diff --git a/src/aquarius/Aquarius.ts b/src/aquarius/Aquarius.ts
index cd52a2f..8a757d2 100644
--- a/src/aquarius/Aquarius.ts
+++ b/src/aquarius/Aquarius.ts
@@ -3,6 +3,7 @@ import { DDO } from '../ddo/DDO'
 import DID from '../ocean/DID'
 import { Logger } from '../utils'
 import { WebServiceConnector } from '../ocean/utils/WebServiceConnector'
+import { Account } from '../squid'
 
 const apiPath = '/api/v1/aquarius/assets/ddo'
 
@@ -215,6 +216,74 @@ export class Aquarius {
         return this.retrieveDDO(undefined, metadataServiceEndpoint)
     }
 
+    /**
+     * Updates a DDO.
+     * @param  {DID | string} did DID of the asset to update.
+     * @param  {DDO} newDdo New DDO of the asset.
+     * @return {Promise<DDO>} Updated DDO of the asset.
+     */
+    public async updateDDO(did: DID | string, newDdo: DDO): Promise<DDO> {
+        did = did && DID.parse(did)
+        const fullUrl = `${this.url}${apiPath}/${did.getDid()}`
+        const result = await this.fetch
+            .put(fullUrl, DDO.serialize(newDdo))
+            .then((response: any) => {
+                if (response.ok) {
+                    return response.json()
+                }
+                this.logger.log(
+                    'updateDDO failed:',
+                    response.status,
+                    response.statusText,
+                    did
+                )
+                return null as DDO
+            })
+            .then((response: DDO) => {
+                return new DDO(response) as DDO
+            })
+            .catch(error => {
+                this.logger.error('Error updating metadata: ', error)
+                return null as DDO
+            })
+
+        return result
+    }
+
+    
+    /**
+     * Transfer ownership of a DDO
+     * @param  {DID | string} did DID of the asset to update.
+     * @param  {String} newOwner New owner of the DDO
+     * @param  {String} updated Updated field of the DDO
+     * @param  {String} signature Signature using updated field to verify that the consumer has rights
+     * @return {Promise<String>} Result.
+     */
+    public async transferOwnership(did: DID | string, newOwner: string, updated: string, signature: string): Promise<String> {
+        did = did && DID.parse(did)
+        const fullUrl = `${this.url}${apiPath}/transferownership/${did.getDid()}`
+        const result = await this.fetch
+            .put(fullUrl, JSON.stringify({signature: signature, updated: updated, newowner: newOwner}))
+            .then((response: any) => {
+                if (response.ok) {
+                    return response.text
+                }
+                this.logger.log(
+                    'transferownership failed:',
+                    response.status,
+                    response.statusText
+                )
+                return null 
+            })
+            
+            .catch(error => {
+                this.logger.error('Error updating metadata: ', error)
+                return null
+            })
+
+        return result
+    }
+
     public getServiceEndpoint(did: DID) {
         return `${this.url}/api/v1/aquarius/assets/ddo/did:op:${did.getId()}`
     }
diff --git a/src/ddo/DDO.ts b/src/ddo/DDO.ts
index 4692294..8f56cb7 100644
--- a/src/ddo/DDO.ts
+++ b/src/ddo/DDO.ts
@@ -40,6 +40,8 @@ export class DDO {
 
     public created: string
 
+    public updated: string
+
     public publicKey: PublicKey[] = []
 
     public authentication: Authentication[] = []
diff --git a/src/ocean/OceanAssets.ts b/src/ocean/OceanAssets.ts
index 537fd8b..7a25689 100644
--- a/src/ocean/OceanAssets.ts
+++ b/src/ocean/OceanAssets.ts
@@ -412,14 +412,29 @@ export class OceanAssets extends Instantiable {
      * Transfer ownership of an asset.
      * @param  {string} did Asset DID.
      * @param  {string} newOwner Ethereum address of the new owner of the DID.
+     * @param  {Account} account Ethereum account to sign and prove the ownership.
      * @return {Promise<TransactionReceipt>} Returns Web3 transaction receipt.
      */
     public async transferOwnership(
         did: string,
-        newOwner: string
+        newOwner: string,
+        account: Account
     ): Promise<TransactionReceipt> {
-        const owner = await this.ocean.assets.owner(did)
-        return this.ocean.keeper.didRegistry.transferDIDOwnership(did, newOwner, owner)
+        const oldOwner = await this.ocean.assets.owner(did)
+        const oldDdo = await this.ocean.aquarius.retrieveDDO(did)
+
+        // update owner on-chain
+        const txReceipt = this.ocean.keeper.didRegistry.transferDIDOwnership(
+            did,
+            newOwner,
+            oldOwner
+        )
+        //get a signature
+        const signature=await this.ocean.utils.signature.signForAquarius(oldDdo.updated, account)
+        if(signature!=null)
+            await this.ocean.aquarius.transferOwnership(did,newOwner,oldDdo.updated,signature)
+
+        return txReceipt
     }
 
     /**
diff --git a/src/ocean/utils/SignatureUtils.ts b/src/ocean/utils/SignatureUtils.ts
index 9da6072..23d7beb 100644
--- a/src/ocean/utils/SignatureUtils.ts
+++ b/src/ocean/utils/SignatureUtils.ts
@@ -1,5 +1,6 @@
 import Web3 from 'web3'
 import { Logger } from '../../utils'
+import { Account } from '../../squid'
 
 export class SignatureUtils {
     private web3: Web3
@@ -40,4 +41,31 @@ export class SignatureUtils {
     public async verifyText(text: string, signature: string): Promise<string> {
         return this.web3.eth.personal.ecRecover(text, signature)
     }
+
+    public async getHash(message:string): Promise<string> {
+        var hex = ''
+        for(var i=0;i<message.length;i++) {
+            hex += ''+message.charCodeAt(i).toString(16)
+        }
+        var hexMessage = "0x" + hex
+        return hexMessage as string
+    }
+    public async signForAquarius(message:string, account:Account): Promise<string> {
+        const hash=await this.getHash(message)
+        const isMetaMask =
+            this.web3 &&
+            this.web3.currentProvider &&
+            (this.web3.currentProvider as any).isMetaMask
+        try {
+            return this.web3.eth.personal.sign(hash, account.getId(),account.getPassword())
+        } catch (e) {
+            if (isMetaMask) {
+                throw e
+            }
+            this.logger.warn('Error on personal sign.')
+            this.logger.warn(e)
+            return null
+        }
+        
+    }
 }