Base64-Encoded Potential Secret Regex for Go

What this pattern does

This page provides a well-structured, multi-part regular expression for matching base64-encoded potential secret, 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

// Base64-Encoded Potential Secret
// ReDoS-safe | RegexVault — Security > Secrets & Config

package validation

import "regexp"

var base64encodedPotentialSecretRe = regexp.MustCompile(`^(?:[A-Za-z0-9+/]{4}){10,}(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$`)

func ValidateBase64encodedPotentialSecret(s string) bool {
    return base64encodedPotentialSecretRe.MatchString(s)
}

// Example
// fmt.Println(ValidateBase64encodedPotentialSecret("dGhpcyBpcyBhIHRlc3Qgc3RyaW5nIGZvciBlbmNvZGluZw==")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Security > Secrets & Config 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

Pattern matches 40+ base64 characters (10+ groups of 4). High-entropy base64 strings of this length commonly represent secrets, keys, or encoded credentials. Always pair with entropy analysis — legitimate base64 text will have lower entropy than random bytes.