Compressed ISO (.cso)
.cso file signature | application/octet-stream
Compressed ISO (CISO) CD image
Magic Bytes
Offset 0
43 49 53 4F
Sources: Gary Kessler
Extension
.cso
MIME Type
application/octet-stream
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .cso files in Python
def is_cso(file_path: str) -> bool:
"""Check if file is a valid CSO by magic bytes."""
signature = bytes([0x43, 0x49, 0x53, 0x4F])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .cso files in Node.js
function isCSO(buffer: Buffer): boolean {
const signature = Buffer.from([0x43, 0x49, 0x53, 0x4F]);
return buffer.subarray(0, 4).equals(signature);
}How to validate .cso files in Go
func IsCSO(data []byte) bool {
signature := []byte{0x43, 0x49, 0x53, 0x4F}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
/api/v1/cso
curl https://filesignature.org/api/v1/cso
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .cso file?
A .cso file is a Compressed ISO file. Compressed ISO (CISO) CD image
What are the magic bytes for .cso files?
The magic bytes for Compressed ISO files are 43 49 53 4F at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .cso file?
To validate a .cso file, read the first bytes of the file and compare them against the known magic bytes (43 49 53 4F) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .cso files?
There is no officially registered MIME type for .cso files. Systems typically use application/octet-stream as a generic fallback when handling this format.
Is it safe to open .cso files?
Compressed ISO (.cso) 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.