diff --git a/CHANGELOG.md b/CHANGELOG.md
index b8153bc..d599f2d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Changed
 
 - Use proof suites with prefix `Mitra`.
+- Add `https://w3id.org/security/data-integrity/v1` to JSON-LD context.
 
 ## [1.12.0] - 2023-01-26
 
diff --git a/FEDERATION.md b/FEDERATION.md
index fbd10c2..02b57a8 100644
--- a/FEDERATION.md
+++ b/FEDERATION.md
@@ -43,7 +43,10 @@ Example:
 
 ```json
 {
-  "@context": "https://www.w3.org/ns/activitystreams",
+  "@context": [
+    "https://www.w3.org/ns/activitystreams",
+    "https://w3id.org/security/data-integrity/v1"
+  ],
   "actor": "https://example.com/users/alice",
   "cc": [],
   "id": "https://example.com/objects/0185f5f8-10b5-1b69-f45e-25f06792f411",
diff --git a/src/activitypub/actors/types.rs b/src/activitypub/actors/types.rs
index 9fe70db..194b125 100644
--- a/src/activitypub/actors/types.rs
+++ b/src/activitypub/actors/types.rs
@@ -7,7 +7,11 @@ use serde::{
 use serde_json::{json, Value};
 
 use crate::activitypub::{
-    constants::{ACTOR_KEY_SUFFIX, AP_CONTEXT},
+    constants::{
+        ACTOR_KEY_SUFFIX,
+        AP_CONTEXT,
+        W3ID_SECURITY_CONTEXT,
+    },
     identifiers::{local_actor_id, LocalActorCollection},
     receiver::parse_property_value,
     vocabulary::{IDENTITY_PROOF, IMAGE, LINK, PERSON, PROPERTY_VALUE, SERVICE},
@@ -33,8 +37,6 @@ use super::attachments::{
     parse_payment_option,
 };
 
-const W3ID_CONTEXT: &str = "https://w3id.org/security/v1";
-
 #[derive(Clone, Debug, Deserialize, Serialize)]
 #[cfg_attr(test, derive(Default))]
 #[serde(rename_all = "camelCase")]
@@ -300,7 +302,7 @@ pub fn get_local_actor(
     let actor = Actor {
         context: Some(json!([
             AP_CONTEXT.to_string(),
-            W3ID_CONTEXT.to_string(),
+            W3ID_SECURITY_CONTEXT.to_string(),
         ])),
         id: actor_id.clone(),
         object_type: PERSON.to_string(),
@@ -339,7 +341,7 @@ pub fn get_instance_actor(
     let actor = Actor {
         context: Some(json!([
             AP_CONTEXT.to_string(),
-            W3ID_CONTEXT.to_string(),
+            W3ID_SECURITY_CONTEXT.to_string(),
         ])),
         id: actor_id,
         object_type: SERVICE.to_string(),
diff --git a/src/activitypub/builders/accept_follow.rs b/src/activitypub/builders/accept_follow.rs
index 68d5d01..fff87f0 100644
--- a/src/activitypub/builders/accept_follow.rs
+++ b/src/activitypub/builders/accept_follow.rs
@@ -2,9 +2,9 @@ use serde::Serialize;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::ACCEPT,
 };
 use crate::config::Instance;
@@ -15,7 +15,7 @@ use crate::utils::id::new_uuid;
 #[derive(Serialize)]
 struct AcceptFollow {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -37,7 +37,7 @@ fn build_accept_follow(
     let activity_id = local_object_id(instance_url, &new_uuid());
     let actor_id = local_actor_id(instance_url, &actor_profile.username);
     AcceptFollow {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: ACCEPT.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/add_person.rs b/src/activitypub/builders/add_person.rs
index 8bfef5a..b58e355 100644
--- a/src/activitypub/builders/add_person.rs
+++ b/src/activitypub/builders/add_person.rs
@@ -2,9 +2,9 @@ use serde::Serialize;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id, LocalActorCollection},
+    types::{build_default_context, Context},
     vocabulary::{ADD, REMOVE},
 };
 use crate::config::Instance;
@@ -14,7 +14,7 @@ use crate::utils::id::new_uuid;
 #[derive(Serialize)]
 struct AddOrRemovePerson {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -39,7 +39,7 @@ fn build_update_collection(
     let activity_type = if remove { REMOVE } else { ADD };
     let collection_id = collection.of(&actor_id);
     AddOrRemovePerson {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         id: activity_id,
         activity_type: activity_type.to_string(),
         actor: actor_id,
diff --git a/src/activitypub/builders/announce.rs b/src/activitypub/builders/announce.rs
index 83ffec1..823cadf 100644
--- a/src/activitypub/builders/announce.rs
+++ b/src/activitypub/builders/announce.rs
@@ -3,9 +3,10 @@ use serde::Serialize;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::{AP_CONTEXT, AP_PUBLIC},
+    constants::AP_PUBLIC,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_followers, local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::ANNOUNCE,
 };
 use crate::config::Instance;
@@ -17,7 +18,7 @@ use crate::models::users::types::User;
