diff --git a/client/client.go b/client/client.go
index 2263024..fca676c 100644
--- a/client/client.go
+++ b/client/client.go
@@ -1,17 +1,22 @@
 package client
 
-import "git.andreafazzi.eu/andrea/testhub/models"
+import "git.andreafazzi.eu/andrea/probo/models"
 
 type Response struct {
 	Status  string      `json:"status"`
 	Content interface{} `json:"content"`
 }
 
-type QuizReadAllResponse struct {
+type ReadAllQuizResponse struct {
 	Status  string         `json:"status"`
 	Content []*models.Quiz `json:"content"`
 }
 
+type CreateQuizResponse struct {
+	Status  string       `json:"status"`
+	Content *models.Quiz `json:"content"`
+}
+
 type CreateQuestionRequest struct {
 	Text string `json:"text"`
 }
diff --git a/go.mod b/go.mod
index 50eb730..f3c54e4 100644
--- a/go.mod
+++ b/go.mod
@@ -1,13 +1,13 @@
-module git.andreafazzi.eu/andrea/testhub
+module git.andreafazzi.eu/andrea/probo
 
 go 1.17
 
+require github.com/sirupsen/logrus v1.8.1
+
 require (
-	github.com/google/uuid v1.3.0 // indirect
 	github.com/kr/pretty v0.2.1 // indirect
 	github.com/kr/text v0.1.0 // indirect
 	github.com/remogatto/prettytest v0.0.0-20200211072524-6d385e11dcb8 // indirect
-	github.com/sirupsen/logrus v1.8.1 // indirect
 	golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )
diff --git a/go.sum b/go.sum
index fe2dcf6..b0788f1 100644
--- a/go.sum
+++ b/go.sum
@@ -1,6 +1,4 @@
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
-github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
diff --git a/hasher/hasher.go b/hasher/hasher.go
new file mode 100644
index 0000000..9dbaba3
--- /dev/null
+++ b/hasher/hasher.go
@@ -0,0 +1,26 @@
+package hasher
+
+import (
+	"git.andreafazzi.eu/andrea/probo/client"
+)
+
+type HashFunc func(string) string
+
+type Hasher interface {
+	// Hash returns a slice of hashes. The first one is an
+	// hash calculated from the question using
+	// QuestionHash. Following hashes are calculated from the
+	// answers using AnswerHash.
+	QuizHashes(quiz *client.CreateQuizRequest) []string
+
+	// QuestionHash returns an hash calculated from a field of
+	// Question struct.
+	QuestionHash(question *client.CreateQuestionRequest) string
+
+	// AnswerHash returns an hash calculated from a field of
+	// Answer struct.
+	AnswerHash(answer *client.CreateAnswerRequest) string
+
+	// Calculate calculates a checksum from all the given hashes.
+	Calculate(hashes []string) string
+}
diff --git a/hasher/hasher_test.go b/hasher/hasher_test.go
new file mode 100644
index 0000000..6662224
--- /dev/null
+++ b/hasher/hasher_test.go
@@ -0,0 +1,64 @@
+package hasher
+
+import (
+	"testing"
+
+	"git.andreafazzi.eu/andrea/probo/client"
+	"github.com/remogatto/prettytest"
+)
+
+type testSuite struct {
+	prettytest.Suite
+}
+
+func TestRunner(t *testing.T) {
+	prettytest.Run(
+		t,
+		new(testSuite),
+	)
+}
+
+func (t *testSuite) TestQuizHashes() {
+	h := NewDefaultHash(DefaultSHA256HashingFn)
+
+	firstQuizRequest := &client.CreateQuizRequest{
+		Question: &client.CreateQuestionRequest{
+			Text: "Question 1"},
+		Answers: []*client.CreateAnswerRequest{
+			{Text: "Answer 2", Correct: false},
+			{Text: "Answer 3", Correct: false},
+			{Text: "Answer 1", Correct: true},
