XZ archive file
application/x-xz
Magic Bytes
Offset: 0
FD 37 7A 58 5A 00
The XZ archive file is a lossless data compression format developed by the Tukaani Project and maintained within the XZ Utils software suite. It is primarily used for distributing software packages, source code, and Linux kernel images due to the high compression ratios provided by the LZMA2 algorithm. While the format is inherently safe, an upstream supply chain compromise was identified in the build tools in 2024, highlighting the need for rigorous software verification.
Validation Code
How to validate .xz files in Python
Python
def is_xz(file_path: str) -> bool:
"""Check if file is a valid XZ by magic bytes."""
signature = bytes([0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00])
with open(file_path, "rb") as f:
return f.read(6) == signatureHow to validate .xz files in Node.js
Node.js
function isXZ(buffer: Buffer): boolean {
const signature = Buffer.from([0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00]);
return buffer.subarray(0, 6).equals(signature);
}
Go
func IsXZ(data []byte) bool {
signature := []byte{0xFD, 0x37, 0x7A, 0x58, 0x5A, 0x00}
if len(data) < 6 {
return false
}
return bytes.Equal(data[:6], signature)
}API Endpoint
GET
/api/v1/xz
curl https://filesignature.org/api/v1/xz