diff --git a/plume-common/src/activity_pub/sign.rs b/plume-common/src/activity_pub/sign.rs
index c97cb5dd..22aaf9d6 100644
--- a/plume-common/src/activity_pub/sign.rs
+++ b/plume-common/src/activity_pub/sign.rs
@@ -19,20 +19,25 @@ pub fn gen_keypair() -> (Vec<u8>, Vec<u8>) {
 
 #[derive(Debug)]
 pub struct Error();
+pub type Result<T> = std::result::Result<T, Error>;
+
+impl From<openssl::error::ErrorStack> for Error {
+    fn from(_: openssl::error::ErrorStack) -> Self {
+        Self()
+    }
+}
 
 pub trait Signer {
-    type Error;
-
     fn get_key_id(&self) -> String;
 
     /// Sign some data with the signer keypair
-    fn sign(&self, to_sign: &str) -> Result<Vec<u8>, Self::Error>;
+    fn sign(&self, to_sign: &str) -> Result<Vec<u8>>;
     /// Verify if the signature is valid
-    fn verify(&self, data: &str, signature: &[u8]) -> Result<bool, Self::Error>;
+    fn verify(&self, data: &str, signature: &[u8]) -> Result<bool>;
 }
 
 pub trait Signable {
-    fn sign<T>(&mut self, creator: &T) -> Result<&mut Self, Error>
+    fn sign<T>(&mut self, creator: &T) -> Result<&mut Self>
     where
         T: Signer;
     fn verify<T>(self, creator: &T) -> bool
@@ -46,7 +51,7 @@ pub trait Signable {
 }
 
 impl Signable for serde_json::Value {
-    fn sign<T: Signer>(&mut self, creator: &T) -> Result<&mut serde_json::Value, Error> {
+    fn sign<T: Signer>(&mut self, creator: &T) -> Result<&mut serde_json::Value> {
         let creation_date = Utc::now().to_rfc3339();
         let mut options = json!({
             "type": "RsaSignature2017",
diff --git a/plume-models/src/blogs.rs b/plume-models/src/blogs.rs
index 4043c85e..da556225 100644
--- a/plume-models/src/blogs.rs
+++ b/plume-models/src/blogs.rs
@@ -462,24 +462,22 @@ impl AsActor<&PlumeRocket> for Blog {
 }
 
 impl sign::Signer for Blog {
-    type Error = Error;
-
     fn get_key_id(&self) -> String {
         format!("{}#main-key", self.ap_url)
     }
 
-    fn sign(&self, to_sign: &str) -> Result<Vec<u8>> {
-        let key = self.get_keypair()?;
+    fn sign(&self, to_sign: &str) -> sign::Result<Vec<u8>> {
+        let key = self.get_keypair().map_err(|_| sign::Error())?;
         let mut signer = Signer::new(MessageDigest::sha256(), &key)?;
         signer.update(to_sign.as_bytes())?;
-        signer.sign_to_vec().map_err(Error::from)
+        signer.sign_to_vec().map_err(sign::Error::from)
     }
 
-    fn verify(&self, data: &str, signature: &[u8]) -> Result<bool> {
+    fn verify(&self, data: &str, signature: &[u8]) -> sign::Result<bool> {
         let key = PKey::from_rsa(Rsa::public_key_from_pem(self.public_key.as_ref())?)?;
         let mut verifier = Verifier::new(MessageDigest::sha256(), &key)?;
         verifier.update(data.as_bytes())?;
-        verifier.verify(signature).map_err(Error::from)
+        verifier.verify(signature).map_err(sign::Error::from)
     }
 }
 
diff --git a/plume-models/src/lib.rs b/plume-models/src/lib.rs
index bd1474ec..33a5ec2b 100755
--- a/plume-models/src/lib.rs
+++ b/plume-models/src/lib.rs
@@ -17,7 +17,7 @@ extern crate serde_json;
 extern crate tantivy;
 
 use once_cell::sync::Lazy;
-use plume_common::activity_pub::inbox::InboxError;
+use plume_common::activity_pub::{inbox::InboxError, sign};
 use posts::PostEvent;
 use riker::actors::{channel, ActorSystem, ChannelRef, SystemBuilder};
 use users::UserEvent;
@@ -79,6 +79,12 @@ impl From<openssl::error::ErrorStack> for Error {
     }
 }
 
+impl From<sign::Error> for Error {
+    fn from(_: sign::Error) -> Self {
+        Error::Signature
+    }
+}
+
 impl From<diesel::result::Error> for Error {
     fn from(err: diesel::result::Error) -> Self {
         Error::Db(err)
diff --git a/plume-models/src/users.rs b/plume-models/src/users.rs
index d0325afd..04e27d5f 100644
--- a/plume-models/src/users.rs
+++ b/plume-models/src/users.rs
@@ -24,7 +24,7 @@ use plume_common::{
     activity_pub::{
         ap_accept_header,
         inbox::{AsActor, AsObject, FromId},
-        sign::{gen_keypair, Signer},
+        sign::{gen_keypair, Error as SignError, Result as SignResult, Signer},
         ActivityStream, ApSignature, Id, IntoId, PublicKey, PUBLIC_VISIBILITY,
     },
     utils,
@@ -1071,24 +1071,22 @@ impl AsObject<User, Delete, &DbConn> for User {
 }
 
 impl Signer for User {
-    type Error = Error;
-
     fn get_key_id(&self) -> String {
         format!("{}#main-key", self.ap_url)
     }
 
-    fn sign(&self, to_sign: &str) -> Result<Vec<u8>> {
-        let key = self.get_keypair()?;
+    fn sign(&self, to_sign: &str) -> SignResult<Vec<u8>> {
+        let key = self.get_keypair().map_err(|_| SignError())?;
         let mut signer = sign::Signer::new(MessageDigest::sha256(), &key)?;
         signer.update(to_sign.as_bytes())?;
-        signer.sign_to_vec().map_err(Error::from)
+        signer.sign_to_vec().map_err(SignError::from)
     }
 
-    fn verify(&self, data: &str, signature: &[u8]) -> Result<bool> {
+    fn verify(&self, data: &str, signature: &[u8]) -> SignResult<bool> {
         let key = PKey::from_rsa(Rsa::public_key_from_pem(self.public_key.as_ref())?)?;
         let mut verifier = sign::Verifier::new(MessageDigest::sha256(), &key)?;
         verifier.update(data.as_bytes())?;
-        verifier.verify(signature).map_err(Error::from)
+        verifier.verify(signature).map_err(SignError::from)
     }
 }