Weak keys are keys that result in ciphers that are easy to break. If text is encrypted with a weak key, encrypting the resulting cipher again with the same weak key returns the original text. There are four known weak keys for the Data Encryption Standard (System.Security.Cryptography.DES) algorithm; this method checks for those weak keys.

Attempting to set a weak key results in a System.Security.Cryptography.CryptographicException. When DESCryptoServiceProvider.GenerateKey is called to create a random key, a weak key will never be returned.

Namespace: System.Security.Cryptography
Assembly: mscorlib (in mscorlib.dll)
Assembly Versions: 1.0.5000.0, 2.0.0.0, 4.0.0.0