Get mandatory api

security/src/main/java/module-info.java

@@ -1,7 +1,7 @@
 module tessera.security {
   // requires java.base;
   requires java.xml.bind;
-  //  requires cryptacular;
+  requires cryptacular;
   requires org.slf4j;
   requires tessera.config;
   requires tessera.shared;

tessera-core/src/main/java/com/quorum/tessera/transaction/TransactionManager.java

@@ -6,6 +6,7 @@
 import com.quorum.tessera.encryption.PublicKey;
 import java.util.List;
 import java.util.ServiceLoader;
+import java.util.Set;
 
 public interface TransactionManager {
 
@@ -27,6 +28,8 @@ public interface TransactionManager {
 
   List<PublicKey> getParticipants(MessageHash transactionHash);
 
+  Set<PublicKey> getMandatoryRecipients(MessageHash transactionHash);
+
   /**
    * @see Enclave#defaultPublicKey()
    * @return

tessera-core/src/main/java/com/quorum/tessera/transaction/internal/TransactionManagerImpl.java

@@ -513,6 +513,12 @@ public List<PublicKey> getParticipants(final MessageHash transactionHash) {
     return payload.getRecipientKeys();
   }
 
+  @Override
+  public Set<PublicKey> getMandatoryRecipients(MessageHash transactionHash) {
+    final EncodedPayload payload = this.fetchPayload(transactionHash);
+    return payload.getMandatoryRecipients();
+  }
+
   @Override
   public PublicKey defaultPublicKey() {
     return enclave.defaultPublicKey();

tessera-core/src/test/java/com/quorum/tessera/transaction/internal/TransactionManagerTest.java

@@ -1717,6 +1717,35 @@ public void getParticipantsReturnsAllRecipients() {
     verify(encryptedTransactionDAO).retrieveByHash(any(MessageHash.class));
   }
 
+  @Test
+  public void getMandatoryRecipients() {
+
+    MessageHash transactionHash = mock(MessageHash.class);
+    when(transactionHash.getHashBytes()).thenReturn("DUMMY_TRANSACTION".getBytes());
+
+    final PublicKey senderKey = mock(PublicKey.class);
+    final PublicKey recipientKey = mock(PublicKey.class);
+
+    final byte[] input = "SOMEDATA".getBytes();
+    final EncryptedTransaction encryptedTransaction = mock(EncryptedTransaction.class);
+    final EncodedPayload encodedPayload = mock(EncodedPayload.class);
+    when(encodedPayload.getRecipientKeys()).thenReturn(List.of(senderKey, recipientKey));
+    when(encodedPayload.getMandatoryRecipients()).thenReturn(Set.of(recipientKey));
+    when(encryptedTransaction.getEncodedPayload()).thenReturn(input);
+
+    when(encryptedTransactionDAO.retrieveByHash(transactionHash))
+        .thenReturn(Optional.of(encryptedTransaction));
+
+    when(payloadEncoder.decode(input)).thenReturn(encodedPayload);
+
+    final Set<PublicKey> participants = transactionManager.getMandatoryRecipients(transactionHash);
+
+    assertThat(participants).containsExactly(recipientKey);
+
+    verify(payloadEncoder).decode(input);
+    verify(encryptedTransactionDAO).retrieveByHash(any(MessageHash.class));
+  }
+
   @Test
   public void defaultPublicKey() {
     transactionManager.defaultPublicKey();

tessera-jaxrs/transaction-jaxrs/src/main/java/com/quorum/tessera/q2t/TransactionResource4.java

@@ -1,6 +1,7 @@
 package com.quorum.tessera.q2t;
 
 import static com.quorum.tessera.version.MandatoryRecipientsVersion.MIME_TYPE_JSON_4;
+import static javax.ws.rs.core.MediaType.TEXT_PLAIN;
 
 import com.quorum.tessera.api.SendRequest;
 import com.quorum.tessera.api.SendResponse;
@@ -12,6 +13,12 @@
 import com.quorum.tessera.encryption.PublicKey;
 import com.quorum.tessera.privacygroup.PrivacyGroupManager;
 import com.quorum.tessera.transaction.TransactionManager;
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.ExampleObject;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import java.net.URI;
 import java.net.URLEncoder;
@@ -232,4 +239,42 @@ public Response sendSignedTransaction(
 
