FH4 (.fh4)
.fh4 file signature | image/x-freehand
Magic Bytes
Offset 0
41 47 44 32
Sources: Apache Tika
All Known Signatures
6 signature variants are documented for .fh4 files across multiple sources.
| Hex Signature | Offset | Sources |
|---|---|---|
| 41 47 44 32 | 0 | Apache Tika |
| 41 47 44 33 | 0 | Apache Tika |
| 41 47 44 34 | 0 | Apache Tika |
| 46 72 65 65 48 61 6E 64 31 30 | 0 | Apache Tika |
| 46 72 65 65 48 61 6E 64 31 31 | 0 | Apache Tika |
| 46 72 65 65 48 61 6E 64 31 32 | 0 | Apache Tika |
Extension
.fh4
MIME Type
image/x-freehand
Byte Offset
0
Risk Level
Safe
Validation Code
How to validate .fh4 files in Python
def is_fh4(file_path: str) -> bool:
"""Check if file is a valid FH4 by magic bytes."""
signature = bytes([0x41, 0x47, 0x44, 0x32])
with open(file_path, "rb") as f:
return f.read(4) == signatureHow to validate .fh4 files in Node.js
function isFH4(buffer: Buffer): boolean {
const signature = Buffer.from([0x41, 0x47, 0x44, 0x32]);
return buffer.subarray(0, 4).equals(signature);
}How to validate .fh4 files in Go
func IsFH4(data []byte) bool {
signature := []byte{0x41, 0x47, 0x44, 0x32}
if len(data) < 4 {
return false
}
return bytes.Equal(data[:4], signature)
}API Endpoint
/api/v1/fh4
curl https://filesignature.org/api/v1/fh4
See the full API documentation for all endpoints and parameters.
Frequently Asked Questions
What is a .fh4 file?
A .fh4 file is a FH4 file.
What are the magic bytes for .fh4 files?
The magic bytes for FH4 files are 41 47 44 32 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.
How do I validate a .fh4 file?
To validate a .fh4 file, read the first bytes of the file and compare them against the known magic bytes (41 47 44 32) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.
What is the MIME type for .fh4 files?
The primary MIME type for .fh4 files is image/x-freehand.
Is it safe to open .fh4 files?
FH4 (.fh4) 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.