Skip to content

bzip2compressed archive (.bz2)

.bz2 file signature | application/x-bzip2

Bzip2 is a lossless data compression format created by Julian Seward and maintained as an open-source project. It is commonly used to compress individual files for distribution, software archives, backups, and Unix and Linux command-line workflows. The format is generally safe, but decompression of untrusted files can still consume significant memory or CPU resources; it is also older than some newer compression formats.

Safe

Magic Bytes

Offset 0
42 5A 68

Sources: Wikipedia, Gary Kessler

Extension

.bz2

MIME Type

application/x-bzip2

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .bz2 files in Python

Python 
def is_bz2(file_path: str) -> bool:
    """Check if file is a valid BZ2 by magic bytes."""
    signature = bytes([0x42, 0x5A, 0x68])
    with open(file_path, "rb") as f:
        return f.read(3) == signature

How to validate .bz2 files in Node.js

Node.js 
function isBZ2(buffer: Buffer): boolean {
  const signature = Buffer.from([0x42, 0x5A, 0x68]);
  return buffer.subarray(0, 3).equals(signature);
}

How to validate .bz2 files in Go

Go 
func IsBZ2(data []byte) bool {
    signature := []byte{0x42, 0x5A, 0x68}
    if len(data) < 3 {
        return false
    }
    return bytes.Equal(data[:3], signature)
}

API Endpoint

GET /api/v1/bz2
curl https://filesignature.org/api/v1/bz2

See the full API documentation for all endpoints and parameters.

Related Formats

.7z .arj .bz .cab .cpio .gz

Frequently Asked Questions

What is a .bz2 file?

A .bz2 file is a bzip2compressed archive file. Bzip2 is a lossless data compression format created by Julian Seward and maintained as an open-source project. It is commonly used to compress individual files for distribution, software archives, backups, and Unix and Linux command-line workflows. The format is generally safe, but decompression of untrusted files can still consume significant memory or CPU resources; it is also older than some newer compression formats.

What are the magic bytes for .bz2 files?

The magic bytes for bzip2compressed archive files are 42 5A 68 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .bz2 file?

To validate a .bz2 file, read the first bytes of the file and compare them against the known magic bytes (42 5A 68) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .bz2 files?

The primary MIME type for .bz2 files is application/x-bzip2.

Is it safe to open .bz2 files?

bzip2compressed archive (.bz2) files are generally safe to open. They are classified as low risk because they primarily contain data rather than executable code. However, always ensure files come from a trusted source.