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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 fail to provide an equals() implementation that overrides Object.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. 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

This compliant solution uses the equals() method as a first test and then compares the encoded version of the keys to facilitate provider-independent behavior. In this example, we check It checks whether an RSAPrivateKey and an RSAPrivateCrtKey represent equivalent private keys [Sun 2006Oracle 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 whether
  // 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;
}

Automated Detection

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Tool	Version	Checker	Description
The Checker Framework	Include Page The Checker Framework_V The Checker Framework_V	Interning Checker	Errors in equality testing and interning (see Chapter 5)

Bibliography

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Image Modified Image Modified Image ModifiedMSC03-J. Never hardcode sensitive information      49. Miscellaneous (MSC)       MSC05-J. Store passwords using a hash function