diff --git a/admin/api/exercice.go b/admin/api/exercice.go
index 2a1fb275..a1ab5153 100644
--- a/admin/api/exercice.go
+++ b/admin/api/exercice.go
@@ -332,7 +332,15 @@ func updateExerciceFlag(flag fic.FlagKey, exercice fic.Exercice, body []byte) (i
 
 	flag.Help = uk.Help
 	flag.IgnoreCase = uk.IgnoreCase
-	flag.Checksum = uk.Value
+	if len(uk.Flag) > 0 {
+		var err error
+		flag.Checksum, err = flag.ComputeChecksum([]byte(uk.Flag))
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		flag.Checksum = uk.Value
+	}
 	flag.ChoicesCost = uk.ChoicesCost
 
 	if uk.ValidatorRe != nil && len(*uk.ValidatorRe) > 0 {
diff --git a/admin/static/js/app.js b/admin/static/js/app.js
index f9d06cc5..61967cae 100644
--- a/admin/static/js/app.js
+++ b/admin/static/js/app.js
@@ -1341,6 +1341,10 @@ angular.module("FICApp")
     .controller("ExerciceFlagsController", function($scope, ExerciceFlag, $routeParams, $rootScope, $http) {
 	$scope.flags = ExerciceFlag.query({ exerciceId: $routeParams.exerciceId });
 
+	$scope.changeValue = function(flag) {
+	    flag.value = undefined;
+	    flag.show_raw = true;
+	}
 	$scope.addFlag = function() {
 	    $scope.flags.push(new ExerciceFlag());
 	}
diff --git a/admin/static/views/exercice.html b/admin/static/views/exercice.html
index e9438d29..ae4fd3c8 100644
--- a/admin/static/views/exercice.html
+++ b/admin/static/views/exercice.html
@@ -126,8 +126,13 @@
 	      </div>
 	    </div>
 	    <div class="row">
-	      <input type="text" id="kvalue{{flag.id}}" ng-model="flag.value" class="col form-control form-control-sm" placeholder="Condensat" ng-if="flag.id" title="Condensat">
-	      <input type="text" id="kflag{{flag.id}}" ng-model="flag.flag" class="col form-control form-control-sm" placeholder="Chaîne brute à valider" ng-if="!flag.id" title="Chaîne brute à valider">
+	      <div class="col input-group" ng-if="flag.id && !flag.show_raw" style="padding:0">
+		<input type="text" id="kvalue{{flag.id}}" ng-model="flag.value" class="form-control form-control-sm" placeholder="Condensat" title="Condensat">
+		<div class="input-group-append">
+		  <button class="btn btn-sm btn-outline-secondary" ng-click="changeValue(flag)" title="Cliquez pour éditer la valeur brute du flag, au lieu du checksum" type="button"><span class="glyphicon glyphicon-erase" aria-hidden="true"></span></button>
+		</div>
+	      </div>
+	      <input type="text" id="kflag{{flag.id}}" ng-model="flag.flag" class="col form-control form-control-sm" placeholder="Chaîne brute à valider" ng-if="!flag.id || flag.show_raw" title="Chaîne brute à valider">
 	      <div class="col-auto custom-control custom-checkbox ml-1">
 		<input type="checkbox" class="custom-control-input" id="kicase{{flag.id}}" ng-model="flag.ignorecase">
 		<label class="custom-control-label" for="kicase{{flag.id}}">Ignore case</label>
@@ -138,8 +143,8 @@
 	    </div>
 	    </form>
 	    <form ng-submit="testFlag(flag)">
-	      <div class="input-group">
-		<input type="text" id="ktest{{flag.id}}" ng-model="flag.test_str" class="col form-control form-control-sm" placeholder="Test the flag">
+	      <div class="input-group row">
+		<input type="text" id="ktest{{flag.id}}" ng-model="flag.test_str" class="form-control form-control-sm" placeholder="Test the flag">
 		<div class="input-group-append">
 		  <button class="btn btn-sm btn-warning" type="submit"><span class="glyphicon glyphicon-play" aria-hidden="true"></span></button>
 		</div>
diff --git a/libfic/flag_key.go b/libfic/flag_key.go
index 08e22737..c31c8ac7 100644
--- a/libfic/flag_key.go
+++ b/libfic/flag_key.go
@@ -119,6 +119,28 @@ func (e Exercice) AddFlagKey(name string, help string, ignorecase bool, validato
 	}
 }
 
+// SetChecksumFromValue .
+func (k FlagKey) ComputeChecksum(val []byte) (cksum []byte, err error) {
+	if k.IgnoreCase {
+		val = bytes.ToLower(val)
+	}
+
+	// Check that raw value passes through the regexp
+	if k.ValidatorRegexp != nil {
+		if val, err = ExecValidatorRegexp(*k.ValidatorRegexp, val); err != nil {
+			return
+		}
+	}
+
+	// Check that the value is not empty
+	if len(val) == 0 {
+		err = errors.New("Empty flag after applying filters")
+	}
+
+	hash := getHashedFlag(val)
+	return hash[:], err
+}
+
 // Update applies modifications back to the database.
 func (k FlagKey) Update() (int64, error) {
 	if k.ValidatorRegexp != nil {
@@ -220,21 +242,10 @@ func (k FlagKey) Check(v interface{}) int {
 		val = va
 	}
 
-	if k.IgnoreCase {
-		val = bytes.ToLower(val)
-	}
-
-	// Check that raw value passes through the regexp
-	if k.ValidatorRegexp != nil {
-		val, _ = ExecValidatorRegexp(*k.ValidatorRegexp, val)
-	}
-
-	// Check that the value is not empty
-	if len(val) == 0 {
+	hash, err := k.ComputeChecksum(val)
+	if err != nil {
 		return 1
 	}
-
-	hash := getHashedFlag(val)
 	if len(k.Checksum) != len(hash) {
 		return 1
 	}