ZIP·RAR·7z·tar 압축 포맷 한눈에 이해하기

The two jobs of an archive

An archive does two separate things: it bundles many files and folders into one, and it shrinks the data. ZIP and 7z do both at once, while tar only bundles and leaves shrinking to a separate compressor such as gzip, xz or zstd, which is why Linux files carry double extensions like .tar.gz. Knowing this lets you guess what an unfamiliar extension does.

In practice the problem is rarely the compression ratio. It is whether the recipient can open the file, whether Korean file names survive, and whether the recipient's tool supports the encryption you chose. This guide tabulates the formats, then covers encryption and cross-platform traps separately.

Format comparison

A spec ceiling such as 7z's 16000000000 GB is not a practical limit. The real limits are the file system, free disk space and the recipient's tool. A ZIP over 4 GB needs a tool that understands ZIP64, which is a frequent problem with older software.

Encryption: ZipCrypto, AES and file names

Compression shrinks; encryption hides. They are configured on one screen but are independent: a password does not make a file smaller, and compressing does not make it safe. Three points matter.

1) ZipCrypto and AES are different

The PKWARE APPNOTE (section 6.0.1) describes traditional ZIP encryption as "considered weak by today's standards" and recommends it only for low-security needs or compatibility with old ZIP software. Section 7.0 defines strong encryption with ciphers including AES [1]. Many tools just say "set password", so you may silently get the old method. For anything important, choose AES-256 explicitly. The cost is compatibility: some older tools cannot open AES ZIPs, so confirm the recipient can.

2) A password may not hide file names

A password-protected ZIP often still shows its file list. If names reveal content, information leaks. In 7-Zip, turning on file-name (header) encryption for a 7z hides the list until the password is entered. If names are sensitive, use that option, or bundle into one neutrally named file before encrypting.

3) A weak password defeats any algorithm

AES-256 with "1234" is pointless. 7z derives its key through repeated SHA-256 hashing to slow brute force [2], but that cannot rescue a weak password. Use a long, hard-to-guess phrase and send it through a different channel than the archive.

Cross-platform pitfalls

Garbled Korean file names

The most common problem. The ZIP spec's default file-name character set is IBM Code Page 437, and names are read as UTF-8 only when general-purpose bit 11 is set [1]. Archivers on Korean Windows that do not set the bit often store names in the system code page (CP949, Microsoft identifier 949) [5]. Opening that ZIP in a tool that assumes UTF-8 produces gibberish; the reverse also garbles names in old Windows tools that read UTF-8 as a local code page.

Fix it on both ends. As a receiver, use a tool that detects or lets you choose the encoding (CP949 versus UTF-8). As a sender, use a "Windows-compatible names" option if your tool has one, or use formats such as 7z or tar that store Unicode names. File contents are intact; only names are misread, so restoring names is enough. The Zipda section below shows this on screen.

Metadata macOS adds

A ZIP made on a Mac may show __MACOSX, .DS_Store and ._filename helper files when opened on Windows. They hold resource forks, extended attributes and folder view settings; they are hidden on macOS and look like clutter elsewhere. Deleting them does not damage your data. When sending to Windows or Linux users, use a tool or option that leaves them out. Another Mac-originated quirk is Korean letters shown split into separate jamo, caused by a different Unicode normalization form. That is a name representation issue, not corruption.

Already-compressed data does not shrink

JPG, MP4, existing ZIPs and images inside PDFs barely shrink. Bundling a photo folder is for sending one object, not for saving space; recompressing only costs time.

Large files and split archives

Mail or messenger limits sometimes force splitting. Naming differs: 7z and ZIP use numbered parts such as .7z.001 and .zip.001, or .z01, .z02 followed by .zip; RAR uses .part1.rar. The ZIP spec itself allows spanning multiple volumes or user-defined segment sizes [1].

1. Keep every part in one folder; a missing part blocks extraction.
2. Do not rename parts; tools find the set by naming pattern.
3. Open the first part (.001, .part1.rar, or the final .zip) and the rest follow.
4. Compare part sizes with the sender's. "Corrupted archive" usually means an interrupted download or a missing part.

Splitting is convenient, but losing one part loses everything. Often a different sharing route is better; see moving files between devices for alternatives by size limit.

Choosing a format

The deciding factor is who receives it. When unsure, ZIP. When size matters and the recipient has a tool, 7z. For Linux or developer environments, tar family. For hidden file names, 7z with header encryption. The chooser in the Korean section above (interactive tool, Korean UI) asks about your goal, the recipient and whether you need splitting, then lists candidates with reasons.

On a phone: Zipda

The iPhone Files app can create and extract ZIPs, but RAR, 7z, encrypted archives and encoding problems are beyond the built-in feature. Zipda, an iOS and macOS app I develop, targets those cases. This is the only section about it; everything above applies regardless of app. From the developer documentation and store screenshots:

• Creates and extracts ZIP, 7z and tar variants (tar, tar.gz, tar.bz2, tar.xz); extracts RAR, LZH and ALZ only. No EGG support because of licensing and patent issues, and no RAR creation.
• Opens password-protected ZIP, 7z and RAR, and is designed to handle ZipCrypto. When creating, ZIP can use AES-256.
• Detects file-name encodings on the device and has a repair tool for garbled names. The developer docs note a limitation: very short Japanese names can be misread as Korean, so try another encoding if results look wrong.
• Opens files over 4 GB (ZIP64) and split sets. Creating split archives is outside this guide.
• Free, with extraction and creation each capped at 3 per 24 hours; browsing, search, preview and file-name repair do not count. A subscription removes the cap; see the store for pricing.

The screenshots in the Korean section show the name list, name repair with CP949, the password prompt, large-file progress, the create screen with a Windows-compatible names option, and the home screen with the remaining daily count.

Who it suits and who it does not

More in the Zipda guide. Whatever app you use, decide whether an archive from an unknown source is trustworthy before extracting it.

Troubleshooting

Sources

Same URLs as the Korean list above: PKWARE ZIP APPNOTE 6.3.9 [1] (ZIP64 4.5.3, spanning 4.3.3, encryption 6.0.1 and 7.0, language encoding appendix D), 7-Zip 7z format page [2], RARLAB WinRAR changelog [3], Zstandard site [4], Microsoft Learn code page identifiers [5]. Not verified, so no figure given: RAR maximum file size and AES details, tar size limits, and per-version format support in the macOS and Windows built-in tools.

FAQ