feat: okta bcrypt issue test

okta-bcrypt-issue/go.mod

@@ -0,0 +1,5 @@
+module git.hatter.ink/okta-bcrypt-issue
+
+go 1.24.1
+
+require golang.org/x/crypto v0.40.0 // indirect

okta-bcrypt-issue/go.sum

@@ -0,0 +1,2 @@
+golang.org/x/crypto v0.40.0 h1:r4x+VvoG5Fm+eJcxMaY8CQM7Lb0l1lsmjGBQ6s8BfKM=
+golang.org/x/crypto v0.40.0/go.mod h1:Qr1vMER5WyS2dfPHAlsOj01wgLbsyWtFn/aY+5+ZdxY=

okta-bcrypt-issue/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+// https://n0rdy.foo/posts/20250121/okta-bcrypt-lessons-for-better-apis/
+func main() {
+	// 18 + 55 + 1 = 74, so above 72 characters' limit of BCrypt
+	userId := randomString(18)
+	username := randomString(55)
+	password := "super-duper-secure-password"
+
+	combinedString := fmt.Sprintf("%s:%s:%s", userId, username, password)
+
+	combinedHash, err := bcrypt.GenerateFromPassword([]byte(combinedString), bcrypt.DefaultCost)
+	if err != nil {
+		panic(err)
+	}
+
+	// let's try to break it
+	wrongPassword := "wrong-password"
+	wrongCombinedString := fmt.Sprintf("%s:%s:%s", userId, username, wrongPassword)
+
+	err = bcrypt.CompareHashAndPassword(combinedHash, []byte(wrongCombinedString))
+	if err != nil {
+		fmt.Println("Password is incorrect")
+	} else {
+		fmt.Println("Password is correct")
+	}
+}
+
+func randomString(length int) string {
+	bytes := make([]byte, length)
+	_, err := rand.Read(bytes)
+	if err != nil {
+		panic(err)
+	}
+	return base64.URLEncoding.EncodeToString(bytes)[:length]
+}