Hong Kong HKID Number Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching hong kong hkid number, ported and verified for Go. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

// Hong Kong HKID Number
// ReDoS-checked | RegexVault — Identity & PII > National Identity Numbers

package validation

import "regexp"

var hongKongHkidNumberRe = regexp.MustCompile(`^([A-Z]{1,2})([0-9]{6})\(([0-9A])\)$`)

func ValidateHongKongHkidNumber(s string) bool {
    return hongKongHkidNumberRe.MatchString(s)
}

// Example
// fmt.Println(ValidateHongKongHkidNumber("A123456(7)")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > National Identity Numbers category and has been checked for ReDoS risk. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. 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

Structure: 1-2 uppercase letters + 6 digits + check character (0-9 or A) in parentheses. A single letter prefix is padded with a space for checksum calculation. The check character is computed via weighted sum mod 11.