diff --git a/commit/merkleroot/rmn/controller_test.go b/commit/merkleroot/rmn/controller_test.go
index c9fd9c5a..e1f3a25f 100644
--- a/commit/merkleroot/rmn/controller_test.go
+++ b/commit/merkleroot/rmn/controller_test.go
@@ -415,15 +415,11 @@ func TestClient_ComputeReportSignatures(t *testing.T) {
 		const numNodes = 8
 		rmnNodes := make([]rmntypes.HomeNodeInfo, numNodes)
 		for i := 0; i < numNodes; i++ {
-			// deterministically create a public key by seeding with a 32char string.
-			publicKey, _, err := ed25519.GenerateKey(
-				strings.NewReader(strconv.Itoa(i) + strings.Repeat("x", 31)))
-			require.NoError(t, err)
 			rmnNodes[i] = rmntypes.HomeNodeInfo{
 				ID:                    rmntypes.NodeID(i + 1),
 				PeerID:                [32]byte{1, 2, 3},
 				SupportedSourceChains: mapset.NewSet(chainS1, chainS2),
-				OffchainPublicKey:     &publicKey,
+				OffchainPublicKey:     getDeterministicPubKey(t),
 			}
 		}
 
@@ -648,7 +644,7 @@ func Test_controller_validateSignedObservationResponse(t *testing.T) {
 				{
 					ID:                    20,
 					SupportedSourceChains: mapset.NewSet[cciptypes.ChainSelector](cciptypes.ChainSelector(2)),
-					OffchainPublicKey:     &ed25519.PublicKey{},
+					OffchainPublicKey:     getDeterministicPubKey(t),
 				},
 			},
 		},
@@ -743,6 +739,14 @@ func Test_newRequestID(t *testing.T) {
 	}
 }
 
+func getDeterministicPubKey(t *testing.T) *ed25519.PublicKey {
+	// deterministically create a public key by seeding with a 32char string.
+	publicKey, _, err := ed25519.GenerateKey(
+		strings.NewReader(strconv.Itoa(1) + strings.Repeat("x", 31)))
+	require.NoError(t, err)
+	return &publicKey
+}
+
 func (ts *testSetup) waitForObservationRequestsToBeSent(
 	rmnClient *mockPeerClient,
 	homeF int,
diff --git a/commit/merkleroot/rmn/crypto.go b/commit/merkleroot/rmn/crypto.go
index 00d7be2c..e43321d6 100644
--- a/commit/merkleroot/rmn/crypto.go
+++ b/commit/merkleroot/rmn/crypto.go
@@ -47,6 +47,12 @@ func verifyObservationSignature(
 	msg := append([]byte(signedObservationPrefix), observationBytesSha256[:]...)
 	msgSha256 := sha256.Sum256(msg)
 
+	if rmnNode.OffchainPublicKey == nil {
+		return fmt.Errorf("node %d has no offchain public key", rmnNode.ID)
+	}
+	if len(*rmnNode.OffchainPublicKey) != ed25519.PublicKeySize {
+		return fmt.Errorf("node %d has an invalid offchain public key", rmnNode.ID)
+	}
 	isValid := verifier.Verify(*rmnNode.OffchainPublicKey, msgSha256[:], signedObs.Signature)
 	if !isValid {
 		return fmt.Errorf("observation signature does not match node %d public key", rmnNode.ID)