diff --git a/plume-common/src/activity_pub/mod.rs b/plume-common/src/activity_pub/mod.rs
index c0ad233..5949c86 100644
--- a/plume-common/src/activity_pub/mod.rs
+++ b/plume-common/src/activity_pub/mod.rs
@@ -1,10 +1,8 @@
 use activitypub::{Activity, Actor, Object, Link};
 use array_tool::vec::Uniq;
-use base64;
 use reqwest::Client;
 use rocket::{
-    Outcome,
-    http::{Status,HeaderMap},
+    Outcome, http::Status,
     response::{Response, Responder},
     request::{FromRequest, Request}
 };
@@ -120,68 +118,6 @@ pub fn broadcast<S: sign::Signer, A: Activity, T: inbox::WithInbox + Actor>(send
     }
 }
 
-#[derive(Debug)]
-pub enum SignatureValidity {
-    Invalid,
-    ValidNoDigest,
-    Valid,
-    Absent,
-}
-
-impl SignatureValidity {
-    pub fn is_secure(&self) -> bool {
-        match self {
-            SignatureValidity::Valid => true,
-            _ => false,
-        }
-    }
-}
-
-pub fn verify_http_headers<S: sign::Signer+::std::fmt::Debug>(sender: &S, all_headers: HeaderMap, data: String) -> SignatureValidity{
-    if let Some(sig_header) = all_headers.get_one("Signature") {
-        let mut _key_id = None;
-        let mut _algorithm = None;
-        let mut headers = None;
-        let mut signature = None;
-        for part in sig_header.split(',') {
-            match part {
-                part if part.starts_with("keyId=") => _key_id = Some(&part[7..part.len()-1]),
-                part if part.starts_with("algorithm=") => _algorithm = Some(&part[11..part.len()-1]),
-                part if part.starts_with("headers=") => headers = Some(&part[9..part.len()-1]),
-                part if part.starts_with("signature=") => signature = Some(&part[11..part.len()-1]),
-                _ => {},
-            }
-        }
-        if signature.is_some() && headers.is_some() {
-            let headers = headers.unwrap().split_whitespace().collect::<Vec<_>>();
-            let signature = signature.unwrap();
-            let h = headers.iter()
-                .map(|header| (header,all_headers.get_one(header)))
-                .map(|(header, value)| format!("{}: {}", header.to_lowercase(), value.unwrap_or("")))
-                .collect::<Vec<_>>().join("\n");
-            if sender.verify(h, base64::decode(signature).unwrap_or(Vec::new())) {
-                if headers.contains(&"digest") {
-                    let digest = all_headers.get_one("digest").unwrap_or("");
-                    let digest = request::Digest::from_header(digest);
-                    if digest.map(|d| d.verify(data)).unwrap_or(false) {
-                        SignatureValidity::Valid
-                    } else {
-                        SignatureValidity::Invalid
-                    }
-                } else {
-                    SignatureValidity::ValidNoDigest
-                }
-            } else {
-                SignatureValidity::Invalid
-            }
-        } else {
-            SignatureValidity::Invalid
-        }
-    } else {
-        SignatureValidity::Absent
-    }
-}
-
 #[derive(Clone, Serialize, Deserialize)]
 pub struct Id(String);
 
diff --git a/plume-common/src/activity_pub/sign.rs b/plume-common/src/activity_pub/sign.rs
index 9d2f39c..fa9252e 100644
--- a/plume-common/src/activity_pub/sign.rs
+++ b/plume-common/src/activity_pub/sign.rs
@@ -6,6 +6,8 @@ use openssl::{
     rsa::Rsa,
     sha::sha256
 };
+use super::request;
+use rocket::http::HeaderMap;
 use serde_json;
 
 /// Returns (public key, private key)
@@ -26,6 +28,7 @@ pub trait Signer {
 
 pub trait Signable {
     fn sign<T>(&mut self, creator: &T) -> &mut Self where T: Signer;
+    fn verify<T>(self, creator: &T) -> bool where T: Signer;
 