+		},
+	}
+
+	secondQuizRequest := &client.CreateQuizRequest{
+		Question: &client.CreateQuestionRequest{
+			Text: "Question 1"},
+		Answers: []*client.CreateAnswerRequest{
+			{Text: "Answer 1", Correct: false},
+			{Text: "Answer 2", Correct: false},
+			{Text: "Answer 3", Correct: true},
+		},
+	}
+
+	thirdQuizRequest := &client.CreateQuizRequest{
+		Question: &client.CreateQuestionRequest{
+			Text: "Question 2"},
+		Answers: []*client.CreateAnswerRequest{
+			{Text: "Answer 1", Correct: false},
+			{Text: "Answer 2", Correct: false},
+			{Text: "Answer 3", Correct: true},
+		},
+	}
+
+	hashesFromFirstRequest := h.QuizHashes(firstQuizRequest)
+	hashesFromSecondRequest := h.QuizHashes(secondQuizRequest)
+	hashesFromThirdRequest := h.QuizHashes(thirdQuizRequest)
+
+	t.Equal(5, len(hashesFromFirstRequest))
+
+	t.True(hashesFromFirstRequest[1] == hashesFromSecondRequest[2], "Answers' hashes should maintain original request's order")
+	t.True(hashesFromFirstRequest[4] == hashesFromSecondRequest[4], "Quiz hash should be the same because quizzes are duplicated")
+	t.True(hashesFromFirstRequest[1] != hashesFromThirdRequest[1], "Questions' hashes should not be the same because texts are different")
+	t.True(hashesFromFirstRequest[4] != hashesFromThirdRequest[4], "Quiz hash should not be the same because quizzes are not duplicated")
+}
diff --git a/hasher/sha256/sha256.go b/hasher/sha256/sha256.go
new file mode 100644
index 0000000..8a9310f
--- /dev/null
+++ b/hasher/sha256/sha256.go
@@ -0,0 +1,54 @@
+package sha256
+
+import (
+	"crypto/sha256"
+	"fmt"
+	"sort"
+	"strings"
+
+	"git.andreafazzi.eu/andrea/probo/client"
+	"git.andreafazzi.eu/andrea/probo/hasher"
+)
+
+var DefaultSHA256HashingFn = func(text string) string {
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(text)))
+}
+
+type Default256Hasher struct {
+	hashFn hasher.HashFunc
+}
+
+func NewDefault256Hasher(hashFn hasher.HashFunc) *Default256Hasher {
+	return &Default256Hasher{hashFn}
+}
+
+func (h *Default256Hasher) QuizHashes(quiz *client.CreateQuizRequest) []string {
+	result := make([]string, 0)
+
+	result = append(result, h.QuestionHash(quiz.Question))
+
+	for _, a := range quiz.Answers {
+		result = append(result, h.AnswerHash(a))
+	}
+
+	result = append(result, h.Calculate(result))
+
+	return result
+}
+
+func (h *Default256Hasher) QuestionHash(question *client.CreateQuestionRequest) string {
+	return h.hashFn(question.Text)
+}
+
+func (h *Default256Hasher) AnswerHash(answer *client.CreateAnswerRequest) string {
+	return h.hashFn(answer.Text)
+}
+
+func (h *Default256Hasher) Calculate(hashes []string) string {
+	orderedHashes := make([]string, len(hashes))
+
+	copy(orderedHashes, hashes)
+	sort.Strings(orderedHashes)
+
+	return h.hashFn(strings.Join(orderedHashes, ""))
+}
diff --git a/main.go b/main.go
index e92f090..b5822dc 100644
--- a/main.go
+++ b/main.go
@@ -4,8 +4,9 @@ import (
 	"log"
 	"net/http"
 
-	"git.andreafazzi.eu/andrea/testhub/logger"
-	"git.andreafazzi.eu/andrea/testhub/store"
+	"git.andreafazzi.eu/andrea/probo/hasher/sha256"
+	"git.andreafazzi.eu/andrea/probo/logger"
+	"git.andreafazzi.eu/andrea/probo/store/memory"
 	"github.com/sirupsen/logrus"
 )
 
