGP file you create can be opened almost anywhere.
Architecture
Starkive uses OpenPGP in passphrase (symmetric) mode: your password derives an AES-256 session key via OpenPGP's salted key-derivation, the payload is compressed and encrypted, and a modification-detection code guards against tampering. The output is a standard .gpg file.
Starkive's own encrypted container that tells you the moment it is opened.
History
The Starkive Secure Container is our own format, built specifically for encrypted delivery with proof of receipt. Unlike the others, it is not just about confidentiality: it is designed so the sender learns when the file was first opened, and receives a signed PDF certificate.
Architecture
An .ssz file is a custom binary container: a fixed header holds a format identifier, version, a unique file token, a random salt, a SHA-256 integrity hash, and the payload length, followed by an AES-256 encrypted payload. The key is derived from your passphrase with PBKDF2-SHA256 at 310,000 iterations. When opened, the file token pings Starkive (no IP address stored) to trigger your notification.
The cards above cover the headline encryption formats. Here is the full archive support.
Open and extract
ZIP, 7Z, RAR (open only, never created), TAR, GZIP, BZIP2, and XZ, plus Starkive's own .ssz and .gpg / .age. Look inside any of them before extracting: see the file list, preview images without extracting, and pull out a single file, a selection, or a whole batch of archives at once.
Create and protect
For strong encryption, create the AES-256 Secure Container (.ssz), or .age and .gpg for interoperable encryption. Password-protect a ZIP with classic ZipCrypto when you need it to open anywhere, and compress to 7Z, TAR, GZIP, or BZIP2. There is no RAR creation, by design: RAR is a proprietary format Starkive can read but does not write.
PART OF STARKIVE
Open, extract, encrypt, and decrypt every supported format in Starkive on Windows. Free to download.