diff --git a/admin/sync/exercice_defines.go b/admin/sync/exercice_defines.go
index 01f82fc3..33ce3949 100644
--- a/admin/sync/exercice_defines.go
+++ b/admin/sync/exercice_defines.go
@@ -20,18 +20,18 @@ type ExerciceDependency struct {
 	Theme string `toml:",omitempty"`
 }
 
+// ExerciceUnlockFile holds parameters related to a locked file.
+type ExerciceUnlockFile struct {
+	Filename string `toml:",omitempty"`
+}
+
 // ExerciceFlag holds informations about a "classic" flag.
 type ExerciceFlag struct {
 	Label      string `toml:",omitempty"`
 	Raw        string
-	IgnoreCase bool   `toml:",omitempty"`
-	Help       string `toml:",omitempty"`
-	LockedFile []ExerciceFlag `toml:unlock_file",omitempty"`
-}
-
-// ExerciceUnlockFile holds parameters related to a locked file.
-type ExerciceFlag struct {
-	Filename string `toml:",omitempty"`
+	IgnoreCase bool                 `toml:",omitempty"`
+	Help       string               `toml:",omitempty"`
+	LockedFile []ExerciceUnlockFile `toml:"unlock_file,omitempty"`
 }
 
 // ExerciceFlagMCQChoice holds a choice for an MCQ flag.
@@ -60,7 +60,7 @@ type ExerciceFlagUCQ struct {
 	DisplayAs    string `toml:",omitempty"`
 	Choices_Cost int64  `toml:",omitempty"`
 	Choice       []ExerciceFlagUCQChoice
-	LockedFile   []ExerciceFlag `toml:unlock_file",omitempty"`
+	LockedFile   []ExerciceUnlockFile `toml:"unlock_file,omitempty"`
 }
 
 // ExerciceParams contains values parsed from defines.txt.
diff --git a/admin/sync/exercice_keys.go b/admin/sync/exercice_keys.go
index 8ccadf9d..56f644a7 100644
--- a/admin/sync/exercice_keys.go
+++ b/admin/sync/exercice_keys.go
@@ -40,9 +40,20 @@ func SyncExerciceKeys(i Importer, exercice fic.Exercice) (errs []string) {
 				errs = append(errs, fmt.Sprintf("%q: WARNING flag #%d: non-printable characters in flag, is this really expected?", path.Base(exercice.Path), nline + 1))
 			}
 
-			if _, err := exercice.AddRawKey(flag.Label, flag.Raw); err != nil {
+			if k, err := exercice.AddRawKey(flag.Label, flag.Raw); err != nil {
 				errs = append(errs, fmt.Sprintf("%q: error flag #%d: %s", path.Base(exercice.Path), nline + 1, err))
 				continue
+			} else {
+				// Import dependency to file
+				for _, lf := range flag.LockedFile {
+					if rf, err := exercice.GetFileByFilename(lf.Filename); err != nil {
+						errs = append(errs, fmt.Sprintf("%q: error flag #%d dependency to %s: %s", path.Base(exercice.Path), nline + 1, lf.Filename, err))
+						continue
+					} else if err := rf.AddDepend(k); err != nil {
+						errs = append(errs, fmt.Sprintf("%q: error flag #%d dependency to %s: %s", path.Base(exercice.Path), nline + 1, lf.Filename, err))
+						continue
+					}
+				}
 			}
 		}
 
@@ -56,9 +67,20 @@ func SyncExerciceKeys(i Importer, exercice fic.Exercice) (errs []string) {
 				errs = append(errs, fmt.Sprintf("%q: WARNING flag UCQ #%d: non-printable characters in flag, is this really expected?", path.Base(exercice.Path), nline + 1))
 			}
 
-			if _, err := exercice.AddRawKey(flag.Label, flag.Raw); err != nil {
+			if k, err := exercice.AddRawKey(flag.Label, flag.Raw); err != nil {
 				errs = append(errs, fmt.Sprintf("%q: error flag UCQ #%d: %s", path.Base(exercice.Path), nline + 1, err))
 				continue
+			} else {
+				// Import dependency to file
+				for _, lf := range flag.LockedFile {
+					if rf, err := exercice.GetFileByFilename(lf.Filename); err != nil {
+						errs = append(errs, fmt.Sprintf("%q: error flag UCQ #%d dependency to %s: %s", path.Base(exercice.Path), nline + 1, lf.Filename, err))
+						continue
+					} else if err := rf.AddDepend(k); err != nil {
+						errs = append(errs, fmt.Sprintf("%q: error flag UCQ #%d dependency to %s: %s", path.Base(exercice.Path), nline + 1, lf.Filename, err))
+						continue
+					}
+				}
 			}
 		}
 
