diff --git a/proto/observation/v5.proto b/proto/observation/v5.proto
index dd807e29..fe154b83 100644
--- a/proto/observation/v5.proto
+++ b/proto/observation/v5.proto
@@ -32,6 +32,7 @@ message Observation_5 {
     bytes driveId = 1;
     string name = 2;
     AttachmentType type = 3;
+    bytes hash = 4;
   }
   repeated Attachment attachments = 8;
 
diff --git a/schema/observation/v5.json b/schema/observation/v5.json
index 912e7f40..318860a6 100644
--- a/schema/observation/v5.json
+++ b/schema/observation/v5.json
@@ -100,9 +100,13 @@
               "UNRECOGNIZED": "future attachment type"
             },
             "enum": ["photo", "video", "audio", "UNRECOGNIZED"]
+          },
+          "hash": {
+            "type": "string",
+            "description": "SHA256 hash of the attachment"
           }
         },
-        "required": ["driveId", "name", "type"]
+        "required": ["driveId", "name", "type", "hash"]
       }
     },
     "tags": {
diff --git a/src/lib/decode-conversions.ts b/src/lib/decode-conversions.ts
index 9bd50e65..81fb63aa 100644
--- a/src/lib/decode-conversions.ts
+++ b/src/lib/decode-conversions.ts
@@ -55,8 +55,8 @@ export const convertObservation: ConvertFunction<'observation'> = (
     ...jsonSchemaCommon,
     ...rest,
     refs: message.refs?.map(({ id }) => ({ id: id.toString('hex') })),
-    attachments: message.attachments?.map(({ driveId, name, type }) => {
-      return { driveId: driveId.toString('hex'), name, type }
+    attachments: message.attachments?.map(({ driveId, name, type, hash }) => {
+      return { driveId: driveId.toString('hex'), name, type, hash: hash.toString('hex') }
     }),
     tags: convertTags(message.tags),
     metadata: message.metadata || {},
diff --git a/src/lib/encode-converstions.ts b/src/lib/encode-converstions.ts
index 15f85ad2..c95fc58a 100644
--- a/src/lib/encode-converstions.ts
+++ b/src/lib/encode-converstions.ts
@@ -83,6 +83,7 @@ export const convertObservation: ConvertFunction<'observation'> = (
       driveId: Buffer.from(attachment.driveId, 'hex'),
       name: attachment.name,
       type: attachment.type,
+      hash: Buffer.from(attachment.hash, 'hex'),
     }
   })
 
diff --git a/test/fixtures/cached.js b/test/fixtures/cached.js
index 58c5b950..63a4363d 100644
--- a/test/fixtures/cached.js
+++ b/test/fixtures/cached.js
@@ -10,7 +10,10 @@ export const cachedValues = {
   coreId: randomBytes(32).toString('hex'),
   createdAt: date,
   updatedAt: date,
-  attachments: { driveId: randomBytes(32).toString('hex') },
+  attachments: {
+    driveId: randomBytes(32).toString('hex'),
+    hash: randomBytes(32).toString('hex'),
+  },
   metadata: {
     position: {
       timestamp: date,
diff --git a/test/fixtures/good-docs-completed.js b/test/fixtures/good-docs-completed.js
index f48f1116..f0927a2c 100644
--- a/test/fixtures/good-docs-completed.js
+++ b/test/fixtures/good-docs-completed.js
@@ -25,6 +25,7 @@ export const goodDocsCompleted = [
           name: 'myFile',
           type: 'photo',
           driveId: cachedValues.attachments.driveId,
+          hash: cachedValues.attachments.hash,
         },
       ],
       tags: {