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TripleDES.IsWeakKey Method

Determines whether the specified key is weak.

Namespace:  System.Security.Cryptography
Assembly:  mscorlib (in mscorlib.dll)

'Declaration
Public Shared Function IsWeakKey ( _
	rgbKey As Byte() _
) As Boolean

Parameters

rgbKey
Type: System.Byte()

The secret key to test for weakness.

Return Value

Type: System.Boolean
true if the key is weak; otherwise, false.

ExceptionCondition
CryptographicException

The size of the rgbKey parameter is not valid.

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.

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

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
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