 #[derive(Serialize)]
 struct Announce {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -43,7 +44,7 @@ fn build_announce(
     let recipient_id = post.author.actor_id(instance_url);
     let followers = local_actor_followers(instance_url, sender_username);
     Announce {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: ANNOUNCE.to_string(),
         actor: actor_id,
         id: activity_id,
diff --git a/src/activitypub/builders/create_note.rs b/src/activitypub/builders/create_note.rs
index 93041e3..bb4c906 100644
--- a/src/activitypub/builders/create_note.rs
+++ b/src/activitypub/builders/create_note.rs
@@ -3,7 +3,7 @@ use serde::Serialize;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::{AP_MEDIA_TYPE, AP_CONTEXT, AP_PUBLIC},
+    constants::{AP_MEDIA_TYPE, AP_PUBLIC},
     deliverer::OutgoingActivity,
     identifiers::{
         local_actor_id,
@@ -13,7 +13,15 @@ use crate::activitypub::{
         local_object_id,
         local_tag_collection,
     },
-    types::{Attachment, EmojiTag, EmojiTagImage, LinkTag, SimpleTag},
+    types::{
+        build_default_context,
+        Attachment,
+        Context,
+        EmojiTag,
+        EmojiTagImage,
+        LinkTag,
+        SimpleTag,
+    },
     vocabulary::*,
 };
 use crate::config::Instance;
@@ -40,7 +48,7 @@ enum Tag {
 #[serde(rename_all = "camelCase")]
 pub struct Note {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     id: String,
 
@@ -180,7 +188,7 @@ pub fn build_note(
         None => None,
     };
     Note {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         id: object_id,
         object_type: NOTE.to_string(),
         attachment: attachments,
@@ -198,7 +206,7 @@ pub fn build_note(
 #[derive(Serialize)]
 pub struct CreateNote {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -221,7 +229,7 @@ pub fn build_create_note(
     let secondary_audience = object.cc.clone();
     let activity_id = format!("{}/create", object.id);
     CreateNote {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: CREATE.to_string(),
         id: activity_id,
         actor: object.attributed_to.clone(),
diff --git a/src/activitypub/builders/delete_note.rs b/src/activitypub/builders/delete_note.rs
index 8500c13..8f11ecb 100644
--- a/src/activitypub/builders/delete_note.rs
+++ b/src/activitypub/builders/delete_note.rs
@@ -1,9 +1,9 @@
 use serde::Serialize;
 
 use crate::activitypub::{
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::local_actor_id,
+    types::{build_default_context, Context},
     vocabulary::{DELETE, NOTE, TOMBSTONE},
 };
 use crate::config::Instance;
@@ -31,7 +31,7 @@ struct Tombstone {
 #[derive(Serialize)]
 struct DeleteNote {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -58,7 +58,7 @@ fn build_delete_note(
         post,
     );
     DeleteNote {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: DELETE.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/delete_person.rs b/src/activitypub/builders/delete_person.rs
index a2f7b40..ef85d98 100644
--- a/src/activitypub/builders/delete_person.rs
+++ b/src/activitypub/builders/delete_person.rs
@@ -3,8 +3,9 @@ use uuid::Uuid;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::{AP_CONTEXT, AP_PUBLIC},
+    constants::AP_PUBLIC,
     deliverer::OutgoingActivity,
+    types::{build_default_context, Context},
     vocabulary::DELETE,
 };
 use crate::config::Instance;
@@ -15,7 +16,7 @@ use crate::models::users::types::User;
 #[derive(Serialize)]
 struct DeletePerson {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -34,7 +35,7 @@ fn build_delete_person(
     let actor_id = user.profile.actor_id(instance_url);
     let activity_id = format!("{}/delete", actor_id);
     DeletePerson {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: DELETE.to_string(),
         id: activity_id,
         actor: actor_id.clone(),
diff --git a/src/activitypub/builders/follow.rs b/src/activitypub/builders/follow.rs
index e91816d..d7d7a62 100644
--- a/src/activitypub/builders/follow.rs
+++ b/src/activitypub/builders/follow.rs
@@ -3,9 +3,9 @@ use uuid::Uuid;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::FOLLOW,
 };
 use crate::config::Instance;
@@ -15,7 +15,7 @@ use crate::models::users::types::User;
 #[derive(Serialize)]
 pub(super) struct Follow {
     #[serde(rename = "@context")]
-    pub context: String,
+    pub context: Context,
 
     #[serde(rename = "type")]
     pub activity_type: String,
