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The method java.lang.Object.equals(), by default, is unable to compare composite objects such as cryptographic keys. Most Key classes do not fail to provide an equals() implementation that overrides Object's default implementation.equals(). In such cases, the components of the composite object must be compared individually to ensure correctness.

Noncompliant Code Example

This noncompliant code example compares two keys using the equals() method but the . The keys may compare unequal even when they represent the same value.

private static boolean keysEqual(Key key1, Key key2) {
  if (key1.equals(key2)) {
    return true;
  }
  return false;
}

Compliant Solution

Wiki MarkupThis compliant solution uses the {{equals()}} method as a first test and then compares the encoded version of the keys to facilitate provider-independent behavior. For example, it can be checked if a {{RSAPrivateKey}} and {{RSAPrivateCrtKey}} represent an equivalent private key. \[[Sun 06|AA. Java References#Sun 06]\]behavior. It checks whether an RSAPrivateKey and an RSAPrivateCrtKey represent equivalent private keys [Oracle 2011b].

private static boolean keysEqual(Key key1, Key key2) {
  if (key1.equals(key2)) {
    return true;
  }

  if (Arrays.equals(key1.getEncoded(), key2.getEncoded())) {
    return true;
  }

  // More code for different types of keys here.
  // For example, the following code can check ifwhether
  // an RSAPrivateKey and an RSAPrivateCrtKey are equal:
  if ((key1 instanceof RSAPrivateKey) &&
      (key2 instanceof RSAPrivateKey)) {
  
    if ((((RSAKey) key1).getModulus().equals(((RSAKey) key2).getModulus()))
       && (((RSAPrivateKey) key1).getPrivateExponent().equals(
           ((RSAPrivateKey) key2).getPrivateExponent()))) {
  
      return true;
    }
  }
  return false;
}

Risk Assessment

Using Object.equals() to compare cryptographic keys may not yield accurate results.

Automated Detection

TODO

Related Vulnerabilities

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

References

\[[API 06|AA. Java References#API 06]\] 
\[[Sun 06|AA. Java References#Sun 06]\] [Determining If Two Keys Are Equal|http://java.sun.com/javase/6/docs/technotes/guides/security/crypto/CryptoSpec.html#Determining%20If%20Two%20Keys%20Are%20Equal] (JCA Reference Guide)

Automated Detection

Bibliography

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Image Added Image Added Image AddedMSC34-J. Do not base critical decisions on IP addresses or DNS lookups      49. Miscellaneous (MSC)      99. The Void (VOID)