     return Response.created(location).entity(responseEntity).build();
   }
+
+  @Operation(
+      summary = "/transaction/{hash}/mandatory",
+      operationId = "getMandatoryRecipients",
+      description = "get list of mandatory recipient public keys for a transaction")
+  @ApiResponse(
+      responseCode = "200",
+      description = "comma-separated list of mandatory recipients",
+      content =
+          @Content(
+              schema =
+                  @Schema(
+                      type = "string",
+                      description = "comma-separated list of mandatory recipients"),
+              examples =
+                  @ExampleObject(
+                      "ROAZBWtSacxXQrOe3FGAqJDyJjFePR5ce4TSIzmJ0Bc=,BULeR8JyUWhiuuCMU/HLA0Q5pzkYT+cHII3ZKBey3Bo=")))
+  @GET
+  @Path("/transaction/{hash}/mandatory")
+  @Produces(TEXT_PLAIN)
+  public Response getMandatoryRecipients(
+      @Parameter(
+              description = "hash indicating encrypted payload to get mandatory recipients for",
+              schema = @Schema(format = "base64"))
+          @PathParam("hash")
+          final String ptmHash) {
+    LOGGER.debug("Received mandatory recipients list API request for key {}", ptmHash);
+
+    MessageHash transactionHash =
+        Optional.of(ptmHash).map(Base64.getDecoder()::decode).map(MessageHash::new).get();
+
+    final String mandatoryRecipients =
+        transactionManager.getMandatoryRecipients(transactionHash).stream()
+            .map(PublicKey::encodeToBase64)
+            .collect(Collectors.joining(","));
+
+    return Response.ok(mandatoryRecipients).build();
+  }
 }

tessera-jaxrs/transaction-jaxrs/src/test/java/com/quorum/tessera/q2t/TransactionResource4Test.java

@@ -12,6 +12,7 @@
 import com.quorum.tessera.privacygroup.PrivacyGroupManager;
 import com.quorum.tessera.transaction.TransactionManager;
 import java.util.Base64;
+import java.util.Set;
 import javax.ws.rs.core.Response;
 import org.junit.After;
 import org.junit.Before;
@@ -160,4 +161,23 @@ public void sendSignedTransactionWithMandatoryRecipients() {
         .containsExactlyInAnyOrder(base64AffectedHash1, base64AffectedHash2);
     assertThat(obj.getMandatoryRecipients()).hasSize(1);
   }
+
+  @Test
+  public void getMandatoryRecipients() {
+    byte[] data = "DUMMY_HASH".getBytes();
+
+    final String dummyPtmHash = Base64.getEncoder().encodeToString(data);
+
+    PublicKey recipient = mock(PublicKey.class);
+    when(recipient.encodeToBase64()).thenReturn("BASE64ENCODEDKEY");
+
+    when(transactionManager.getMandatoryRecipients(any(MessageHash.class)))
+        .thenReturn(Set.of(recipient));
+
+    Response response = transactionResource.getMandatoryRecipients(dummyPtmHash);
+
+    assertThat(response.getStatus()).isEqualTo(200);
+    assertThat(response.getEntity()).isEqualTo("BASE64ENCODEDKEY");
+    verify(transactionManager).getMandatoryRecipients(any(MessageHash.class));
+  }
 }

tests/acceptance-test/src/test/java/com/quorum/tessera/test/rest/SendMandatoryRecipientsIT.java

@@ -138,6 +138,25 @@ public void sendTransactionWithMandatoryRecipients() throws UnsupportedEncodingE
     EncodedPayload payloadC = PayloadEncoder.create().decode(payloadOnC);
     assertThat(payloadC.getMandatoryRecipients())
         .containsExactly(PublicKey.from(Base64.getDecoder().decode(c.getPublicKey())));
+
+    // Validate recipients data in Node C using /mandatory call
+
+    final String encodedHash = URLEncoder.encode(hash, UTF_8.toString());
+
+    final Response getMandatoryResponse =
+        c.getRestClient()
+            .target(c.getQ2TUri())
+            .path("/transaction")
+            .path(encodedHash)
+            .path("/mandatory")
+            .request()
+            .buildGet()
+            .invoke();
+
+    assertThat(getMandatoryResponse).isNotNull();
+    assertThat(getMandatoryResponse.getStatus()).isEqualTo(200);
+    String mandatoryList = getMandatoryResponse.readEntity(String.class);
+    assertThat(mandatoryList).isEqualTo(c.getPublicKey());
   }
 
   @Test