Class Poly1305Mac

Namespace

CryptoHives.Foundation.Security.Cryptography.Mac

Assembly

CryptoHives.Foundation.Security.Cryptography.dll

Computes the Poly1305 message authentication code as defined in RFC 8439.

public sealed class Poly1305Mac : IMac, IDisposable

Inheritance

object

Poly1305Mac

Implements

IMac

IDisposable

Inherited Members

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

object.GetType()

Examples

byte[] key = new byte[32]; // 32-byte one-time key
byte[] data = Encoding.UTF8.GetBytes("Hello, World!");

using var mac = Poly1305Mac.Create(key);
mac.Update(data);
byte[] tag = new byte[16];
mac.Finalize(tag);

Remarks

Poly1305 is a high-speed, one-time authenticator designed by Daniel J. Bernstein. It takes a 32-byte one-time key and a message to produce a 16-byte tag.

Important: The key must be unique for every message. Reusing a key across multiple messages completely compromises authenticity. In practice, the key is typically derived from a session key and nonce (e.g., by ChaCha20-Poly1305).

This class provides a streaming IMac interface for incremental hashing. For stack-only, zero-allocation usage, see CryptoHives.Foundation.Security.Cryptography.Cipher.Poly1305Core.

Constructors

Poly1305Mac(byte[])

Initializes a new instance of the Poly1305Mac class.

public Poly1305Mac(byte[] key)

Parameters

key byte[]

The 32-byte one-time key.

Exceptions

ArgumentException

The key is not 32 bytes.

Poly1305Mac(ReadOnlySpan<byte>)

Initializes a new instance of the Poly1305Mac class.

public Poly1305Mac(ReadOnlySpan<byte> key)

Parameters

key ReadOnlySpan<byte>

The 32-byte one-time key.

Exceptions

ArgumentException

The key is not 32 bytes.

Fields

KeySizeBytes

The required key size in bytes.

public const int KeySizeBytes = 32

Field Value

int

TagSizeBytes

The MAC output size in bytes.

public const int TagSizeBytes = 16

Field Value

int

Properties

AlgorithmName

Gets the name of the MAC algorithm.

public string AlgorithmName { get; }

Property Value

string

MacSize

Gets the MAC output size in bytes.

public int MacSize { get; }

Property Value

int

Methods

ComputeHash(byte[])

Computes the Poly1305 tag for the given data in a single operation.

public byte[] ComputeHash(byte[] data)

Parameters

data byte[]

The data to authenticate.

Returns

byte[]

The 16-byte MAC tag.

ComputeHash(ReadOnlySpan<byte>)

Computes the Poly1305 tag for the given data in a single operation.

public byte[] ComputeHash(ReadOnlySpan<byte> data)

Parameters

data ReadOnlySpan<byte>

The data to authenticate.

Returns

byte[]

The 16-byte MAC tag.

Create(byte[])

Creates a new instance of the Poly1305Mac class.

public static Poly1305Mac Create(byte[] key)

Parameters

key byte[]

The 32-byte one-time key.

Returns

Poly1305Mac

A new Poly1305 MAC instance.

Create(ReadOnlySpan<byte>)

Creates a new instance of the Poly1305Mac class.

public static Poly1305Mac Create(ReadOnlySpan<byte> key)

Parameters

key ReadOnlySpan<byte>

The 32-byte one-time key.

Returns

Poly1305Mac

A new Poly1305 MAC instance.

Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

public void Dispose()

Finalize(Span<byte>)

Computes the final MAC tag and writes it to destination.

public void Finalize(Span<byte> destination)

Parameters

destination Span<byte>

The buffer to receive the MAC tag. Must be at least MacSize bytes.

Exceptions

ArgumentException

destination is too small.

ObjectDisposedException

Thrown when the instance has been disposed.

Hash(byte[], byte[])

Computes the Poly1305 tag for the specified key and data in a single operation.

public static byte[] Hash(byte[] key, byte[] data)

Parameters

key byte[]

The 32-byte one-time key.

data byte[]

The data to authenticate.

Returns

byte[]

The 16-byte MAC tag.

Reset()

Resets the MAC to its initial state so it can be reused with the same key.

public void Reset()

Update(ReadOnlySpan<byte>)

Feeds input data into the MAC computation.

public void Update(ReadOnlySpan<byte> input)

Parameters

input ReadOnlySpan<byte>

The data to process.

Exceptions

ObjectDisposedException

Thrown when the instance has been disposed.