diff --git a/admin/sync/full.go b/admin/sync/full.go
index 0b5fb6ae..9d4c3128 100644
--- a/admin/sync/full.go
+++ b/admin/sync/full.go
@@ -34,9 +34,9 @@ func SyncDeep(i Importer) (errs map[string][]string) {
 
 			if exercices, err := theme.GetExercices(); err == nil {
 				for _, exercice := range exercices {
+					errs[theme.Name] = append(errs[theme.Name], SyncExerciceKeys(i, exercice)...)
 					errs[theme.Name] = append(errs[theme.Name], SyncExerciceFiles(i, exercice)...)
 					errs[theme.Name] = append(errs[theme.Name], SyncExerciceHints(i, exercice)...)
-					errs[theme.Name] = append(errs[theme.Name], SyncExerciceKeys(i, exercice)...)
 				}
 			}
 		}
diff --git a/libfic/db.go b/libfic/db.go
index 98eb202b..caebf16a 100644
--- a/libfic/db.go
+++ b/libfic/db.go
@@ -163,6 +163,16 @@ CREATE TABLE IF NOT EXISTS exercice_keys(
   cksum BINARY(64) NOT NULL,
   FOREIGN KEY(id_exercice) REFERENCES exercices(id_exercice)
 ) DEFAULT CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;
+`); err != nil {
+		return err
+	}
+	if _, err := db.Exec(`
+CREATE TABLE IF NOT EXISTS exercice_files_deps(
+  id_file INTEGER NOT NULL,
+  id_key INTEGER NOT NULL,
+  FOREIGN KEY(id_file) REFERENCES exercice_files(id_file),
+  FOREIGN KEY(id_key) REFERENCES exercice_keys(id_key)
+) DEFAULT CHARACTER SET = utf8 COLLATE = utf8_bin;
 `); err != nil {
 		return err
 	}
diff --git a/libfic/file.go b/libfic/file.go
index 35d6a983..a122fcb6 100644
--- a/libfic/file.go
+++ b/libfic/file.go
@@ -84,6 +84,15 @@ func GetFileByPath(path string) (EFile, error) {
 	return f, nil
 }
 
+// GetFileByFilename retrieves the file that should be called so.
+func (e Exercice) GetFileByFilename(filename string) (f EFile, err error) {
+	filename = path.Base(filename)
+
+	err = DBQueryRow("SELECT id_file, origin, path, id_exercice, name, cksum, size FROM exercice_files WHERE id_exercice = ? AND origin LIKE ?", e.Id, "%/" + filename).Scan(&f.Id, &f.origin, &f.Path, &f.IdExercice, &f.Name, &f.Checksum, &f.Size)
+
+	return
+}
+
 // GetFiles returns a list of files coming with the challenge.
 func (e Exercice) GetFiles() ([]EFile, error) {
 	if rows, err := DBQuery("SELECT id_file, origin, path, name, cksum, size FROM exercice_files WHERE id_exercice = ?", e.Id); err != nil {
@@ -262,6 +271,35 @@ func (f EFile) GetOrigin() string {
 	return f.origin
 }
 
+// AddDepend insert a new dependency to a given flag.
+func (f EFile) AddDepend(k Key) (err error) {
+	_, err = DBExec("INSERT INTO exercice_files_deps (id_file, id_key) VALUES (?, ?)", f.Id, k.Id)
+	return
+}
+
+// GetDepends retrieve the flag's dependency list.
+func (f EFile) GetDepends() ([]Key, error) {
+	if rows, err := DBQuery("SELECT id_key FROM exercice_files_deps WHERE id_file = ?", f.Id); err != nil {
+		return nil, err
+	} else {
+		defer rows.Close()
+
+		var deps = make([]Key, 0)
+		for rows.Next() {
+			var d int64
+			if err := rows.Scan(&d); err != nil {
+				return nil, err
+			}
+			deps = append(deps, Key{d, f.IdExercice, "", []byte{}})
+		}
+		if err := rows.Err(); err != nil {
+			return nil, err
+		}
+
+		return deps, nil
+	}
+}
+
 // CheckFileOnDisk recalculates the hash of the file on disk.
 func (f EFile) CheckFileOnDisk() error {
 	if _, size, err := checkFileHash(path.Join(FilesDir, f.Path), f.Checksum); err != nil {
diff --git a/libfic/key.go b/libfic/key.go
index 1ca9f470..ba7c52a4 100644
--- a/libfic/key.go
+++ b/libfic/key.go
@@ -79,7 +79,9 @@ func (k Key) Update() (int64, error) {
 
