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DFONT (.dfont)

.dfont file signature | application/octet-stream

DFONT is a font container format developed by Apple for macOS, used to store TrueType and related font data in a resource-based structure. It has been used for system fonts, desktop publishing, and legacy Mac application compatibility. DFONT is largely a legacy format, but it remains generally safe to open; however, like other font files, malformed examples can exploit parser vulnerabilities in vulnerable software.

Safe

Magic Bytes

Offset 0
00 01 00 00 00

Sources: Wikipedia

Extension

.dfont

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .dfont files in Python

Python 
def is_dfont(file_path: str) -> bool:
    """Check if file is a valid DFONT by magic bytes."""
    signature = bytes([0x00, 0x01, 0x00, 0x00, 0x00])
    with open(file_path, "rb") as f:
        return f.read(5) == signature

How to validate .dfont files in Node.js

Node.js 
function isDFONT(buffer: Buffer): boolean {
  const signature = Buffer.from([0x00, 0x01, 0x00, 0x00, 0x00]);
  return buffer.subarray(0, 5).equals(signature);
}

How to validate .dfont files in Go

Go 
func IsDFONT(data []byte) bool {
    signature := []byte{0x00, 0x01, 0x00, 0x00, 0x00}
    if len(data) < 5 {
        return false
    }
    return bytes.Equal(data[:5], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Related Formats

.ttc .ttf .afm .eot .fon .otf

Frequently Asked Questions

What is a .dfont file?

A .dfont file is identified by the magic bytes 00 01 00 00 00 at byte offset 0. DFONT is a font container format developed by Apple for macOS, used to store TrueType and related font data in a resource-based structure. It has been used for system fonts, desktop publishing, and legacy Mac application compatibility. DFONT is largely a legacy format, but it remains generally safe to open; however, like other font files, malformed examples can exploit parser vulnerabilities in vulnerable software.

What are the magic bytes for .dfont files?

The magic bytes for DFONT files are 00 01 00 00 00 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .dfont file?

To validate a .dfont file, read the first bytes of the file and compare them against the known magic bytes (00 01 00 00 00) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .dfont files?

There is no officially registered MIME type for .dfont files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .dfont files?

DFONT (.dfont) 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.