@@ -14,10 +15,14 @@ const port = "3000"
 func main() {
 	logger.SetLevel(logger.DebugLevel)
 
-	server := NewQuizHubCollectorServer(store.NewMemoryQuizHubCollectorStore())
+	server := NewQuizHubCollectorServer(
+		memory.NewMemoryQuizHubCollectorStore(
+			sha256.NewDefault256Hasher(sha256.DefaultSHA256HashingFn),
+		),
+	)
 
-	addr := "localhost:" + port
-	logrus.WithField("addr", addr).Info("TestHub Collector server is listening.")
+	addr := "http://localhost:" + port
+	logrus.WithField("address", addr).Info("Probo Collector is up&running...")
 
 	log.Fatal(http.ListenAndServe(":"+port, server))
 }
diff --git a/models/test.go b/models/test.go
index 077374f..f811006 100644
--- a/models/test.go
+++ b/models/test.go
@@ -1,7 +1,7 @@
 package models
 
 type Quiz struct {
-	ID uint
+	ID string
 
 	Question *Question
 	Answers  []*Answer
diff --git a/server.go b/server.go
index ee4b83e..c68645e 100644
--- a/server.go
+++ b/server.go
@@ -5,10 +5,10 @@ import (
 	"io/ioutil"
 	"net/http"
 
-	"git.andreafazzi.eu/andrea/testhub/client"
-	"git.andreafazzi.eu/andrea/testhub/logger"
-	"git.andreafazzi.eu/andrea/testhub/models"
-	"git.andreafazzi.eu/andrea/testhub/store"
+	"git.andreafazzi.eu/andrea/probo/client"
+	"git.andreafazzi.eu/andrea/probo/logger"
+	"git.andreafazzi.eu/andrea/probo/models"
+	"git.andreafazzi.eu/andrea/probo/store"
 )
 
 const jsonContentType = "application/json"
@@ -38,8 +38,17 @@ func (ps *QuizHubCollectorServer) testHandler(w http.ResponseWriter, r *http.Req
 		json.NewEncoder(w).Encode(ps.readAllQuizzes(w, r))
 
 	case http.MethodPost:
+		response := new(client.Response)
+
+		quiz, err := ps.createQuiz(w, r)
+		if err != nil {
+			response = &client.Response{Status: "error", Content: err.Error()}
+		}
+
+		response = &client.Response{Status: "success", Content: quiz}
+
 		w.WriteHeader(http.StatusAccepted)
-		json.NewEncoder(w).Encode(ps.createQuiz(w, r))
+		json.NewEncoder(w).Encode(response)
 	}
 }
 
@@ -51,18 +60,23 @@ func (ps *QuizHubCollectorServer) readAllQuizzes(w http.ResponseWriter, r *http.
 	return &client.Response{Status: "success", Content: tests}
 }
 
-func (ps *QuizHubCollectorServer) createQuiz(w http.ResponseWriter, r *http.Request) *models.Quiz {
+func (ps *QuizHubCollectorServer) createQuiz(w http.ResponseWriter, r *http.Request) (*models.Quiz, error) {
 	body, err := ioutil.ReadAll(r.Body)
 	if err != nil {
-		panic(err)
+		return nil, err
 	}
+
 	createQuizReq := new(client.CreateQuizRequest)
+
 	err = json.Unmarshal(body, &createQuizReq)
 	if err != nil {
-		panic(err)
+		return nil, err
 	}
 
-	createdQuiz := ps.store.CreateQuiz(createQuizReq)
+	createdQuiz, err := ps.store.CreateQuiz(createQuizReq)
+	if err != nil {
+		return nil, err
+	}
 