     fn hash(data: String) -> String {
         let bytes = data.into_bytes();
@@ -55,4 +58,85 @@ impl Signable for serde_json::Value {
         self["signature"] = options;
         self
     }
+
+    fn verify<T: Signer>(mut self, creator: &T) -> bool {
+        let signature_obj = if let Some(sig) = self.as_object_mut().and_then(|o| o.remove("signature")) {
+            sig
+        } else {
+            //signature not present
+            return false
+        };
+        let signature = if let Ok(sig) = base64::decode(&signature_obj["signatureValue"].as_str().unwrap_or("")) {
+            sig
+        } else {
+            return false
+        };
+        let creation_date = &signature_obj["created"];
+        let options_hash  = Self::hash(json!({
+            "@context": "https://w3id.org/identity/v1",
+            "created": creation_date
+        }).to_string());
+        let document_hash = Self::hash(self.to_string());
+        let to_be_signed = options_hash + &document_hash;
+        creator.verify(to_be_signed, signature)
+    }
+}
+
+#[derive(Debug,Copy,Clone,PartialEq)]
+pub enum SignatureValidity {
+    Invalid,
+    ValidNoDigest,
+    Valid,
+    Absent,
+}
+
+impl SignatureValidity {
+    pub fn is_secure(&self) -> bool {
+        self==&SignatureValidity::Valid
+    }
+}
+
+pub fn verify_http_headers<S: Signer+::std::fmt::Debug>(sender: &S, all_headers: HeaderMap, data: String) -> SignatureValidity{
+    if let Some(sig_header) = all_headers.get_one("Signature") {
+        let mut _key_id = None;
+        let mut _algorithm = None;
+        let mut headers = None;
+        let mut signature = None;
+        for part in sig_header.split(',') {
+            match part {
+                part if part.starts_with("keyId=") => _key_id = Some(&part[7..part.len()-1]),
+                part if part.starts_with("algorithm=") => _algorithm = Some(&part[11..part.len()-1]),
+                part if part.starts_with("headers=") => headers = Some(&part[9..part.len()-1]),
+                part if part.starts_with("signature=") => signature = Some(&part[11..part.len()-1]),
+                _ => {},
+            }
+        }
+        if signature.is_some() && headers.is_some() {
+            let headers = headers.unwrap().split_whitespace().collect::<Vec<_>>();
+            let signature = signature.unwrap();
+            let h = headers.iter()
+                .map(|header| (header,all_headers.get_one(header)))
+                .map(|(header, value)| format!("{}: {}", header.to_lowercase(), value.unwrap_or("")))
+                .collect::<Vec<_>>().join("\n");
+            if sender.verify(h, base64::decode(signature).unwrap_or(Vec::new())) {
+                if headers.contains(&"digest") {
+                    let digest = all_headers.get_one("digest").unwrap_or("");
+                    let digest = request::Digest::from_header(digest);
+                    if digest.map(|d| d.verify(data)).unwrap_or(false) {
+                        SignatureValidity::Valid
+                    } else {
+                        SignatureValidity::Invalid
+                    }
+                } else {
+                    SignatureValidity::ValidNoDigest
+                }
+            } else {
+                SignatureValidity::Invalid
+            }
+        } else {
+            SignatureValidity::Invalid
+        }
+    } else {
+        SignatureValidity::Absent
+    }
 }
diff --git a/src/routes/instance.rs b/src/routes/instance.rs
index 8f592ed..901bf71 100644
--- a/src/routes/instance.rs
+++ b/src/routes/instance.rs
@@ -4,7 +4,8 @@ use rocket_contrib::{Json, Template};
 use serde_json;
 use validator::{Validate};
 
-use plume_common::activity_pub::verify_http_headers;
+use plume_common::activity_pub::sign::{Signable,
+    verify_http_headers};
 use plume_models::{
     admin::Admin,
     comments::Comment,
@@ -198,9 +199,9 @@ fn shared_inbox(conn: DbConn, data: String, headers: Headers) -> String {
     let actor_id = activity["actor"].as_str()
         .unwrap_or_else(|| activity["actor"]["id"].as_str().expect("No actor ID for incoming activity, blocks by panicking"));
 
-    let sig = verify_http_headers(&User::from_url(&conn, actor_id.to_owned()).unwrap(), headers.0, data).is_secure();
-    if !sig {
-        // TODO check for valid json-ld signature
+    let actor = User::from_url(&conn, actor_id.to_owned()).unwrap();
+    if !verify_http_headers(&actor, headers.0, data).is_secure() &&
+        !act.clone().verify(&actor) {
         return "invalid signature".to_owned();
     }
 
diff --git a/src/routes/user.rs b/src/routes/user.rs
index c206e51..8d655f3 100644
--- a/src/routes/user.rs
+++ b/src/routes/user.rs
@@ -16,7 +16,8 @@ use workerpool::thunk::*;
 
 use plume_common::activity_pub::{
     ActivityStream, broadcast, Id, IntoId, ApRequest,
-    verify_http_headers, inbox::{FromActivity, Notify, Deletable}
+    inbox::{FromActivity, Notify, Deletable},
+    sign::{Signable, verify_http_headers}
 };
 use plume_common::utils;
 use plume_models::{
@@ -304,9 +305,9 @@ fn inbox(name: String, conn: DbConn, data: String, headers: Headers) -> String {
     let actor_id = activity["actor"].as_str()
         .unwrap_or_else(|| activity["actor"]["id"].as_str().expect("User: No actor ID for incoming activity, blocks by panicking"));
 
-    let sig = verify_http_headers(&User::from_url(&conn, actor_id.to_owned()).unwrap(), headers.0, data).is_secure();
-    if !sig {
-        // TODO check for json-ld signature
+    let actor = User::from_url(&conn, actor_id.to_owned()).unwrap();
+    if !verify_http_headers(&actor, headers.0, data).is_secure() &&
+        !act.clone().verify(&actor) {
         return "invalid signature".to_owned();
     }