MSC01-J. Do not use insecure or weak cryptographic algorithms

Applications in general should avoid, and security-related applications must avoid, use of insecure or weak cryptographic primitives. The computational capacity of modern computers permits circumvent such cryptography via brute-force attacks. For example, the DES encryption algorithm is considered highly insecure; messages encrypted using DES have been decrypted by brute force within a single day by machines such as the Electronic Frontier Foundation's (EFF) Deep Crack.

Noncompliant Code Example

This noncompliant code example encrypts a String input by using a weak cryptographic algorithm (DES).

SecretKey key = KeyGenerator.getInstance("DES").generateKey();
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, key); 

// Encode bytes as UTF8; strToBeEncrypted contains the input string
// that is to be encrypted 
byte[] encoded = strToBeEncrypted.getBytes("UTF8");
    
// Perform encryption
byte[] encrypted = cipher.doFinal(encoded);

Compliant Solution

This compliant solution uses the more secure AES algorithm to perform the encryption. Decryption follows similar logic and has been omitted from this discussion.

Cipher cipher = Cipher.getInstance("AES");             
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(128); // 192 and 256 bits may be unavailable

SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();

SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

// Encode bytes as UTF8; strToBeEncrypted contains the input string
// that is to be encrypted 
byte[] encoded = strToBeEncrypted.getBytes("UTF8");
    
// Perform encryption
byte[] encrypted = cipher.doFinal(encoded);   

Risk Assessment

Use of mathematically and computationally insecure cryptographic algorithms can result in the disclosure of sensitive information.

Related Vulnerabilities

Search for vulnerabilities resulting from the violation of this guideline on the CERT website.

Bibliography

[[API 2006]]
[[MITRE 2009]] CWE ID 327 "Use of a Broken or Risky Cryptographic Algorithm"

49. Miscellaneous (MSC)      49. Miscellaneous (MSC)