 // Delete the flag from the database.
 func (k Key) Delete() (int64, error) {
-	if res, err := DBExec("DELETE FROM exercice_keys WHERE id_key = ?", k.Id); err != nil {
+	if _, err := DBExec("DELETE FROM exercice_files_deps WHERE id_key = ?", k.Id); err != nil {
+		return 0, err
+	} else if res, err := DBExec("DELETE FROM exercice_keys WHERE id_key = ?", k.Id); err != nil {
 		return 0, err
 	} else if nb, err := res.RowsAffected(); err != nil {
 		return 0, err
@@ -90,7 +92,9 @@ func (k Key) Delete() (int64, error) {
 
 // WipeKeys deletes keys coming with the challenge.
 func (e Exercice) WipeKeys() (int64, error) {
-	if res, err := DBExec("DELETE FROM exercice_keys WHERE id_exercice = ?", e.Id); err != nil {
+	if _, err := DBExec("DELETE FROM exercice_files_deps WHERE id_key IN (SELECT id_key FROM exercice_keys WHERE id_exercice = ?)", e.Id); err != nil {
+		return 0, err
+	} else if res, err := DBExec("DELETE FROM exercice_keys WHERE id_exercice = ?", e.Id); err != nil {
 		return 0, err
 	} else if nb, err := res.RowsAffected(); err != nil {
 		return 0, err
diff --git a/libfic/reset.go b/libfic/reset.go
index cd1625e8..892b4c84 100644
--- a/libfic/reset.go
+++ b/libfic/reset.go
@@ -34,7 +34,7 @@ func ResetGame() (error) {
 
 // ResetExercices wipes out all challenges (both attempts and statements).
 func ResetExercices() (error) {
-	return truncateTable("team_hints", "exercice_files", "key_found", "exercice_keys", "exercice_solved", "exercice_tries", "exercice_hints", "mcq_found", "mcq_entries", "exercice_mcq", "exercices", "themes")
+	return truncateTable("team_hints", "exercice_files_deps", "exercice_files", "key_found", "exercice_keys", "exercice_solved", "exercice_tries", "exercice_hints", "mcq_found", "mcq_entries", "exercice_mcq", "exercices", "themes")
 }
 
 // ResetTeams wipes out all teams, incluings members and attempts.
diff --git a/libfic/team.go b/libfic/team.go
index d8568087..b7735e54 100644
--- a/libfic/team.go
+++ b/libfic/team.go
@@ -1,6 +1,7 @@
 package fic
 
 import (
+	"log"
 	"time"
 )
 
@@ -104,6 +105,25 @@ func (t Team) HasAccess(e Exercice) bool {
 	}
 }
 
+// CanDownload checks if the Team has access to the given file.
+func (t Team) CanDownload(f EFile) bool {
+	if deps, err := f.GetDepends(); err != nil {
+		log.Printf("Unable to retrieve file dependencies: %s\n", err)
+		return false
+	} else {
+		res := true
+
+		for _, dep := range deps {
+			if t.HasPartiallySolved(dep) == nil {
+				res = false
+				break
+			}
+		}
+
+		return res
+	}
+}
+
 // NbTry retrieves the number of attempts made by the Team to the given challenge.
 func NbTry(t *Team, e Exercice) int {
 	var cnt *int
diff --git a/libfic/team_my.go b/libfic/team_my.go
index 4fc61fcd..60264ada 100644
--- a/libfic/team_my.go
+++ b/libfic/team_my.go
@@ -115,7 +115,9 @@ func MyJSONTeam(t *Team, started bool) (interface{}, error) {
 					return nil, err
 				} else {
 					for _, f := range files {
-						exercice.Files = append(exercice.Files, myTeamFile{path.Join(FilesDir, f.Path), f.Name, hex.EncodeToString(f.Checksum), f.Size})
+						if t == nil || t.CanDownload(f) {
+							exercice.Files = append(exercice.Files, myTeamFile{path.Join(FilesDir, f.Path), f.Name, hex.EncodeToString(f.Checksum), f.Size})
+						}
 					}
 				}