IncrementalSignatureVerification Struct

Represents the state of a signature verification algorithm that can be incrementally updated with segments of data.

public readonly struct IncrementalSignatureVerification

The type provides an “init, update, final” interface for verifying data given a public key and a signature. First, a state needs to be initialized with the public key. The state can then be updated zero or more times with segments of data. Finalizing the state gives a result as to whether verification of the concatenated segments was successful.


IncrementalSignatureVerification instances have value-type semantics: Passing an instance to a method or assigning it to a variable creates a copy of the state. It is therefore recommended to always pass instances using ref, in, or out.


The following C# example shows how to verify multiple segments of data given a public key and a signature:

// define some data to be verified
var lines = new[]
    "Luke Skywalker has returned to\n",
    "his home planet of Tatooine in\n",
    "an attempt to rescue his\n",
    "friend Han Solo from the\n",
    "clutches of the vile gangster\n",
    "Jabba the Hutt.\n",

// select the Ed25519ph algorithm
var algorithm = SignatureAlgorithm.Ed25519ph;

// obtain the public key
var publicKey = ...

// obtain the signature
var signature = ...

// initialize the state with the public key
IncrementalSignatureVerification.Initialize(publicKey, out var state);

// incrementally update the state with the data
foreach (var line in lines)
    IncrementalSignatureVerification.Update(ref state, Encoding.UTF8.GetBytes(line));

// verify the data using the signature
if (IncrementalSignatureVerification.FinalizeAndVerify(ref state, signature))
    // verified!




Gets the algorithm that was used to initialize the state.

public SignatureAlgorithm2? Algorithm { get; }

Property Value

An instance of the SignatureAlgorithm2 class, or null if the current instance has not been initialized yet or if it has been finalized.

Static Methods

Initialize(PublicKey, out IncrementalSignatureVerification)

Initializes the IncrementalSignatureVerification state with the specified public key.

public static void Initialize(
    PublicKey publicKey,
    out IncrementalSignatureVerification state)


The public key to use for verifying the data.
When this method returns, contains the initialized state.


publicKey is null.
publicKey.Algorithm is not an instance of the SignatureAlgorithm2 class.

Update(ref IncrementalSignatureVerification, ReadOnlySpan<byte>)

Updates the IncrementalSignatureVerification state with the specified span of bytes.

public static void Update(
    ref IncrementalSignatureVerification state,
    ReadOnlySpan<byte> data)


The state to be updated with data.
A segment of the data to verify.


state has not been initialized yet or has already been finalized.

FinalizeAndVerify(ref IncrementalSignatureVerification, ReadOnlySpan<byte>)

Completes the verification.

public static bool FinalizeAndVerify(
    ref IncrementalSignatureVerification state,
    ReadOnlySpan<byte> signature)


The state to be finalized.
The signature of the data to verify.

Return Value

true if verification succeeds; otherwise, false.


state has not been initialized yet or has already been finalized.

Thread Safety

Any public static members of this type are thread safe. Any instance members are not guaranteed to be thread safe. As with any other type, reading and writing to a shared variable that contains an instance of this type must be protected by a lock to guarantee thread safety.

See Also