What is the meaning of 'defaultAlgorithm'? about jwt HOT 1 OPEN

/// <summary>
/// Primary interface that encapsulates an application identity and its trusted parties.
/// This identity is theoretically independent of a process or an application domain but
/// in practice, an identity is tied to an <see cref="AppDomain"/>.
/// </summary>
public interface IApplicationIdentity
{
    /// <summary>
    /// Gets this domain application's identity.
    /// </summary>
    ILocalIdentity Local { get; }

    /// <summary>
    /// Gets the available trusted parties.
    /// </summary>
    IReadOnlyDictionary<JsonEncodedText, IRemoteParty> TrustedParties { get; }

    /// <summary>
    /// Writes a signed Json Web token binary representation of claims for a target <paramref name="audience"/> (that can be
    /// this <see cref="Local"/> itself).
    /// </summary>
    /// <param name="claims">The payload.</param>
    /// <param name="audience">The target audience.</param>
    /// <param name="output">The binary output.</param>
    /// <param name="options">Options that defaults to <see cref="JwtWriteOptions.Default"/>.</param>
    void Sign( IEnumerable<KeyValuePair<string, object>> claims, ITrustedParty audience, IBufferWriter<byte> output, JwtWriteOptions? options = null );

    /// <summary>
    /// Writes an encrypted and signed token binary representation of claims for a target <paramref name="audience"/> (that can be
    /// this <see cref="Local"/> itself).
    /// </summary>
    /// <param name="claims">The payload.</param>
    /// <param name="audience">The target audience.</param>
    /// <param name="output">The binary output.</param>
    /// <param name="options">Options that defaults to <see cref="JwtWriteOptions.Default"/>.</param>
    void Encrypt( IEnumerable<KeyValuePair<string, object>> claims, ITrustedParty audience, IBufferWriter<byte> output, JwtWriteOptions? options = null );

    /// <summary>
    /// Attempts to validate a Json Web Token.
    /// </summary>
    /// <param name="monitor">The monitor to use.</param>
    /// <param name="utf8Token">The token.</param>
    /// <returns>The <see cref="ValidatedJwt"/> for which <see cref="ValidatedJwt.Success"/> can be false.</returns>
    ValidatedJwt Validate( IActivityMonitor monitor, ReadOnlySpan<byte> utf8Token );
}

/// <summary>
/// Minimalist definition of a token validation result.
/// </summary>
/// <remarks>
/// There is no status or other error description: validation failures often require a lot of details
/// and should be extensible (to handle specific rules and validators): we simply use the <see cref="CK.Core.ActivityMonitor"/>
/// to log any validation details (warnings or errors).
/// </remarks>
public readonly struct ValidatedJwt
{
    readonly ReadOnlyMemory<byte>? _payload;

    internal ValidatedJwt( ReadOnlyMemory<byte>? payload, bool enc )
    {
        _payload = payload;
        IsEncrypted = enc;
    }

    /// <summary>
    /// Gets whether the token validation succeeded.
    /// </summary>
    public bool Success => _payload is not null;

    /// <summary>
    /// Gets whether the token has been validated and was encrypted.
    /// </summary>
    public bool IsEncrypted { get; }

    /// <summary>
    /// Gets the raw Utf8 encoded payload.
    /// This is null when <see cref="Success"/> is false.
    /// </summary>
    /// <returns>The payload text or null if <see cref="Success"/> is false.</returns>
    public ReadOnlyMemory<byte>? Payload => _payload;
}