diff --git a/cmd/mothd/httpd_test.go b/cmd/mothd/httpd_test.go
index fc4ae9a..1f95869 100644
--- a/cmd/mothd/httpd_test.go
+++ b/cmd/mothd/httpd_test.go
@@ -69,6 +69,26 @@ func TestHttpd(t *testing.T) {
 	} else if r.Body.String() != `{"status":"success","data":{"short":"already registered","description":"team ID has already been registered"}}` {
 		t.Error("Register failed", r.Body.String())
 	}
+	
+	// Test participant assignment
+
+	if r := hs.TestRequest("/assign", map[string]string{"pid": "badParticipantID"}); r.Result().StatusCode != 200 {
+		t.Error(r.Result())
+	} else if r.Body.String() != `{"status":"fail","data":{"short":"unable to associate participant and team","description":"participant ID not found in list of valid participant IDs"}}` {
+		t.Error("Assignment failed", r.Body.String())
+	}
+
+	if r := hs.TestRequest("/assign", map[string]string{"id": "bad team id", "pid": "participantID"}); r.Result().StatusCode != 200 {
+		t.Error(r.Result())
+	} else if r.Body.String() != `{"status":"fail","data":{"short":"unable to associate participant and team","description":"Provided team does not exist, or is not registered"}}` {
+		t.Error("Assignment failed", r.Body.String())
+	}
+
+	if r := hs.TestRequest("/assign", map[string]string{"id": "teamID", "pid": "participantID"}); r.Result().StatusCode != 200 {
+		t.Error(r.Result())
+	} else if r.Body.String() != `{"status":"success","data":{"short":"assigned","description":"participant and team have been associated"}}` {
+		t.Error("Assignment failed", r.Body.String())
+	}
 
 	time.Sleep(TestMaintenanceInterval)
 
@@ -100,13 +120,19 @@ func TestHttpd(t *testing.T) {
 		t.Error("Unexpected body", r.Body.String())
 	}
 
-	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "moo"}); r.Result().StatusCode != 200 {
+	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "answer123", "pid": "bad participant ID"}); r.Result().StatusCode != 200 {
+		t.Error(r.Result())
+	} else if r.Body.String() != `{"status":"fail","data":{"short":"not accepted","description":"invalid participant ID"}}` {
+		t.Error("Unexpected body", r.Body.String())
+	}
+
+	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "moo", "pid": "participantID"}); r.Result().StatusCode != 200 {
 		t.Error(r.Result())
 	} else if r.Body.String() != `{"status":"fail","data":{"short":"not accepted","description":"incorrect answer"}}` {
 		t.Error("Unexpected body", r.Body.String())
 	}
 
-	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "answer123"}); r.Result().StatusCode != 200 {
+	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "answer123", "pid": "participantID"}); r.Result().StatusCode != 200 {
 		t.Error(r.Result())
 	} else if r.Body.String() != `{"status":"success","data":{"short":"accepted","description":"1 points awarded in pategory"}}` {
 		t.Error("Unexpected body", r.Body.String())
@@ -129,7 +155,7 @@ func TestHttpd(t *testing.T) {
 		t.Error("Didn't unlock next puzzle")
 	}
 
-	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "answer123"}); r.Result().StatusCode != 200 {
+	if r := hs.TestRequest("/answer", map[string]string{"cat": "pategory", "points": "1", "answer": "answer123", "pid": "participantID"}); r.Result().StatusCode != 200 {
 		t.Error(r.Result())
 	} else if r.Body.String() != `{"status":"fail","data":{"short":"not accepted","description":"error awarding points: points already awarded to this team in this category"}}` {
 		t.Error("Unexpected body", r.Body.String())
diff --git a/cmd/mothd/server_test.go b/cmd/mothd/server_test.go
index 6b6e621..1e57835 100644
--- a/cmd/mothd/server_test.go
+++ b/cmd/mothd/server_test.go
@@ -17,6 +17,7 @@ func NewTestServer() *MothServer {
 
 	state := NewTestState()
 	afero.WriteFile(state, "teamids.txt", []byte("teamID\n"), 0644)
+	afero.WriteFile(state, "participantids.txt", []byte("participantID\n"), 0644)
 	afero.WriteFile(state, "messages.html", []byte("messages.html"), 0644)
 	go state.Maintain(TestMaintenanceInterval)
 
@@ -72,6 +73,16 @@ func TestProdServer(t *testing.T) {
 		t.Error("Wrong error for duplicate registration:", err)
 	}
 
