# Cwe 321 Hardcoded Crypto Key

> Use this skill when you need to remediate CWE-321 (Hard-coded Cryptographic Key) vulnerabilities in Java code. Triggers on SAST findings, security reviews, or when fixing hard-coded cryptographic key issues.

- Skill: `developerscoffee/cwe-321-hardcoded-crypto-key` (Agent Skill)
- Install (CLI): `npx skillmds@latest add developerscoffee/cwe-321-hardcoded-crypto-key`
- Raw SKILL.md: https://api.skillmd.com/api/skills/developerscoffee/cwe-321-hardcoded-crypto-key/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- License: MIT
- Author: DevelopersCoffee (https://skillmd.com/u/developerscoffee)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/developerscoffee/cwe-321-hardcoded-crypto-key

---


# CWE-321 Hard-coded Cryptographic Key

## Description

Hard-coded Cryptographic Key

Reference:
https://cwe.mitre.org/data/definitions/321.html


**OWASP Category**: A02:2021 – Cryptographic Failures


---

## Vulnerable Pattern


### ❌ Example 1: Vulnerable Pattern

```java
// VULNERABLE: Hardcoded encryption key
private static final String SECRET_KEY = "MySecretKey12345";
private static final byte[] IV = "InitVector123456".getBytes();

SecretKeySpec keySpec = new SecretKeySpec(SECRET_KEY.getBytes(), "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(IV));
```


**Why it's vulnerable:** This pattern is vulnerable to Hard-coded Cryptographic Key




---

## Deterministic Fix


### ✅ Secure Implementation: Secure Implementation

```java
// SECURE: Generate keys securely and store externally
// Key generation (do once, store securely)
KeyGenerator keyGen = KeyGenerator.getInstance("AES");
keyGen.init(256, new SecureRandom());
SecretKey secretKey = keyGen.generateKey();

// Generate random IV for each encryption
byte[] iv = new byte[16];
new SecureRandom().nextBytes(iv);

// Load key from secure storage
@Value("${encryption.key}")
private String base64Key;

public SecretKey getKey() {
    byte[] keyBytes = Base64.getDecoder().decode(base64Key);
    return new SecretKeySpec(keyBytes, "AES");
}

// Use with random IV
Cipher cipher = Cipher.getInstance("AES/GCM/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, getKey(), new GCMParameterSpec(128, iv));
```


**Why it's secure:** Implements proper protection against Hard-coded Cryptographic Key




---

## Detection Pattern

Look for these patterns in your codebase:


```bash
# Find hardcoded key patterns
grep -rn "SecretKeySpec.*getBytes\|new.*Key.*\"" --include="*.java"
```



---

## Remediation Steps


1. Remove hardcoded keys from source code

2. Generate keys using KeyGenerator with SecureRandom

3. Store keys in secure key management system

4. Use random IV/nonce for each encryption operation


---

## Key Imports

```java

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import java.security.SecureRandom;

```

---

## Verification

After remediation:


- Run SAST scanner to confirm vulnerability is resolved

- Review all instances of the vulnerable pattern

- Add unit tests that verify the secure implementation

- Check for similar patterns in related code


---

## Trigger Examples

```
Fix CWE-321 vulnerability
Resolve Hard-coded Cryptographic Key issue
Secure this Java code against hard-coded cryptographic key
SAST reports CWE-321
```

---

## Common Vulnerable Locations

| Layer | Files | Patterns |
|-------|-------|----------|

| Controller | `*Controller.java` | User input handling |

| Service | `*Service.java` | Business logic |

| Repository | `*Repository.java` | Data access |


---

## References


- [CWE-321: Hard-coded Crypto Key](https://cwe.mitre.org/data/definitions/321.html)


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**Source**: Generated by [Java CWE Security Skills Generator](https://github.com/DevelopersCoffee/java-cwe-security-skills)
**Last Updated**: 2026-03-07