# Use of a Broken or Risky Cryptographic Algorithm (CWE-327)

The product uses a broken or risky cryptographic algorithm or protocol.

**Stack:** Python

- Prevalence: 高 頻繁に悪用される
- Impact: ハイ 3 件の重大度ハイのルール
- Prevention: 文書化済み 4 件の修正例

**OWASP:** Cryptographic Failures (A02:2021-Cryptographic Failures) - #2

## Description

Cryptographic algorithms are the backbone of modern information security. Using algorithms that have known weaknesses, such as MD5 or DES, can make it trivial for attackers to defeat the protection.

## Prevention

1 件の Shoulder 検出ルールに基づく Broken Cryptographic Algorithm の予防策。

### Python

Replace MD5/SHA-1/DES/RC4 with SHA-256/SHA-3 for hashing and AES-GCM for encryption

## Warning Signs

- [MEDIUM] use of weak or deprecated cryptographic algorithms like MD5, SHA-1,
DES, or RC4

## Consequences

- アプリケーションデータの読み取り
- 保護メカニズムの回避

## Mitigations

- 対称暗号には AES-256 を使用する
- 非対称暗号には RSA-2048 以上または ECDSA を使用する
- ハッシュには SHA-256 または SHA-3 を使用する

## Detection

- Total rules: 4
- Languages: go, javascript, typescript, python

## Rules by Language

### Python (1 rules)

- **Weak Cryptographic Algorithm** [MEDIUM]: Detects use of weak or deprecated cryptographic algorithms like MD5, SHA-1,
DES, or RC4. Use modern algorithms like SHA-256, SHA-3, AES, or ChaCha20.
  - Remediation: Use SHA-256/SHA-3 for hashing and AES for encryption.

```python
import hashlib
from Crypto.Cipher import AES
from Crypto.Random import get_random_bytes

# Secure hashing
hash_value = hashlib.sha256(data).hexdigest()

# Secure encryption
key = get_random_bytes(32)  # AES-256
cipher = AES.new(key, AES.MODE_GCM)
ciphertext, tag = cipher.encrypt_and_digest(data)
```

Learn more: https://shoulder.dev/learn/python/cwe-327/weak-crypto-algorithm