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OpenOffice spreadsheet magic bytes (.sxc)

.sxc file signature: 50 4B 03 04 | application/vnd.sun.xml.calc

OpenOffice Spreadsheet (SXC) is a spreadsheet file format created by Sun Microsystems and later maintained by the Apache OpenOffice project. It is used to store worksheets, formulas, charts, and related data in OpenOffice Calc and compatible office suites. The format is largely legacy, having been supplanted by OpenDocument formats, and files from untrusted sources should still be opened with standard caution.

Safe

Magic Bytes

Offset 0
50 4B 03 04

Sources: Gary Kessler

Extension

.sxc

MIME Type

application/vnd.sun.xml.calc

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .sxc files in Python

Python 
def is_sxc(file_path: str) -> bool:
    """Check if file is a valid SXC by magic bytes."""
    signature = bytes([0x50, 0x4B, 0x03, 0x04])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .sxc files in Node.js

Node.js 
function isSXC(buffer: Buffer): boolean {
  const signature = Buffer.from([0x50, 0x4B, 0x03, 0x04]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .sxc files in Go

Go 
func IsSXC(data []byte) bool {
    signature := []byte{0x50, 0x4B, 0x03, 0x04}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

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

See the full API documentation for all endpoints and parameters.

Related Formats

.sxd .sxi .sxw

Frequently Asked Questions

What is a .sxc file?

A .sxc file is an OpenOffice spreadsheet. OpenOffice Spreadsheet (SXC) is a spreadsheet file format created by Sun Microsystems and later maintained by the Apache OpenOffice project. It is used to store worksheets, formulas, charts, and related data in OpenOffice Calc and compatible office suites. The format is largely legacy, having been supplanted by OpenDocument formats, and files from untrusted sources should still be opened with standard caution.

What are the magic bytes for .sxc files?

The magic bytes for OpenOffice spreadsheet (.sxc) files are 50 4B 03 04 at byte offset 0. These bytes identify the file format more reliably than the extension alone.

How do I validate a .sxc file?

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

What is the MIME type for .sxc files?

The primary MIME type for .sxc files is application/vnd.sun.xml.calc.

Is it safe to open .sxc files?

OpenOffice spreadsheet (.sxc) 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.