123 (.123)
.123 file signature | application/vnd.lotus-1-2-3;version=97+9.x
123 is a legacy spreadsheet file format created by Lotus Development Corporation for Lotus 1-2-3, later supported by IBM through its office software products. It was used to store worksheets, formulas, charts, and business data for accounting, planning, and data analysis, and could be opened by compatible spreadsheet applications. As an obsolete format, it is generally safe to inspect, though older files may not preserve all features in modern software.
Magic Bytes
Offset 0
00 00 1A 00 03 10 04 00
Sources: Apache Tika
Extension
.123
MIME Type
application/vnd.lotus-1-2-3;version=97+9.x
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .123 files in Python
def is_123(file_path: str) -> bool:
"""Check if file is a valid 123 by magic bytes."""
signature = bytes([0x00, 0x00, 0x1A, 0x00, 0x03, 0x10, 0x04, 0x00])
with open(file_path, "rb") as f:
return f.read(8) == signatureHow to validate .123 files in Node.js
function is123(buffer: Buffer): boolean {
const signature = Buffer.from([0x00, 0x00, 0x1A, 0x00, 0x03, 0x10, 0x04, 0x00]);
return buffer.subarray(0, 8).equals(signature);
}How to validate .123 files in Go
func Is123(data []byte) bool {
signature := []byte{0x00, 0x00, 0x1A, 0x00, 0x03, 0x10, 0x04, 0x00}
if len(data) < 8 {
return false
}
return bytes.Equal(data[:8], signature)
}API Endpoint
/api/v1/123
curl https://filesignature.org/api/v1/123
See the full API documentation for all endpoints and parameters.
Related Formats
Frequently Asked Questions
What is a .123 file?
A .123 file is identified by the magic bytes 00 00 1A 00 03 10 04 00 at byte offset 0. 123 is a legacy spreadsheet file format created by Lotus Development Corporation for Lotus 1-2-3, later supported by IBM through its office software products. It was used to store worksheets, formulas, charts, and business data for accounting, planning, and data analysis, and could be opened by compatible spreadsheet applications. As an obsolete format, it is generally safe to inspect, though older files may not preserve all features in modern software.
What are the magic bytes for .123 files?
The magic bytes for 123 files are 00 00 1A 00 03 10 04 00 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .123 file?
To validate a .123 file, read the first bytes of the file and compare them against the known magic bytes (00 00 1A 00 03 10 04 00) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .123 files?
The primary MIME type for .123 files is application/vnd.lotus-1-2-3;version=97+9.x.
Is it safe to open .123 files?
123 (.123) 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.