diff --git a/tests/conformance/presentation/authorization-request.presentation.spec.ts b/tests/conformance/presentation/authorization-request.presentation.spec.ts
index 07dcda7..4f046f6 100644
--- a/tests/conformance/presentation/authorization-request.presentation.spec.ts
+++ b/tests/conformance/presentation/authorization-request.presentation.spec.ts
@@ -423,6 +423,100 @@ describe(`[${testConfig.name}] Presentation Authorization Request Validation`, (
     }
   });
 
+  // -----------------------------------------------------------------------
+  // RPR-53 — SD-JWT integrity verification failure
+  // -----------------------------------------------------------------------
+
+  test("RPR_053: SD-JWT integrity verification failure | RP rejects a response containing a tampered KB-JWT signature", async () => {
+    const log = baseLog.withTag("RPR_053");
+    const DESCRIPTION =
+      "RP correctly rejected response with tampered SD-JWT KB-JWT signature";
+    log.start("Conformance test: SD-JWT integrity verification failure");
+
+    let testSuccess = false;
+    try {
+      const authResult = await runAuthorizationStep(
+        testConfig.authorizeStepClass,
+      );
+      expect(authResult.success).toBe(true);
+      if (!authResult.response) {
+        throw new Error("auth request was not successful");
+      }
+
+      const { requestObject, responseUri } = authResult.response;
+      const rawVpToken = authResult.response.authorizationResponse
+        .authorizationResponsePayload.vp_token as Record<
+        string,
+        string | string[]
+      >;
+
+      log.info("→ Tampering KB-JWT signature inside the SD-JWT VP vp_token...");
+
+      const tamperedVpToken: Record<string, string | string[]> = {};
+      for (const [credId, sdJwtVp] of Object.entries(rawVpToken)) {
+        const tamperSdJwt = (sdJwt: string): string => {
+          const parts = sdJwt.split("~");
+          const kbJwt = parts[parts.length - 1] ?? "";
+          const jwtParts = kbJwt.split(".");
+          if (jwtParts.length !== 3) return sdJwt;
+          const sig = jwtParts[2] ?? "";
+          const tamperedSig =
+            sig.slice(0, -4) + (sig.endsWith("AAAA") ? "BBBB" : "AAAA");
+          jwtParts[2] = tamperedSig;
+          parts[parts.length - 1] = jwtParts.join(".");
+          return parts.join("~");
+        };
+
+        tamperedVpToken[credId] = Array.isArray(sdJwtVp)
+          ? sdJwtVp.map(tamperSdJwt)
+          : tamperSdJwt(sdJwtVp);
+      }
+
+      log.info(
+        "→ Re-building JARM with tampered vp_token and posting to response_uri...",
+      );
+
+      const metadata = {
+        ...verifierMetadata,
+        authorization_encrypted_response_alg:
+          verifierMetadata.authorization_encrypted_response_alg || "ECDH-ES",
+        authorization_encrypted_response_enc:
+          verifierMetadata.authorization_encrypted_response_enc ||
+          "A128CBC-HS256",
+      };
+
+      const tamperedAuthorizationResponse = await createAuthorizationResponse({
+        authorization_encrypted_response_alg:
+          metadata.authorization_encrypted_response_alg,
+        authorization_encrypted_response_enc:
+          metadata.authorization_encrypted_response_enc,
+        callbacks: {
+          ...partialCallbacks,
+          encryptJwe: getEncryptJweCallback(),
+        },
+        config: ioWalletSdkConfig,
+        requestObject,
+        rpJwks: { jwks: metadata.jwks },
+        vp_token: tamperedVpToken,
+      } as CreateAuthorizationResponseVersionedOptions);
+
+      const formBody = new URLSearchParams({
+        response: tamperedAuthorizationResponse.jarm.responseJwe,
+      });
+      const response = await postToResponseUri(responseUri, {
+        body: formBody.toString(),
+      });
+
+      log.debug(`  Response status: ${response.status}`);
+      log.info("→ Validating RP rejected the tampered SD-JWT...");
+      expect(response.ok).toBe(false);
+
+      testSuccess = true;
+    } finally {
+      log.testCompleted(DESCRIPTION, testSuccess);
+    }
+  });
+
   // -----------------------------------------------------------------------
   // RPR-60 — Invalid HTTP methods
   // -----------------------------------------------------------------------
diff --git a/tests/conformance/presentation/happy.presentation.spec.ts b/tests/conformance/presentation/happy.presentation.spec.ts
index 0524f53..e97848e 100644
--- a/tests/conformance/presentation/happy.presentation.spec.ts
+++ b/tests/conformance/presentation/happy.presentation.spec.ts
@@ -1,5 +1,6 @@
 /* eslint-disable max-lines-per-function */
 import { definePresentationTest } from "#/config/test-metadata";
+import { postToResponseUri } from "#/helpers";
 import { assertPresentationFlowSuccess } from "#/helpers/flow-assertion-helpers";
 import { useTestSummary } from "#/helpers/use-test-summary";
 import { extractClientIdPrefix } from "@pagopa/io-wallet-oid4vp";
@@ -225,6 +226,36 @@ describe(`[${testConfig.name}] Credential Presentation Tests`, () => {
     }
   });
 
