Salsa20 Class
Definition
- Namespace
- Bodu.Security.Cryptography
- Assembly
- Bodu.Security.Cryptography.dll
- Package
- Bodu.Security.Cryptography 1.2.0
- Source
- Salsa20.cs
Provides a managed implementation of the Salsa20 stream cipher specified by Daniel J. Bernstein. This class cannot be inherited.
public sealed class Salsa20 : SymmetricStreamAlgorithm, IDisposable- Inheritance
-
Salsa20
- Implements
- Inherited Members
- Extension Methods
Examples
using Bodu.Security.Cryptography;
using Bodu.Security.Cryptography.Extensions;
using var salsa = new Salsa20();
salsa.GenerateKey(); // 256-bit
salsa.GenerateNonce(); // 64-bit nonce
byte[] ciphertext = salsa.Encrypt(plaintext);
byte[] roundTrip = salsa.Decrypt(ciphertext);Remarks
Salsa20 is an additive stream cipher and an eSTREAM software-portfolio finalist. It uses a 128- or 256-bit key, a 64-bit nonce, and a 64-bit block counter to generate a keystream that is XORed with the plaintext. This class exposes the raw, confidentiality-only cipher with no authentication; for new designs prefer an AEAD construction, or the closely related ChaCha20 which has largely superseded Salsa20.
Like the other stream ciphers in this library it is self-inverse: CreateEncryptor() and CreateDecryptor() are interchangeable. The nonce is supplied through the Nonce property.
Parameters at a glance.
- Key size: 128 or 256 bits (16 or 32 bytes); 256-bit is the default.
- Nonce (IV) size: 64 bits (8 bytes).
- Block counter: 64-bit, starting at InitialCounter (default 0).
Nonce reuse is catastrophic. A given (key, nonce) pair must encrypt at most one message. The
64-bit nonce is too short to generate randomly without collision risk; for random nonces prefer the extended-nonce
XSalsa20 variant.
Constructors
Salsa20()
Initializes a new instance of the Salsa20 class with default parameters.
public Salsa20()Remarks
The default configuration uses a 256-bit key and a 64-bit nonce, with the block counter starting at 0. Assign KeySize to 128 before generating or supplying a key to use a 128-bit key.
Properties
InitialCounter
Gets or sets the initial 64-bit block counter used when generating the keystream.
public ulong InitialCounter { get; set; }Property Value
- ulong
The starting block-counter value. The default is 0.
Remarks
eSTREAM test vectors start the counter at 0. Set this before creating an encryptor or decryptor when matching an external counter convention.
Methods
Create()
Creates a new Salsa20 instance with default parameters.
public static Salsa20 Create()Returns
CreateStreamCipher(byte[], byte[])
Builds a configured IStreamCipher engine from the validated key and nonce.
protected override IStreamCipher CreateStreamCipher(byte[] key, byte[] nonce)Parameters
keybyte[]The key, already validated to the algorithm's key size.
noncebyte[]The nonce, already validated to the algorithm's nonce size.
Returns
- IStreamCipher
A new IStreamCipher engine positioned at the start of its keystream.
Remarks
Implementations receive a key and nonce whose lengths have already been checked by the base class, so they need only construct their engine. Ownership of the returned engine transfers to the caller.
Applies to
| Product | Versions |
|---|---|
| .NET | 8, 10 |