Certificate Fingerprint (SHA-256) Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching certificate fingerprint (sha-256), ported and verified for Go. In security-sensitive code, using an unverified regex can open the door to both false positives and denial-of-service attacks. 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

// Certificate Fingerprint (SHA-256)
// ReDoS-safe | RegexVault — Security > Certificates & PKI

package validation

import "regexp"

var certificateFingerprintSha256Re = regexp.MustCompile(`^[0-9A-F]{2}(?::[0-9A-F]{2}){31}$`)

func ValidateCertificateFingerprintSha256(s string) bool {
    return certificateFingerprintSha256Re.MatchString(s)
}

// Example
// fmt.Println(ValidateCertificateFingerprintSha256("2B:8F:1B:57:33:0D:BB:A2:D0:7A:6C:DD:EC:1A:57:D0:5D:FB:F9:29:35:46:8E:11:33:46:93:D0:F2:CC:54:CA")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Security > Certificates & PKI category and carries a ReDoS-safe certification. 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

SHA-256 fingerprint = 256 bits = 32 bytes = 64 hex chars = 32 colon-separated pairs. Used to verify a certificate's identity (pin it) in TLS certificate pinning, SSH known_hosts, and manual certificate verification.