-	return createdQuiz
+	return createdQuiz, nil
 }
diff --git a/server_integration_test.go b/server_integration_test.go
index 102d92e..df1d00e 100644
--- a/server_integration_test.go
+++ b/server_integration_test.go
@@ -4,11 +4,12 @@ import (
 	"encoding/json"
 	"net/http"
 	"net/http/httptest"
+	"reflect"
 	"strings"
 
-	"git.andreafazzi.eu/andrea/testhub/client"
-	"git.andreafazzi.eu/andrea/testhub/models"
-	"git.andreafazzi.eu/andrea/testhub/store"
+	"git.andreafazzi.eu/andrea/probo/client"
+	"git.andreafazzi.eu/andrea/probo/hasher/sha256"
+	"git.andreafazzi.eu/andrea/probo/store/memory"
 	"github.com/remogatto/prettytest"
 )
 
@@ -17,7 +18,11 @@ type integrationTestSuite struct {
 }
 
 func (t *integrationTestSuite) TestQuizCreateAndReadAll() {
-	server := NewQuizHubCollectorServer(store.NewMemoryQuizHubCollectorStore())
+	server := NewQuizHubCollectorServer(
+		memory.NewMemoryQuizHubCollectorStore(
+			sha256.NewDefault256Hasher(sha256.DefaultSHA256HashingFn),
+		),
+	)
 
 	// POST a new question using a JSON payload
 
@@ -32,38 +37,80 @@ func (t *integrationTestSuite) TestQuizCreateAndReadAll() {
   ]
 }
 `
+	createQuizResponse, err := t.createQuiz(server, payload)
+	t.True(err == nil)
+
+	t.Equal("success", createQuizResponse.Status)
+	t.Equal("Question 1", createQuizResponse.Content.Question.Text)
+	t.Equal("Text of the answer 1", createQuizResponse.Content.Answers[0].Text)
+	t.Equal("Text of the answer 1", createQuizResponse.Content.Correct.Text)
+
+	t.True(createQuizResponse.Content.ID != "", "Test ID should not be empty")
+	t.True(createQuizResponse.Content.Question.ID != "", "Question ID should not be empty")
+	t.True(createQuizResponse.Content.Answers[0].ID != "", "Answer ID should not be empty")
+
+	readAllQuizResponse, err := t.readAllQuiz(server)
+	t.True(err == nil)
+
+	t.True(len(readAllQuizResponse.Content) == 1, "Length of returned tests should be 1")
+	t.Equal("Question 1", readAllQuizResponse.Content[0].Question.Text)
+}
+
+func (t *integrationTestSuite) TestCatchDuplicateQuiz() {
+	server := NewQuizHubCollectorServer(
+		memory.NewMemoryQuizHubCollectorStore(
+			sha256.NewDefault256Hasher(sha256.DefaultSHA256HashingFn),
+		),
+	)
+
+	// POST a new question using a JSON payload
+
+	payload := `
+{
+  "question": {"text": "Question 1"},
+  "answers": [
+    {"text": "Text of the answer 1", "correct": true},
+    {"text": "Text of the answer 2"},
+    {"text": "Text of the answer 3"},
+    {"text": "Text of the answer 4"}
+  ]
+}
+`
+	quiz1, err := t.createQuiz(server, payload)
+	t.True(err == nil)
+	quiz2, err := t.createQuiz(server, payload)
+	t.True(err == nil, "Quiz are duplicated, but the API should not return an error")
+	t.True(reflect.DeepEqual(quiz1, quiz2))
+}
+
+func (t *integrationTestSuite) createQuiz(server *QuizHubCollectorServer, payload string) (*client.CreateQuizResponse, error) {
 	request, _ := http.NewRequest(http.MethodPost, "/quizzes", strings.NewReader(payload))
 	response := httptest.NewRecorder()
 
 	server.ServeHTTP(response, request)
 
-	returnedTest := new(models.Quiz)
+	decodedResponse := new(client.CreateQuizResponse)
 
