OTC
application/vnd.oasis.opendocument.chart-template
Magic Bytes
Offset: 0
50 4B
The OTC file format is an OpenDocument Chart Template maintained by the Organization for the Advancement of Structured Information Standards (OASIS). It is primarily utilized within productivity suites like Apache OpenOffice and LibreOffice to store pre-configured chart layouts and styling data for reusable data visualization. As a ZIP-compressed XML structure, the format is considered safe for general use, though users should ensure that external references within the document are from verified origins.
Validation Code
How to validate .otc files in Python
Python
def is_otc(file_path: str) -> bool:
"""Check if file is a valid OTC by magic bytes."""
signature = bytes([0x50, 0x4B])
with open(file_path, "rb") as f:
return f.read(2) == signatureHow to validate .otc files in Node.js
Node.js
function isOTC(buffer: Buffer): boolean {
const signature = Buffer.from([0x50, 0x4B]);
return buffer.subarray(0, 2).equals(signature);
}
Go
func IsOTC(data []byte) bool {
signature := []byte{0x50, 0x4B}
if len(data) < 2 {
return false
}
return bytes.Equal(data[:2], signature)
}API Endpoint
GET
/api/v1/otc
curl https://filesignature.org/api/v1/otc