XLD
application/vnd.ms-excel
Magic Bytes
Offset: 2080
4D 69 63 72 6F 73 6F 66 74 20 45 78 63 65 6C 20 35 2E 30 20 57 6F 72 6B 73 68 65 65 74
The XLD file format is a legacy spreadsheet container originally developed by Microsoft as part of the Excel 5.0 software suite. It was primarily utilized for storing early electronic worksheets, formulas, and data tables before the transition to more modern binary and XML-based spreadsheet standards. Although largely obsolete in modern workflows, these files are categorized as safe for archival purposes, though they lack the advanced encryption features found in contemporary Excel formats.
Validation Code
How to validate .xld files in Python
Python
def is_xld(file_path: str) -> bool:
"""
Check if file is a valid XLD by magic bytes.
Signature offset: 2080 bytes
"""
signature = bytes([0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, 0x74, 0x20, 0x45, 0x78, 0x63, 0x65, 0x6C, 0x20, 0x35, 0x2E, 0x30, 0x20, 0x57, 0x6F, 0x72, 0x6B, 0x73, 0x68, 0x65, 0x65, 0x74])
with open(file_path, "rb") as f:
f.seek(2080)
return f.read(29) == signatureHow to validate .xld files in Node.js
Node.js
function isXLD(buffer: Buffer): boolean {
// Signature offset: 2080 bytes
const signature = Buffer.from([0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, 0x74, 0x20, 0x45, 0x78, 0x63, 0x65, 0x6C, 0x20, 0x35, 0x2E, 0x30, 0x20, 0x57, 0x6F, 0x72, 0x6B, 0x73, 0x68, 0x65, 0x65, 0x74]);
if (buffer.length < 2109) return false;
return buffer.subarray(2080, 2109).equals(signature);
}
Go
func IsXLD(data []byte) bool {
// Signature offset: 2080 bytes
signature := []byte{0x4D, 0x69, 0x63, 0x72, 0x6F, 0x73, 0x6F, 0x66, 0x74, 0x20, 0x45, 0x78, 0x63, 0x65, 0x6C, 0x20, 0x35, 0x2E, 0x30, 0x20, 0x57, 0x6F, 0x72, 0x6B, 0x73, 0x68, 0x65, 0x65, 0x74}
if len(data) < 2109 {
return false
}
return bytes.Equal(data[2080:2109], signature)
}API Endpoint
GET
/api/v1/xld
curl https://filesignature.org/api/v1/xld