-	err := json.Unmarshal(response.Body.Bytes(), returnedTest)
+	err := json.Unmarshal(response.Body.Bytes(), decodedResponse)
 	if err != nil {
-		t.True(err == nil, err.Error())
+		return nil, err
 	}
 
-	t.Equal("Question 1", returnedTest.Question.Text)
-	t.Equal("Text of the answer 1", returnedTest.Answers[0].Text)
-	t.Equal("Text of the answer 1", returnedTest.Correct.Text)
+	return decodedResponse, err
+}
 
-	t.True(returnedTest.ID != 0, "Test ID should not be 0")
-	t.True(returnedTest.Question.ID != "", "Question ID should not be empty")
-	t.True(returnedTest.Answers[0].ID != "", "Answer ID should not be empty")
-
-	request, _ = http.NewRequest(http.MethodGet, "/quizzes", nil)
-	response = httptest.NewRecorder()
+func (t *integrationTestSuite) readAllQuiz(server *QuizHubCollectorServer) (*client.ReadAllQuizResponse, error) {
+	request, _ := http.NewRequest(http.MethodGet, "/quizzes", nil)
+	response := httptest.NewRecorder()
 
 	server.ServeHTTP(response, request)
 
-	decodedResponse := new(client.QuizReadAllResponse)
+	decodedResponse := new(client.ReadAllQuizResponse)
 
-	err = json.Unmarshal(response.Body.Bytes(), &decodedResponse)
+	err := json.Unmarshal(response.Body.Bytes(), decodedResponse)
 	if err != nil {
-		t.True(err == nil, err.Error())
+		return nil, err
 	}
 
-	t.True(len(decodedResponse.Content) == 1, "Length of returned tests should be 1")
-	t.Equal("Question 1", decodedResponse.Content[0].Question.Text)
+	return decodedResponse, err
 }
diff --git a/server_test.go b/server_test.go
index d2d0a39..ac838de 100644
--- a/server_test.go
+++ b/server_test.go
@@ -9,9 +9,9 @@ import (
 	"reflect"
 	"testing"
 
-	"git.andreafazzi.eu/andrea/testhub/client"
-	"git.andreafazzi.eu/andrea/testhub/logger"
-	"git.andreafazzi.eu/andrea/testhub/models"
+	"git.andreafazzi.eu/andrea/probo/client"
+	"git.andreafazzi.eu/andrea/probo/logger"
+	"git.andreafazzi.eu/andrea/probo/models"
 	"github.com/remogatto/prettytest"
 )
 
@@ -23,8 +23,8 @@ type StubTestHubCollectorStore struct {
 	tests []*models.Quiz
 }
 
-func (store *StubTestHubCollectorStore) CreateQuiz(test *client.CreateQuizRequest) *models.Quiz {
-	return nil
+func (store *StubTestHubCollectorStore) CreateQuiz(test *client.CreateQuizRequest) (*models.Quiz, error) {
+	return nil, nil
 }
 
 func (store *StubTestHubCollectorStore) ReadAllQuizzes() ([]*models.Quiz, error) {
@@ -44,7 +44,7 @@ func (t *testSuite) BeforeAll() {
 }
 
 func (t *testSuite) TestGETQuestions() {
-	expectedResult := &client.QuizReadAllResponse{
+	expectedResult := &client.ReadAllQuizResponse{
 		Status: "success",
 		Content: []*models.Quiz{
 			{
@@ -76,7 +76,7 @@ func (t *testSuite) TestGETQuestions() {
 	t.Equal(http.StatusOK, response.Code)
 }
 
-func getResponse(body io.Reader) (response *client.QuizReadAllResponse) {
+func getResponse(body io.Reader) (response *client.ReadAllQuizResponse) {
 	err := json.NewDecoder(body).Decode(&response)
 	if err != nil {
 		panic(fmt.Errorf("Unable to parse response from server %q into slice of Test, '%v'", body, err))
@@ -85,6 +85,6 @@ func getResponse(body io.Reader) (response *client.QuizReadAllResponse) {
 	return
 }
 
