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PK4 (.pk4)

.pk4 file signature | application/octet-stream

zip file formatand formats based on it, such asEPUB,JAR,ODF,OOXML

Safe

Magic Bytes

Offset 0
50 4B 03 04 50 4B 05 06 50 4B 07 08

Sources: Wikipedia

Extension

.pk4

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .pk4 files in Python

Python 
def is_pk4(file_path: str) -> bool:
    """Check if file is a valid PK4 by magic bytes."""
    signature = bytes([0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08])
    with open(file_path, "rb") as f:
        return f.read(12) == signature

How to validate .pk4 files in Node.js

Node.js 
function isPK4(buffer: Buffer): boolean {
  const signature = Buffer.from([0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08]);
  return buffer.subarray(0, 12).equals(signature);
}

How to validate .pk4 files in Go

Go 
func IsPK4(data []byte) bool {
    signature := []byte{0x50, 0x4B, 0x03, 0x04, 0x50, 0x4B, 0x05, 0x06, 0x50, 0x4B, 0x07, 0x08}
    if len(data) < 12 {
        return false
    }
    return bytes.Equal(data[:12], signature)
}

API Endpoint

GET /api/v1/pk4
curl https://filesignature.org/api/v1/pk4

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .pk4 file?

A .pk4 file is a PK4 file. zip file formatand formats based on it, such asEPUB,JAR,ODF,OOXML

What are the magic bytes for .pk4 files?

The magic bytes for PK4 files are 50 4B 03 04 50 4B 05 06 50 4B 07 08 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .pk4 file?

To validate a .pk4 file, read the first bytes of the file and compare them against the known magic bytes (50 4B 03 04 50 4B 05 06 50 4B 07 08) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .pk4 files?

There is no officially registered MIME type for .pk4 files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .pk4 files?

PK4 (.pk4) 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.