@@ -36,7 +36,7 @@ fn build_follow(
     let activity_id = local_object_id(instance_url, follow_request_id);
     let actor_id = local_actor_id(instance_url, &actor_profile.username);
     Follow {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: FOLLOW.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/like.rs b/src/activitypub/builders/like.rs
index cd1f179..32bac4a 100644
--- a/src/activitypub/builders/like.rs
+++ b/src/activitypub/builders/like.rs
@@ -3,9 +3,10 @@ use uuid::Uuid;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::{AP_CONTEXT, AP_PUBLIC},
+    constants::AP_PUBLIC,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::LIKE,
 };
 use crate::config::Instance;
@@ -17,7 +18,7 @@ use crate::models::users::types::User;
 #[derive(Serialize)]
 struct Like {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -55,7 +56,7 @@ fn build_like(
     let (primary_audience, secondary_audience) =
         get_like_audience(post_author_id, post_visibility);
     Like {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: LIKE.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/move_person.rs b/src/activitypub/builders/move_person.rs
index 60f6939..da1589f 100644
--- a/src/activitypub/builders/move_person.rs
+++ b/src/activitypub/builders/move_person.rs
@@ -3,9 +3,9 @@ use uuid::Uuid;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::MOVE,
 };
 use crate::config::Instance;
@@ -15,7 +15,7 @@ use crate::utils::id::new_uuid;
 #[derive(Serialize)]
 pub struct MovePerson {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -40,7 +40,7 @@ pub fn build_move_person(
     let activity_id = local_object_id(instance_url, &internal_activity_id);
     let actor_id = local_actor_id(instance_url, &sender.profile.username);
     MovePerson {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: MOVE.to_string(),
         id: activity_id,
         actor: actor_id.clone(),
diff --git a/src/activitypub/builders/undo_announce.rs b/src/activitypub/builders/undo_announce.rs
index 0de1963..be60b40 100644
--- a/src/activitypub/builders/undo_announce.rs
+++ b/src/activitypub/builders/undo_announce.rs
@@ -2,9 +2,10 @@ use serde::Serialize;
 use uuid::Uuid;
 
 use crate::activitypub::{
-    constants::{AP_CONTEXT, AP_PUBLIC},
+    constants::AP_PUBLIC,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_actor_followers, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::UNDO,
 };
 use crate::config::Instance;
@@ -17,7 +18,7 @@ use super::announce::get_announce_recipients;
 #[derive(Serialize)]
 struct UndoAnnounce {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -47,7 +48,7 @@ fn build_undo_announce(
         local_actor_followers(instance_url, &actor_profile.username),
     ];
     UndoAnnounce {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: UNDO.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/undo_follow.rs b/src/activitypub/builders/undo_follow.rs
index a743555..d29946a 100644
--- a/src/activitypub/builders/undo_follow.rs
+++ b/src/activitypub/builders/undo_follow.rs
@@ -3,9 +3,9 @@ use uuid::Uuid;
 
 use crate::activitypub::{
     actors::types::Actor,
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::{FOLLOW, UNDO},
 };
 use crate::config::Instance;
@@ -16,7 +16,7 @@ use super::follow::Follow;
 #[derive(Serialize)]
 struct UndoFollow {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -43,7 +43,7 @@ fn build_undo_follow(
         &actor_profile.username,
     );
     let object = Follow {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: FOLLOW.to_string(),
         id: follow_activity_id,
         actor: follow_actor_id,
@@ -53,7 +53,7 @@ fn build_undo_follow(
     let activity_id = format!("{}/undo", object.id);
     let actor_id = local_actor_id(instance_url, &actor_profile.username);
     UndoFollow {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: UNDO.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/undo_like.rs b/src/activitypub/builders/undo_like.rs
index 8dca1fa..1898ad0 100644
--- a/src/activitypub/builders/undo_like.rs
+++ b/src/activitypub/builders/undo_like.rs
@@ -2,9 +2,9 @@ use serde::Serialize;
 use uuid::Uuid;
 
 use crate::activitypub::{
-    constants::AP_CONTEXT,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_id, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::UNDO,
 };
 use crate::config::Instance;
@@ -20,7 +20,7 @@ use super::like::{
 #[derive(Serialize)]
 struct UndoLike {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -46,7 +46,7 @@ fn build_undo_like(