-func testsAreEqual(got, want *client.QuizReadAllResponse) bool {
+func testsAreEqual(got, want *client.ReadAllQuizResponse) bool {
 	return reflect.DeepEqual(got, want)
 }
diff --git a/store/memory.go b/store/memory.go
deleted file mode 100644
index 5509898..0000000
--- a/store/memory.go
+++ /dev/null
@@ -1,81 +0,0 @@
-package store
-
-import (
-	"crypto/sha256"
-	"fmt"
-	"sync"
-
-	"git.andreafazzi.eu/andrea/testhub/client"
-	"git.andreafazzi.eu/andrea/testhub/models"
-)
-
-type MemoryQuizHubCollectorStore struct {
-	questions  map[string]*models.Question
-	answers    map[string]*models.Answer
-	tests      map[uint]*models.Quiz
-	lastQuizID uint
-
-	questionAnswer map[string][]string
-	testQuestion   map[string]uint
-
-	// A mutex is used to synchronize read/write access to the map
-	lock sync.RWMutex
-}
-
-func NewMemoryQuizHubCollectorStore() *MemoryQuizHubCollectorStore {
-	s := new(MemoryQuizHubCollectorStore)
-
-	s.questions = make(map[string]*models.Question)
-	s.answers = make(map[string]*models.Answer)
-	s.tests = make(map[uint]*models.Quiz)
-
-	return s
-}
-
-func (s *MemoryQuizHubCollectorStore) ReadAllQuizzes() ([]*models.Quiz, error) {
-	result := make([]*models.Quiz, 0)
-	for _, t := range s.tests {
-		result = append(result, t)
-	}
-	return result, nil
-}
-
-func (s *MemoryQuizHubCollectorStore) CreateQuiz(r *client.CreateQuizRequest) *models.Quiz {
-	questionID := hash(r.Question.Text)
-	test := new(models.Quiz)
-	q, ok := s.questions[questionID]
-	if !ok { // if the question is not in the store add it
-		s.questions[questionID] = &models.Question{
-			ID:   questionID,
-			Text: r.Question.Text,
-		}
-		q = s.questions[questionID]
-	}
-	// Populate Question field
-	test.Question = q
-	for _, answer := range r.Answers {
-		// Calculate the hash from text
-		answerID := hash(answer.Text)
-		_, ok := s.answers[answerID]
-		if !ok { // if the answer is not in the store add it
-			s.answers[answerID] = &models.Answer{
-				ID:   answerID,
-				Text: answer.Text,
-			}
-		}
-		if answer.Correct {
-			test.Correct = s.answers[answerID]
-		}
-		test.Answers = append(test.Answers, s.answers[answerID])
-	}
-
-	s.lastQuizID++
-	test.ID = s.lastQuizID
-	s.tests[s.lastQuizID] = test
-
-	return test
-}
-
-func hash(text string) string {
-	return fmt.Sprintf("%x", sha256.Sum256([]byte(text)))
-}
diff --git a/store/memory/memory.go b/store/memory/memory.go
new file mode 100644
index 0000000..166ff5d
--- /dev/null
+++ b/store/memory/memory.go
@@ -0,0 +1,147 @@
+package memory
+
+import (
+	"sync"
+
+	"git.andreafazzi.eu/andrea/probo/client"
+	"git.andreafazzi.eu/andrea/probo/hasher"
+	"git.andreafazzi.eu/andrea/probo/models"
+)
+
+type MemoryQuizHubCollectorStore struct {
+	questions map[string]*models.Question
+	answers   map[string]*models.Answer
+	quizzes   map[string]*models.Quiz
+
+	questionAnswer map[string][]string
+	testQuestion   map[string]uint
+
+	// A mutex is used to synchronize read/write access to the map
+	lock sync.RWMutex
+
+	hasher hasher.Hasher
+}
+
+func NewMemoryQuizHubCollectorStore(hasher hasher.Hasher) *MemoryQuizHubCollectorStore {
+	s := new(MemoryQuizHubCollectorStore)
+
+	s.hasher = hasher