+  test("RPR028: response_code has sufficient entropy with at least 32 URL-safe characters.", () => {
+    const log = baseLog.withTag("RPR028");
+
+    log.start("Conformance test: Verifying response_code entropy requirements");
+
+    const DESCRIPTION =
+      "Relying Party correctly provides response_code with sufficient entropy (≥32 characters, URL-safe charset)";
+    let testSuccess = false;
+    try {
+      expect(redirectUriResult.success).toBe(true);
+      expect(redirectUriResult.response?.responseCode).toBeDefined();
+
+      const responseCode = redirectUriResult.response?.responseCode ?? "";
+      log.debug(`  response_code: ${responseCode}`);
+      log.debug(`  Length: ${responseCode.length} characters`);
+
+      expect(responseCode.length).toBeGreaterThanOrEqual(32);
+      log.debug(
+        "  ✅ response_code length meets minimum entropy requirement (≥32)",
+      );
+
+      expect(responseCode).toMatch(/^[a-zA-Z0-9_-]+$/);
+      log.debug("  ✅ response_code uses URL-safe characters only");
+
+      testSuccess = true;
+    } finally {
+      log.testCompleted(DESCRIPTION, testSuccess);
+    }
+  });
+
   test("RPR078: Wallet Attestation request correctly uses standard DCQL query.", () => {
     const log = baseLog.withTag("RPR078");
 
@@ -622,4 +653,50 @@ describe(`[${testConfig.name}] Credential Presentation Tests`, () => {
       log.testCompleted(DESCRIPTION, testSuccess);
     }
   });
+
+  test("RPR_110: HTTP 200 on valid response_uri submission | RP returns HTTP 200 for a well-formed authorization response", async () => {
+    const log = baseLog.withTag("RPR_110");
+    const DESCRIPTION =
+      "RP correctly returns HTTP 200 for a valid authorization response";
+    log.start(
+      "Conformance test: HTTP 200 on valid response_uri submission (success path)",
+    );
+
+    let testSuccess = false;
+    try {
+      log.info(
+        "→ Running a fresh authorization step to obtain a valid JARM and response_uri...",
+      );
+      const ctx = await orchestrator.runThroughAuthorize();
+
+      const authResponse = ctx.authorizationRequestResponse.response;
+      if (!authResponse) {
+        throw new Error(
+          "Fresh authorization step failed: response is undefined",
+        );
+      }
+
+      const freshResponseUri = authResponse.responseUri;
+      const freshJarm = authResponse.authorizationResponse.jarm.responseJwe;
+
+      log.info("→ Posting valid JARM to response_uri...");
+      log.debug(`  response_uri: ${freshResponseUri}`);
+      const formBody = new URLSearchParams({ response: freshJarm });
+      const response = await postToResponseUri(freshResponseUri, {
+        body: formBody.toString(),
+      });
+
+      log.debug(`  Response status: ${response.status}`);
+      log.info("→ Validating RP returned HTTP 200...");
+      expect(
+        response.status,
+        "RP must return HTTP 200 for a valid authorization response per OID4VP spec",
+      ).toBe(200);
+      log.debug("  ✅ response_uri returned HTTP 200");
+
+      testSuccess = true;
+    } finally {
+      log.testCompleted(DESCRIPTION, testSuccess);
+    }
+  });
 });