Semi-weak keys are pairs of keys that result in ciphers that are easy to break. If text is encrypted with a semi-weak key, encrypting the resulting cipher with the partner of that semi-weak key returns the original text. There are six known semi-weak key pairs for the Data Encryption Standard (System.Security.Cryptography.DES) algorithm; this method checks for those semi-weak keys.

Attempting to set a semi-weak key results in a System.Security.Cryptography.CryptographicException. When DESCryptoServiceProvider.GenerateKey is called to create a random key, a semi-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