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AES Cryptfile format (.aes)

.aes file signature | application/octet-stream

AES Cryptfile format. (The fourth byte is the version number, 0-2.)

Safe

Magic Bytes

Offset 0
41 43 53 44

Sources: Gary Kessler

All Known Signatures

2 signature variants are documented for .aes files across multiple sources.

Hex Signature Offset Sources
41 43 53 44 0 Gary Kessler
41 45 53 0 Gary Kessler

Extension

.aes

MIME Type

application/octet-stream

Byte Offset

0

Risk Level

Safe

Validation Code

How to validate .aes files in Python

Python 
def is_aes(file_path: str) -> bool:
    """Check if file is a valid AES by magic bytes."""
    signature = bytes([0x41, 0x43, 0x53, 0x44])
    with open(file_path, "rb") as f:
        return f.read(4) == signature

How to validate .aes files in Node.js

Node.js 
function isAES(buffer: Buffer): boolean {
  const signature = Buffer.from([0x41, 0x43, 0x53, 0x44]);
  return buffer.subarray(0, 4).equals(signature);
}

How to validate .aes files in Go

Go 
func IsAES(data []byte) bool {
    signature := []byte{0x41, 0x43, 0x53, 0x44}
    if len(data) < 4 {
        return false
    }
    return bytes.Equal(data[:4], signature)
}

API Endpoint

GET /api/v1/aes
curl https://filesignature.org/api/v1/aes

See the full API documentation for all endpoints and parameters.

Frequently Asked Questions

What is a .aes file?

A .aes file is a AES Cryptfile format file. AES Cryptfile format. (The fourth byte is the version number, 0-2.)

What are the magic bytes for .aes files?

The magic bytes for AES Cryptfile format files are 41 43 53 44 at byte offset 0. These bytes uniquely identify the file format regardless of the file extension.

How do I validate a .aes file?

To validate a .aes file, read the first bytes of the file and compare them against the known magic bytes (41 43 53 44) at offset 0. This is more reliable than checking the file extension alone, as extensions can be renamed.

What is the MIME type for .aes files?

There is no officially registered MIME type for .aes files. Systems typically use application/octet-stream as a generic fallback when handling this format.

Is it safe to open .aes files?

AES Cryptfile format (.aes) 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.