{"success":true,"data":{"ext":"efx","name":"eFax file format","description":"The eFax file format (EFX) is a document format associated with the eFax fax service, originally developed and maintained by eFax, a digital fax provider operated by J2 Global. It is used for sending, receiving, and archiving fax documents in workflows that replace or supplement traditional telephone faxing, including business correspondence and records management. The format is generally considered safe, although like other document files it should be opened only from trusted sources.","mime":[],"risk_level":"Safe","signatures":[{"hex":"DC FE","offset":0,"sources":[{"name":"Gary Kessler","url":"https://www.garykessler.net/library/file_sigs_GCK_latest.html"}]}],"related":[],"usage":{"python":"def is_efx(file_path: str) -> bool:\n    \"\"\"Check if file is a valid EFX by magic bytes.\"\"\"\n    signature = bytes([0xDC, 0xFE])\n    with open(file_path, \"rb\") as f:\n        return f.read(2) == signature","node":"function isEFX(buffer: Buffer): boolean {\n  const signature = Buffer.from([0xDC, 0xFE]);\n  return buffer.subarray(0, 2).equals(signature);\n}","go":"func IsEFX(data []byte) bool {\n    signature := []byte{0xDC, 0xFE}\n    if len(data) < 2 {\n        return false\n    }\n    return bytes.Equal(data[:2], signature)\n}"}}}