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TripleDES.IsWeakKey Method

Determines whether the specified key is weak.

[Visual Basic]
Public Shared Function IsWeakKey( _
   ByVal rgbKey() As Byte _
) As Boolean
[C#]
public static bool IsWeakKey(
 byte[] rgbKey
);
[C++]
public: static bool IsWeakKey(
 unsigned char rgbKey __gc[]
);
[JScript]
public static function IsWeakKey(
   rgbKey : Byte[]
) : Boolean;

Parameters

rgbKey
The secret key to be tested for weakness.

Return Value

true if the key is weak; otherwise, false.

Exceptions

Exception Type Condition
CryptographicException The size of the rgbKey parameter is not valid.

Remarks

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. In 128-bit mode if the first 64 bits are the same as the last 64 bits, the key is weak. In 192-bit mode if the first 64 bits are the same as the second 64 bits, or if the second 64 bits are the same as the last 64 bits, the key is weak.

An attempt to set a weak key will result in a CryptographicException. When GenerateKey is called to create a random key, a weak key will never be returned.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

TripleDES Class | TripleDES Members | System.Security.Cryptography Namespace | Cryptographic Services

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