diff --git a/acme_common/Cargo.toml b/acme_common/Cargo.toml
index 2f15298..27c072c 100644
--- a/acme_common/Cargo.toml
+++ b/acme_common/Cargo.toml
@@ -13,7 +13,9 @@ publish = false
 name = "acme_common"
 
 [features]
+default = []
 openssl_dyn = ["openssl", "openssl-sys"]
+ed25519 = []
 
 [dependencies]
 attohttpc = { version = "0.15", default-features = false }
diff --git a/acme_common/src/crypto/jws_signature_algorithm.rs b/acme_common/src/crypto/jws_signature_algorithm.rs
index 8ccf57e..b2a9bcc 100644
--- a/acme_common/src/crypto/jws_signature_algorithm.rs
+++ b/acme_common/src/crypto/jws_signature_algorithm.rs
@@ -7,6 +7,7 @@ pub enum JwsSignatureAlgorithm {
     Rs256,
     Es256,
     Es384,
+    #[cfg(feature = "ed25519")]
     Ed25519,
 }
 
@@ -18,6 +19,7 @@ impl FromStr for JwsSignatureAlgorithm {
             "rs256" => Ok(JwsSignatureAlgorithm::Rs256),
             "es256" => Ok(JwsSignatureAlgorithm::Es256),
             "es384" => Ok(JwsSignatureAlgorithm::Es384),
+            #[cfg(feature = "ed25519")]
             "ed25519" => Ok(JwsSignatureAlgorithm::Ed25519),
             _ => Err(format!("{}: unknown algorithm.", s).into()),
         }
@@ -30,6 +32,7 @@ impl fmt::Display for JwsSignatureAlgorithm {
             JwsSignatureAlgorithm::Rs256 => "RS256",
             JwsSignatureAlgorithm::Es256 => "ES256",
             JwsSignatureAlgorithm::Es384 => "ES384",
+            #[cfg(feature = "ed25519")]
             JwsSignatureAlgorithm::Ed25519 => "Ed25519",
         };
         write!(f, "{}", s)
diff --git a/acme_common/src/crypto/key_type.rs b/acme_common/src/crypto/key_type.rs
index 3441cb8..84696ec 100644
--- a/acme_common/src/crypto/key_type.rs
+++ b/acme_common/src/crypto/key_type.rs
@@ -5,29 +5,31 @@ use std::str::FromStr;
 
 #[derive(Clone, Copy, Debug)]
 pub enum KeyType {
-    Curve25519,
-    EcdsaP256,
-    EcdsaP384,
     Rsa2048,
     Rsa4096,
+    EcdsaP256,
+    EcdsaP384,
+    #[cfg(feature = "ed25519")]
+    Ed25519,
 }
 
 impl KeyType {
     pub fn get_default_signature_alg(&self) -> JwsSignatureAlgorithm {
         match self {
-            KeyType::Curve25519 => JwsSignatureAlgorithm::Ed25519,
+            KeyType::Rsa2048 | KeyType::Rsa4096 => JwsSignatureAlgorithm::Rs256,
             KeyType::EcdsaP256 => JwsSignatureAlgorithm::Es256,
             KeyType::EcdsaP384 => JwsSignatureAlgorithm::Es384,
-            KeyType::Rsa2048 | KeyType::Rsa4096 => JwsSignatureAlgorithm::Rs256,
+            #[cfg(feature = "ed25519")]
+            KeyType::Ed25519 => JwsSignatureAlgorithm::Ed25519,
         }
     }
 
     pub fn check_alg_compatibility(&self, alg: &JwsSignatureAlgorithm) -> Result<(), Error> {
         let ok = match self {
-            KeyType::Curve25519 | KeyType::EcdsaP256 | KeyType::EcdsaP384 => {
-                *alg == self.get_default_signature_alg()
-            }
             KeyType::Rsa2048 | KeyType::Rsa4096 => *alg == JwsSignatureAlgorithm::Rs256,
+            KeyType::EcdsaP256 | KeyType::EcdsaP384 => *alg == self.get_default_signature_alg(),
+            #[cfg(feature = "ed25519")]
+            KeyType::Ed25519 => *alg == self.get_default_signature_alg(),
         };
         if ok {
             Ok(())
@@ -46,11 +48,12 @@ impl FromStr for KeyType {
 
