EUI-64 (64-bit Extended Unique Identifier) Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching eui-64 (64-bit extended unique identifier), ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# EUI-64 (64-bit Extended Unique Identifier)
# ReDoS-safe | RegexVault — Web & Network > MAC Address

import re

eui64_64bit_extended_unique_identifier_pattern = re.compile(r'^[0-9a-fA-F]{2}(?:[:-][0-9a-fA-F]{2}){7}$')

def validate_eui64_64bit_extended_unique_identifier(value: str) -> bool:
    return bool(eui64_64bit_extended_unique_identifier_pattern.fullmatch(value))

# Example
print(validate_eui64_64bit_extended_unique_identifier("00:1a:2b:ff:fe:3c:4d:5e"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > MAC Address category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

EUI-64 is constructed from a MAC-48 by inserting ff:fe in the middle. The Universal/Local bit (bit 6 of octet 1) is flipped to form IPv6 Modified EUI-64 interface identifiers.