     let (primary_audience, secondary_audience) =
         get_like_audience(post_author_id, post_visibility);
     UndoLike {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: UNDO.to_string(),
         id: activity_id,
         actor: actor_id,
diff --git a/src/activitypub/builders/update_person.rs b/src/activitypub/builders/update_person.rs
index e9b4ac3..0658514 100644
--- a/src/activitypub/builders/update_person.rs
+++ b/src/activitypub/builders/update_person.rs
@@ -3,9 +3,10 @@ use uuid::Uuid;
 
 use crate::activitypub::{
     actors::types::{get_local_actor, Actor, ActorKeyError},
-    constants::{AP_CONTEXT, AP_PUBLIC},
+    constants::AP_PUBLIC,
     deliverer::OutgoingActivity,
     identifiers::{local_actor_followers, local_object_id},
+    types::{build_default_context, Context},
     vocabulary::UPDATE,
 };
 use crate::config::Instance;
@@ -17,7 +18,7 @@ use crate::utils::id::new_uuid;
 #[derive(Serialize)]
 pub struct UpdatePerson {
     #[serde(rename = "@context")]
-    context: String,
+    context: Context,
 
     #[serde(rename = "type")]
     activity_type: String,
@@ -40,7 +41,7 @@ pub fn build_update_person(
         maybe_internal_activity_id.unwrap_or(new_uuid());
     let activity_id = local_object_id(instance_url, &internal_activity_id);
     let activity = UpdatePerson {
-        context: AP_CONTEXT.to_string(),
+        context: build_default_context(),
         activity_type: UPDATE.to_string(),
         id: activity_id,
         actor: actor.id.clone(),
diff --git a/src/activitypub/collections.rs b/src/activitypub/collections.rs
index 67a5999..e3cc02a 100644
--- a/src/activitypub/collections.rs
+++ b/src/activitypub/collections.rs
@@ -1,14 +1,14 @@
 use serde::Serialize;
 use serde_json::{json, Value};
 
-use super::constants::AP_CONTEXT;
+use super::types::{build_default_context, Context};
 use super::vocabulary::{ORDERED_COLLECTION, ORDERED_COLLECTION_PAGE};
 
 #[derive(Serialize)]
 #[serde(rename_all = "camelCase")]
 pub struct OrderedCollection {
     #[serde(rename = "@context")]
-    pub context: Value,
+    pub context: Context,
 
     pub id: String,
 
@@ -29,7 +29,7 @@ impl OrderedCollection {
         total_items: Option<i32>,
     ) -> Self {
         Self {
-            context: json!(AP_CONTEXT),
+            context: build_default_context(),
             id: collection_id,
             object_type: ORDERED_COLLECTION.to_string(),
             first: first_page_id,
@@ -44,7 +44,7 @@ pub const COLLECTION_PAGE_SIZE: u16 = 10;
 #[serde(rename_all = "camelCase")]
 pub struct OrderedCollectionPage {
     #[serde(rename = "@context")]
-    pub context: Value,
+    pub context: Context,
 
     pub id: String,
 
@@ -62,7 +62,7 @@ impl OrderedCollectionPage {
         let ordered_items = items.into_iter()
             .map(|item| json!(item)).collect();
         Self {
-            context: json!(AP_CONTEXT),
+            context: build_default_context(),
             id: collection_page_id,
             object_type: ORDERED_COLLECTION_PAGE.to_string(),
             ordered_items,
diff --git a/src/activitypub/constants.rs b/src/activitypub/constants.rs
index 05c7bc8..4f09ead 100644
--- a/src/activitypub/constants.rs
+++ b/src/activitypub/constants.rs
@@ -2,7 +2,10 @@
 pub const AP_MEDIA_TYPE: &str = r#"application/ld+json; profile="https://www.w3.org/ns/activitystreams""#;
 pub const AS_MEDIA_TYPE: &str = "application/activity+json";
 
+// Contexts
 pub const AP_CONTEXT: &str = "https://www.w3.org/ns/activitystreams";
 pub const AP_PUBLIC: &str = "https://www.w3.org/ns/activitystreams#Public";
+pub const W3ID_SECURITY_CONTEXT: &str = "https://w3id.org/security/v1";
+pub const W3ID_DATA_INTEGRITY_CONTEXT: &str = "https://w3id.org/security/data-integrity/v1";
 
 pub const ACTOR_KEY_SUFFIX: &str = "#main-key";
diff --git a/src/activitypub/types.rs b/src/activitypub/types.rs
index d0786a0..d3bd8b5 100644
--- a/src/activitypub/types.rs
+++ b/src/activitypub/types.rs
@@ -2,6 +2,7 @@ use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
+use super::constants::{AP_CONTEXT, W3ID_DATA_INTEGRITY_CONTEXT};
 use super::vocabulary::HASHTAG;
 
 #[derive(Deserialize, Serialize)]
@@ -99,3 +100,12 @@ pub struct Object {
     pub updated: Option<DateTime<Utc>>,
     pub url: Option<Value>,
 }
+
+pub type Context = [&'static str; 2];
+
+pub const fn build_default_context() -> Context {
+    [
+        AP_CONTEXT,
+        W3ID_DATA_INTEGRITY_CONTEXT,
+    ]
+}