+	s.questions = make(map[string]*models.Question)
+	s.answers = make(map[string]*models.Answer)
+	s.quizzes = make(map[string]*models.Quiz)
+
+	return s
+}
+
+func (s *MemoryQuizHubCollectorStore) readQuiz(id string) *models.Quiz {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	quiz, ok := s.quizzes[id]
+	if ok {
+		return quiz
+	}
+
+	return nil
+}
+
+func (s *MemoryQuizHubCollectorStore) readQuestion(id string) *models.Question {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	question, ok := s.questions[id]
+	if ok {
+		return question
+	}
+
+	return nil
+}
+
+func (s *MemoryQuizHubCollectorStore) readAnswer(id string) *models.Answer {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	answer, ok := s.answers[id]
+	if ok {
+		return answer
+	}
+
+	return nil
+}
+
+func (s *MemoryQuizHubCollectorStore) createQuiz(id string, quiz *models.Quiz) *models.Quiz {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	quiz.ID = id
+	s.quizzes[id] = quiz
+
+	return quiz
+}
+
+func (s *MemoryQuizHubCollectorStore) createQuestion(id string, question *models.Question) *models.Question {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.questions[id] = question
+
+	return question
+}
+
+func (s *MemoryQuizHubCollectorStore) createAnswer(id string, answer *models.Answer) *models.Answer {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.answers[id] = answer
+
+	return answer
+}
+
+func (s *MemoryQuizHubCollectorStore) ReadAllQuizzes() ([]*models.Quiz, error) {
+	result := make([]*models.Quiz, 0)
+	for id, _ := range s.quizzes {
+		result = append(result, s.readQuiz(id))
+	}
+	return result, nil
+}
+
+func (s *MemoryQuizHubCollectorStore) CreateQuiz(r *client.CreateQuizRequest) (*models.Quiz, error) {
+	hashes := s.hasher.QuizHashes(r)
+
+	quizID := hashes[len(hashes)-1]
+
+	quiz := s.readQuiz(quizID)
+	if quiz != nil { // Quiz is already present in the store
+		return quiz, nil
+	}
+
+	quiz = new(models.Quiz)
+
+	questionID := hashes[0]
+	q := s.readQuestion(questionID)
+	if q == nil { // if the question is not in the store add it
+		q = s.createQuestion(questionID, &models.Question{
+			ID:   questionID,
+			Text: r.Question.Text,
+		})
+	}
+
+	// Populate Question field
+	quiz.Question = q
+	for i, answer := range r.Answers {
+		answerID := hashes[i+1]
+		a := s.readAnswer(answerID)
+		if a == nil { // if the answer is not in the store add it
+			a = s.createAnswer(answerID, &models.Answer{
+				ID:   answerID,
+				Text: answer.Text,
+			})
+			if answer.Correct {
+				quiz.Correct = a // s.readAnswer(answerID)
+			}
+		}
+		quiz.Answers = append(quiz.Answers, a)
+	}
+
+	return s.createQuiz(quizID, quiz), nil
+}
diff --git a/store/store.go b/store/store.go
index dfdbd96..1fc4c72 100644
--- a/store/store.go
+++ b/store/store.go
@@ -1,11 +1,11 @@
 package store
 
 import (
-	"git.andreafazzi.eu/andrea/testhub/client"
-	"git.andreafazzi.eu/andrea/testhub/models"
+	"git.andreafazzi.eu/andrea/probo/client"
+	"git.andreafazzi.eu/andrea/probo/models"
 )
 
 type QuizHubCollectorStore interface {
 	ReadAllQuizzes() ([]*models.Quiz, error)
-	CreateQuiz(r *client.CreateQuizRequest) *models.Quiz
+	CreateQuiz(r *client.CreateQuizRequest) (*models.Quiz, error)
 }