diff --git a/Cargo.toml b/Cargo.toml
index 1a739ac..9ad50d5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -14,11 +14,11 @@ rand = "0.8.4"
 uuid = { version = "0.8.2", features = ["serde"] }
 # Authentification
 jwt = "0.15.0"
-hmac = "*"
-sha2 = "*"
+hmac = "0.11.0"
+sha2 = { version = "0.9.0", default_features = false }
 # Timestamps for JWT tokens
-chrono = { version = "*", features = [ "serde" ] }
+chrono = { version = "0.4.19", features = [ "serde" ] }
 # Encoding of refresh tokens
 base64 = "0.13.0"
 # Reading in configuration files
-figment = { version = "*", features = [ "yaml" ] }
+figment = { version = "0.10.6", features = [ "yaml" ] }