diff --git a/application/core/LSSodium.php b/application/core/LSSodium.php
index 48342188c54..f09d2480300 100644
--- a/application/core/LSSodium.php
+++ b/application/core/LSSodium.php
@@ -115,7 +115,7 @@ protected function getEncryptionSecretKey()
     public function encrypt($sDataToEncrypt): string
     {
         if ($this->bLibraryExists === true) {
-            if ($sDataToEncrypt) {
+            if (isset($sDataToEncrypt) && $sDataToEncrypt !== "") {
                 $sEncrypted = base64_encode(ParagonIE_Sodium_Compat::crypto_secretbox((string) $sDataToEncrypt, $this->sEncryptionNonce, $this->sEncryptionSecretBoxKey));
                 return $sEncrypted;
             }
@@ -127,7 +127,7 @@ public function encrypt($sDataToEncrypt): string
     /**
      *
      * Decrypt encrypted string.
-     * @param string $sEncryptedString Encrypted string to decrypt
+     * @param string $sEncryptedString Encrypted string to decrypt, if it string 'null', didn't try to decode
      * @param bool $bReturnFalseIfError false by default. If TRUE, return false in case of error (bad decryption). Else, return given $encryptedInput value
      * @return string Return decrypted value (string or unsezialized object) if suceeded. Return FALSE if an error occurs (bad password/salt given) or inpyt encryptedString
      * @throws SodiumException
diff --git a/application/models/LSActiveRecord.php b/application/models/LSActiveRecord.php
index d27e7196029..e58a57a9cff 100644
--- a/application/models/LSActiveRecord.php
+++ b/application/models/LSActiveRecord.php
@@ -399,7 +399,7 @@ public static function decryptSingleOld($value = ''): string
             $sodium = Yii::app()->sodiumOld;
         }
         // if $value is provided, it would decrypt
-        if ($value) {
+        if (isset($value) && $value !== '') {
             try {
                 return $sodium->decrypt($value);
             } catch (throwable $e) {
@@ -424,7 +424,7 @@ public static function decryptSingleOld($value = ''): string
     public static function encryptSingle($value = '')
     {
         // if $value is provided, it would decrypt
-        if (!empty($value)) {
+        if (isset($value) && $value !== "") {
             // load sodium library
             $sodium = Yii::app()->sodium;
             return $sodium->encrypt($value);
@@ -458,7 +458,6 @@ public function encryptSave($runValidation = false)
 
         // encrypt attributes
         $this->decryptEncryptAttributes('encrypt');
-
         // call save() method  without validation, validation is already done ( if needed )
         return $this->save(false);
     }
diff --git a/tests/unit/models/EncryptAttributesTest.php b/tests/unit/models/EncryptAttributesTest.php
index 3de704e84d3..624fb58b870 100644
--- a/tests/unit/models/EncryptAttributesTest.php
+++ b/tests/unit/models/EncryptAttributesTest.php
@@ -20,7 +20,7 @@ public static function setupBeforeClass(): void
         $surveyFile = self::$surveysFolder . '/survey_archive_265831.lsa';
         self::importSurvey($surveyFile);
     }
-    
+
     /**
      * Test token without validation.
      */
@@ -52,6 +52,69 @@ public function testTokenWithoutValidation()
         $this->assertNotEquals('last', $token->lastname);
     }
 
+    /**
+     * Test token with 0 as value
+     * No validation
+     */
+    public function testTokenCrypt0()
+    {
+        // Get our token.
+        $tokens = \TokenDynamic::model(self::$surveyId)->findAll();
+        $this->assertNotEmpty($tokens);
+        $this->assertCount(1, $tokens);
+        $token = $tokens[0];
+        $token->decrypt();
+
+        // Change attribute_1.
+        $token->attribute_1 = '0';
+        $token->encryptSave(false);
+
+        // Load token and decrypt.
+        $tokens = \TokenDynamic::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $tokens);
+        $token = $tokens[0];
+        $token->decrypt();
+        $this->assertEquals('0', $token->attribute_1);
+
+        // Test the omitting decrypt() works.
+        $tokens = \TokenDynamic::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $tokens);
+        $token = $tokens[0];
+        $this->assertNotEquals('0', $token->attribute_1);
+    }
+
+    /**
+     * Test token with "" as value
+     * No validation
+     */
+    public function testTokenCryptEmptyString()
+    {
+        // Get our token.
+        $tokens = \TokenDynamic::model(self::$surveyId)->findAll();
+        $this->assertNotEmpty($tokens);
+        $this->assertCount(1, $tokens);
+        $token = $tokens[0];
+        $token->decrypt();
+
+        // Change attribute_1.
+        $token->attribute_1 = '';
+        $token->encryptSave(false);
+
+        // Load token and decrypt.
+        $tokens = \TokenDynamic::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $tokens);
+        $token = $tokens[0];
+        $token->decrypt();
+        $this->assertEquals('', $token->attribute_1);
+
+        // Test the omitting decrypt works : "" is not cryted
+        $tokens = \TokenDynamic::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $tokens);
+        $token = $tokens[0];
+        /* "" is not crypted */
+        $this->assertEquals('', $token->attribute_1);
+    }
+
     /**
      * Test token with validation.
      */
@@ -156,4 +219,81 @@ public function testResponseWithValidation()
         $this->assertEquals('New answer.', $decryptedAnswer);
         $this->assertNotEquals('New answer.', $answer);
     }
+
+    /**
+     * Test response savec with 0
+     * With validation
+     */
+    public function testResponseCrypt0()
+    {
+        $responses = \Response::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $responses);
+        $response = $responses[0];
+        $response->decrypt();
+
+        // Get questions.
+        $survey = \Survey::model()->findByPk(self::$surveyId);
+        $questionObjects = $survey->groups[0]->questions;
+        $questions = [];
+        foreach ($questionObjects as $q) {
+            $questions[$q->title] = $q;
+        }
+
+        $sgqa = self::$surveyId . 'X' . $survey->groups[0]->gid . 'X' . $questions['Q00']->qid;
+
+        // Change answer
+        $response->$sgqa = "0";
+        $response->encryptSave(true);
+
+        // Load answer
+        $responses = \Response::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $responses);
+        $response = $responses[0];
+
+        $answer = $response->$sgqa;
+        $response->decrypt();
+        $decryptedAnswer = $response->$sgqa;
+
+        $this->assertEquals('0', $decryptedAnswer);
+        $this->assertNotEquals('0', $answer);
+    }
+
+    /**
+     * Test response saved with ""
+     * With validation
+     */
+    public function testResponseCryptEmptyString()
+    {
+        $responses = \Response::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $responses);
+        $response = $responses[0];
+        $response->decrypt();
+
+        // Get questions.
+        $survey = \Survey::model()->findByPk(self::$surveyId);
+        $questionObjects = $survey->groups[0]->questions;
+        $questions = [];
+        foreach ($questionObjects as $q) {
+            $questions[$q->title] = $q;
+        }
+
+        $sgqa = self::$surveyId . 'X' . $survey->groups[0]->gid . 'X' . $questions['Q00']->qid;
+
+        // Change answer
+        $response->$sgqa = "";
+        $response->encryptSave(true);
+
+        // Load answer
+        $responses = \Response::model(self::$surveyId)->findAll();
+        $this->assertCount(1, $responses);
+        $response = $responses[0];
+
+        $answer = $response->$sgqa;
+        $response->decrypt();
+        $decryptedAnswer = $response->$sgqa;
+
+        $this->assertEquals('', $decryptedAnswer);
+        /* "" is not crypted */
+        $this->assertEquals('', $answer);
+    }
 }