SHA-256 Hash Regex for Go

What this pattern does

This page provides a lightweight, single-purpose regular expression for matching sha-256 hash, 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

// SHA-256 Hash
// ReDoS-safe | RegexVault — Security > Password Formats

package validation

import "regexp"

var sha256HashRe = regexp.MustCompile(`^[a-f0-9]{64}$`)

func ValidateSha256Hash(s string) bool {
    return sha256HashRe.MatchString(s)
}

// Example
// fmt.Println(ValidateSha256Hash("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")) // true

Test Cases

When to use this pattern

This pattern is drawn from the Security > Password Formats 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 is part of the SHA-2 family, still cryptographically secure. Used for certificates, code signing, TLS, and file integrity. For password hashing, always use SHA-256 within a proper password hashing function (PBKDF2, Argon2) — raw SHA-256 alone is not suitable for passwords.