[PM-22736] Send password hasher (#6112)

* feat: 
  - Add SendPasswordHasher class and interface
  - DI for SendPasswordHasher to use Marker class allowing us to use custom options for the SendPasswordHasher without impacting other PasswordHashers.
* test: Unit tests for SendPasswordHasher implementation
* doc: docs for interface and comments

Co-authored-by: Maciej Zieniuk <167752252+mzieniukbw@users.noreply.github.com>

test/Core.Test/KeyManagement/SendPasswordHasherTests.cs

@@ -0,0 +1,103 @@
+using Bit.Core.KeyManagement.Sends;
+using Bit.Test.Common.AutoFixture;
+using Bit.Test.Common.AutoFixture.Attributes;
+using Microsoft.AspNetCore.Identity;
+using NSubstitute;
+using Xunit;
+
+namespace Bit.Core.Test.KeyManagement.Sends;
+
+[SutProviderCustomize]
+public class SendPasswordHasherTests
+{
+    [Theory]
+    [BitAutoData(PasswordVerificationResult.Success)]
+    [BitAutoData(PasswordVerificationResult.SuccessRehashNeeded)]
+    void VerifyPasswordHash_WithValidMatching_ReturnsTrue(
+        PasswordVerificationResult passwordVerificationResult,
+        SutProvider<SendPasswordHasher> sutProvider,
+        string sendPasswordHash,
+        string inputPasswordHash)
+    {
+        // Arrange
+        sutProvider.GetDependency<IPasswordHasher<SendPasswordHasherMarker>>()
+            .VerifyHashedPassword(Arg.Any<SendPasswordHasherMarker>(), sendPasswordHash, inputPasswordHash)
+            .Returns(passwordVerificationResult);
+
+        // Act
+        var result = sutProvider.Sut.PasswordHashMatches(sendPasswordHash, inputPasswordHash);
+
+        // Assert
+        Assert.True(result);
+        sutProvider.GetDependency<IPasswordHasher<SendPasswordHasherMarker>>()
+            .Received(1)
+            .VerifyHashedPassword(Arg.Any<SendPasswordHasherMarker>(), sendPasswordHash, inputPasswordHash);
+    }
+
+    [Theory, BitAutoData]
+    void VerifyPasswordHash_WithNonMatchingPasswords_ReturnsFalse(
+        SutProvider<SendPasswordHasher> sutProvider,
+        string sendPasswordHash,
+        string inputPasswordHash)
+    {
+        // Arrange
+        sutProvider.GetDependency<IPasswordHasher<SendPasswordHasherMarker>>()
+            .VerifyHashedPassword(Arg.Any<SendPasswordHasherMarker>(), sendPasswordHash, inputPasswordHash)
+            .Returns(PasswordVerificationResult.Failed);
+
+        // Act
+        var result = sutProvider.Sut.PasswordHashMatches(sendPasswordHash, inputPasswordHash);
+
+        // Assert
+        Assert.False(result);
+        sutProvider.GetDependency<IPasswordHasher<SendPasswordHasherMarker>>()
+            .Received(1)
+            .VerifyHashedPassword(Arg.Any<SendPasswordHasherMarker>(), sendPasswordHash, inputPasswordHash);
+    }
+
+    [Theory]
+    [InlineData(null, "inputPassword")]
+    [InlineData("", "inputPassword")]
+    [InlineData("   ", "inputPassword")]
+    [InlineData("sendPassword", null)]
+    [InlineData("sendPassword", "")]
+    [InlineData("sendPassword", "   ")]
+    [InlineData(null, null)]
+    [InlineData("", "")]
+    public void VerifyPasswordHash_WithNullOrEmptyParameters_ReturnsFalse(
+        string? sendPasswordHash,
+        string? inputPasswordHash)
+    {
+        // Arrange
+        var passwordHasher = Substitute.For<IPasswordHasher<SendPasswordHasherMarker>>();
+        var sut = new SendPasswordHasher(passwordHasher);
+
+        // Act
+        var result = sut.PasswordHashMatches(sendPasswordHash, inputPasswordHash);
+
+        // Assert
+        Assert.False(result);
+        passwordHasher.DidNotReceive().VerifyHashedPassword(Arg.Any<SendPasswordHasherMarker>(), Arg.Any<string>(), Arg.Any<string>());
+    }
+
+    [Theory, BitAutoData]
+    void HashPasswordHash_WithValidInput_ReturnsHashedPassword(
+        SutProvider<SendPasswordHasher> sutProvider,
+        string clientHashedPassword,
+        string expectedHashedResult)
+    {
+        // Arrange
+        sutProvider.GetDependency<IPasswordHasher<SendPasswordHasherMarker>>()
+            .HashPassword(Arg.Any<SendPasswordHasherMarker>(), clientHashedPassword)
+            .Returns(expectedHashedResult);
+
+        // Act
+        var result = sutProvider.Sut.HashOfClientPasswordHash(clientHashedPassword);
+
+        // Assert
+        Assert.Equal(expectedHashedResult, result);
+        sutProvider.GetDependency<IPasswordHasher<SendPasswordHasherMarker>>()
+            .Received(1)
+            .HashPassword(Arg.Any<SendPasswordHasherMarker>(), clientHashedPassword);
+    }
+}