     fn from_str(s: &str) -> Result<Self, Error> {
         match s.to_lowercase().as_str() {
-            "ed25519" => Ok(KeyType::Curve25519),
-            "ecdsa_p256" => Ok(KeyType::EcdsaP256),
-            "ecdsa_p384" => Ok(KeyType::EcdsaP384),
             "rsa2048" => Ok(KeyType::Rsa2048),
             "rsa4096" => Ok(KeyType::Rsa4096),
+            "ecdsa_p256" => Ok(KeyType::EcdsaP256),
+            "ecdsa_p384" => Ok(KeyType::EcdsaP384),
+            #[cfg(feature = "ed25519")]
+            "ed25519" => Ok(KeyType::Ed25519),
             _ => Err(format!("{}: unknown algorithm.", s).into()),
         }
     }
@@ -59,11 +62,12 @@ impl FromStr for KeyType {
 impl fmt::Display for KeyType {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let s = match self {
-            KeyType::Curve25519 => "ed25519",
-            KeyType::EcdsaP256 => "ecdsa-p256",
-            KeyType::EcdsaP384 => "ecdsa-p384",
             KeyType::Rsa2048 => "rsa2048",
             KeyType::Rsa4096 => "rsa4096",
+            KeyType::EcdsaP256 => "ecdsa-p256",
+            KeyType::EcdsaP384 => "ecdsa-p384",
+            #[cfg(feature = "ed25519")]
+            KeyType::Ed25519 => "ed25519",
         };
         write!(f, "{}", s)
     }
diff --git a/acme_common/src/crypto/openssl_keys.rs b/acme_common/src/crypto/openssl_keys.rs
index 73172c2..ab491a3 100644
--- a/acme_common/src/crypto/openssl_keys.rs
+++ b/acme_common/src/crypto/openssl_keys.rs
@@ -70,9 +70,6 @@ impl KeyPair {
             JwsSignatureAlgorithm::Rs256 => self.sign_rsa(&MessageDigest::sha256(), data),
             JwsSignatureAlgorithm::Es256 => self.sign_ecdsa(&crate::crypto::sha256, data),
             JwsSignatureAlgorithm::Es384 => self.sign_ecdsa(&crate::crypto::sha384, data),
-            JwsSignatureAlgorithm::Ed25519 => {
-                Err("Curve25519 signatures are not implemented yet".into())
-            }
         }
     }
 
@@ -107,7 +104,6 @@ impl KeyPair {
 
     fn get_jwk_public_key(&self, thumbprint: bool) -> Result<Value, Error> {
         match self.key_type {
-            KeyType::Curve25519 => Err("Curve25519 thumbprint are not implemented yet".into()),
             KeyType::EcdsaP256 | KeyType::EcdsaP384 => self.get_nist_ec_jwk(thumbprint),
             KeyType::Rsa2048 | KeyType::Rsa4096 => self.get_rsa_jwk(thumbprint),
         }
@@ -198,7 +194,6 @@ fn gen_ec_pair(nid: Nid) -> Result<PKey<Private>, Error> {
 
 pub fn gen_keypair(key_type: KeyType) -> Result<KeyPair, Error> {
     let priv_key = match key_type {
-        KeyType::Curve25519 => Err(Error::from("")),
         KeyType::EcdsaP256 => gen_ec_pair(Nid::X9_62_PRIME256V1),
         KeyType::EcdsaP384 => gen_ec_pair(Nid::SECP384R1),
         KeyType::Rsa2048 => gen_rsa_pair(2048),