+	if err := handler.AssignParticipant(); err != nil {
+		t.Error(err)
+	}
+	if err := handler.AssignParticipant(); err == nil {
+		t.Error("Assigning a participant twice should have raised an error")
+	} else if err != ErrAlreadyRegistered {
+		t.Error("Wrong error for duplicate registration:", err)
+	}
+	
+
 	if r, _, err := handler.ThemeOpen("/index.html"); err != nil {
 		t.Error(err)
 	} else if contents, err := ioutil.ReadAll(r); err != nil {
@@ -128,7 +139,7 @@ func TestProdServer(t *testing.T) {
 	}
 
 	if err := anonHandler.CheckAnswer("pategory", 1, "answer123"); err == nil {
-		t.Error("Invalid team ID was able to get points with correct answer")
+		t.Error("Invalid participant ID was able to get points with correct answer")
 	}
 	if err := handler.CheckAnswer("pategory", 1, "answer123"); err != nil {
 		t.Error("Right answer marked wrong", err)
diff --git a/cmd/mothd/state_test.go b/cmd/mothd/state_test.go
index 21f1ea2..b163968 100644
--- a/cmd/mothd/state_test.go
+++ b/cmd/mothd/state_test.go
@@ -35,6 +35,7 @@ func TestState(t *testing.T) {
 	mustExist("initialized")
 	mustExist("enabled")
 	mustExist("hours.txt")
+	mustExist("participantids.txt")
 
 	teamIDsBuf, err := afero.ReadFile(s.Fs, "teamids.txt")
 	if err != nil {
@@ -69,9 +70,53 @@ func TestState(t *testing.T) {
 		t.Error("Incorrect team name:", name)
 	}
 
+	// Participant ID tests
+
+	participantIDsBuf, err := afero.ReadFile(s.Fs, "participantids.txt")
+	if err != nil {
+		t.Errorf("Reading participantids.txt: %v", err)
+	}
+
+	participantIDs := bytes.Split(participantIDsBuf, []byte("\n"))
+	if (len(participantIDs) != 101) || (len(participantIDs[100]) > 0) {
+		t.Errorf("There weren't 100 participantIDs, there were %d", len(participantIDs))
+	}
+	participantID := string(participantIDs[0])
+
+	if _, err := s.ParticipantTeam(participantID); err == nil {
+		t.Errorf("Bad participant ID lookup didn't return error")
+	}
+
+	if err := s.AssignParticipant("bad participant ID", "bad team ID"); err == nil {
+		t.Errorf("Assigning bad participant ID didn't raise an error")
+	}
+
+	if err := s.AssignParticipant(participantID, "bad team ID"); err == nil {
+		t.Errorf("Assigning participant to bad team ID didn't raise an error")
+	}
+
+	if err := s.AssignParticipant("bad participant ID", teamID); err == nil {
+		t.Errorf("Assigning bad participant ID to valid team ID didn't raise an error")
+	}
+
+	if err:= s.AssignParticipant(participantID, teamID); err != nil {
+		t.Errorf("Error assigning participant to team: %s -> %s", participantID, teamID)
+	}
+	if err:= s.AssignParticipant(participantID, teamID); err == nil {
+		t.Errorf("Assigning participant to team a second time should fail")
+	}
+	s.refresh()
+	if id, err := s.ParticipantTeam(participantID); err != nil {
+		t.Error(err)
+	} else if id != teamID {
+		t.Error("Incorrect team ID:", id)
+	}
+
+
+	// Award tests
 	category := "poot"
 	points := 3928
-	if err := s.AwardPoints(teamID, category, points); err != nil {
+	if err := s.AwardPoints(participantID, category, points); err != nil {
 		t.Error(err)
 	}
 	// Flex duplicate detection with different timestamp
@@ -82,7 +127,7 @@ func TestState(t *testing.T) {
 		f.Close()
 	}
 
-	s.AwardPoints(teamID, category, points)
+	s.AwardPoints(participantID, category, points)
 	s.refresh()
 	pl = s.PointsLog()
 	if len(pl) != 1 {
@@ -94,11 +139,11 @@ func TestState(t *testing.T) {
 		t.Errorf("Incorrect logged award %v", pl)
 	}
 
-	if err := s.AwardPoints(teamID, category, points); err == nil {
+	if err := s.AwardPoints(participantID, category, points); err == nil {
 		t.Error("Duplicate points award after refresh didn't fail")
 	}
 
-	if err := s.AwardPoints(teamID, category, points+1); err != nil {
+	if err := s.AwardPoints(participantID, category, points+1); err != nil {
 		t.Error("Awarding more points:", err)
 	}
 
@@ -112,7 +157,7 @@ func TestState(t *testing.T) {
 	if len(s.PointsLog()) != 0 {
 		t.Errorf("Intentional parse error breaks pointslog")
 	}
-	if err := s.AwardPoints(teamID, category, points); err != nil {
+	if err := s.AwardPoints(participantID, category, points); err != nil {
 		t.Error(err)
 	}
 	s.refresh()