Table of Contents

Skein256 Class

Definition

Namespace
Bodu.Security.Cryptography
Assembly
Bodu.Security.Cryptography.dll
Package
Bodu.Security.Cryptography 1.2.0
Source
Skein.256.cs

Computes a hash using the Skein-256 variant of the Skein hash function, built on top of the Threefish256Cipher tweakable block cipher. This class cannot be inherited.

public sealed class Skein256 : Skein, ICryptoTransform, IDisposable
Inheritance
Skein256
Implements
Inherited Members
Extension Methods

Examples

using var skein = new Skein256(); // Skein-256-256
byte[] digest = skein.ComputeHash(message);

using var skeinMac = new Skein256 { Key = key }; // Skein-MAC-256-256
byte[] tag = skeinMac.ComputeHash(message);

Remarks

Skein256 operates on a 256-bit internal state in 32-byte blocks. The permitted output sizes are 128, 160, 224, and 256 bits; 256 bits is the default and matches the Skein 1.3 specification's canonical truncation set for this state size.

Supplying a non-empty Key turns the instance into the keyed Skein-MAC-256 variant by prepending a KEY UBI phase to the standard CFG → MSG → OUT pipeline. The key length is not fixed: any byte sequence from zero up to MaxKeySize / 8 bytes is valid.

Parameters at a glance.

  • State / block size: 256 bits (32 bytes).
  • Output sizes: 128, 160, 224, or 256 bits - default 256.
  • Underlying cipher: Threefish256Cipher tweakable block cipher under UBI mode.
  • Optional variable-length key: 0-MaxKeySize / 8 bytes.

When to choose Skein-256. The narrowest Skein variant - pick it when 32-byte output is enough and the surrounding system has standardized on Skein. Skein512 is the more common default and offers a stronger security margin; Skein1024 is for cases that want the widest state. For new general-purpose hashing without an interop constraint Blake2b or SHA-2 is the more widely deployed default.

Constructors

Skein256()

Initializes a new instance of the Skein256 class that produces a 256-bit digest.

public Skein256()

Skein256(int)

Initializes a new instance of the Skein256 class with the specified output size.

public Skein256(int hashSize)

Parameters

hashSize int

The requested output size, in bits. Must be one of 128, 160, 224, or 256.

Exceptions

ArgumentOutOfRangeException

hashSize is not one of the permitted output sizes for Skein-256.

Applies to

ProductVersions
.NET8, 10

See Also

Threefish256Cipher
Skein
Skein512
Skein1024
Threefish256