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JBIG2 (.jbig2)

.jbig2 file signature | image/x-jbig2

JBIG2 is a bi-level image compression format standardized by the Joint Bi-level Image Experts Group and maintained through ISO/IEC and related standards bodies. It is used to encode scanned documents, fax images, and monochrome page content in document workflows and archival systems. Although generally safe, JBIG2 support has appeared in some security exploits in document processors, so files from untrusted sources should be handled with updated software.

Safe

Magic Bytes

Offset 0
97 4A 42 32 0D 0A 1A 0A

Sources: Apache Tika

Extension

.jbig2

MIME Type

image/x-jbig2

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .jbig2 files in Python

Python 
def is_jbig2(file_path: str) -> bool:
    """Check if file is a valid JBIG2 by magic bytes."""
    signature = bytes([0x97, 0x4A, 0x42, 0x32, 0x0D, 0x0A, 0x1A, 0x0A])
    with open(file_path, "rb") as f:
        return f.read(8) == signature

How to validate .jbig2 files in Node.js

Node.js 
function isJBIG2(buffer: Buffer): boolean {
  const signature = Buffer.from([0x97, 0x4A, 0x42, 0x32, 0x0D, 0x0A, 0x1A, 0x0A]);
  return buffer.subarray(0, 8).equals(signature);
}

How to validate .jbig2 files in Go

Go 
func IsJBIG2(data []byte) bool {
    signature := []byte{0x97, 0x4A, 0x42, 0x32, 0x0D, 0x0A, 0x1A, 0x0A}
    if len(data) < 8 {
        return false
    }
    return bytes.Equal(data[:8], signature)
}

API Endpoint

GET /api/v1/jbig2
curl https://filesignature.org/api/v1/jbig2

See the full API documentation for all endpoints and parameters.

Related Formats

.jb2

Frequently Asked Questions

What is a .jbig2 file?

A .jbig2 file is identified by the magic bytes 97 4A 42 32 0D 0A 1A 0A at byte offset 0. JBIG2 is a bi-level image compression format standardized by the Joint Bi-level Image Experts Group and maintained through ISO/IEC and related standards bodies. It is used to encode scanned documents, fax images, and monochrome page content in document workflows and archival systems. Although generally safe, JBIG2 support has appeared in some security exploits in document processors, so files from untrusted sources should be handled with updated software.

What are the magic bytes for .jbig2 files?

The magic bytes for JBIG2 files are 97 4A 42 32 0D 0A 1A 0A at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .jbig2 file?

To validate a .jbig2 file, read the first bytes of the file and compare them against the known magic bytes (97 4A 42 32 0D 0A 1A 0A) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .jbig2 files?

The primary MIME type for .jbig2 files is image/x-jbig2.

Is it safe to open .jbig2 files?

JBIG2 (.jbig2) 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.