diff --git a/integration/utils/ddo-metadata-generator.ts b/integration/utils/ddo-metadata-generator.ts
index 2a9ecb6..03e2f06 100644
--- a/integration/utils/ddo-metadata-generator.ts
+++ b/integration/utils/ddo-metadata-generator.ts
@@ -5,14 +5,10 @@ const metadata: Partial<MetaData> = {
         name: undefined,
         type: "dataset",
         description: "Weather information of UK including temperature and humidity",
-        size: "3.1gb",
         dateCreated: "2012-02-01T10:55:11+00:00",
         author: "Met Office",
         license: "CC-BY",
         copyrightHolder: "Met Office",
-        encoding: "UTF-8",
-        compression: "zip",
-        contentType: "text/csv",
         // tslint:disable-next-line
         workExample: "stationId,latitude,longitude,datetime,temperature,humidity423432fsd,51.509865,-0.118092,2011-01-01T10:55:11+00:00,7.2,68",
         files: [
diff --git a/src/ddo/MetaData.ts b/src/ddo/MetaData.ts
index 5664b4d..2a8e2b1 100644
--- a/src/ddo/MetaData.ts
+++ b/src/ddo/MetaData.ts
@@ -1,23 +1,74 @@
 export interface File {
+    /**
+     * File URL.
+     * @type {string}
+     */
     url: string
+
+    /**
+     * File index.
+     * @type {number}
+     */
+    index?: number
+
+    /**
+     * File checksum.
+     * @type {[type]}
+     */
     checksum?: string
+
+    /**
+     * Checksum hash algorithm.
+     * @type {[type]}
+     */
     checksumType?: string
+
+    /**
+     * File content length.
+     * @type {[type]}
+     */
     contentLength?: string
+
+    /**
+     * Resource ID (depending on the source).
+     * @type {[type]}
+     */
     resourceId?: string
+
+    /**
+     * File encoding.
+     * @type {string}
+     * @example "UTF-8"
+     */
+    encoding?: string
+
+    /**
+     * File compression (e.g. no, gzip, bzip2, etc).
+     * @type {string}
+     * @example "zip"
+     */
+    compression?: string
+
+    /**
+     * File format, if applicable.
+     * @type {string}
+     * @example "text/csv"
+     */
+    contentType?: string
 }
 
 /**
  * Base attributes of Assets Metadata.
  * @see https://github.com/oceanprotocol/OEPs/tree/master/8#base-attributes
  */
-export class MetaDataBase {
+export interface MetaDataBase {
 
     /**
      * Descriptive name of the Asset.
      * @type {string}
      * @example "UK Weather information 2011"
      */
-    public name: string
+    name: string
 
     /**
      * Type of the Asset. Helps to filter by the type of asset,
@@ -25,7 +76,7 @@ export class MetaDataBase {
      * @type {string}
      * @example "dataset"
      */
-    public type: "dataset" | "algorithm" | "container" | "workflow" | "other"
+    type: "dataset" | "algorithm" | "container" | "workflow" | "other"
 
     /**
      * Details of what the resource is. For a dataset, this attribute
@@ -33,28 +84,21 @@ export class MetaDataBase {
      * @type {string}
      * @example "Weather information of UK including temperature and humidity"
      */
-    public description?: string
+    description?: string
 
     /**
      * The date on which the asset was created or was added.
      * @type {string}
      * @example "2012-10-10T17:00:000Z"
      */
-    public dateCreated: string
-
-    /**
-     * Size of the asset (e.g. 18MB). In the absence of a unit (MB, kB etc.), kB will be assumed.
-     * @type {string}
-     * @example "3.1gb"
-     */
-    public size: string
+    dateCreated: string
 
     /**
      * Name of the entity generating this data (e.g. Tfl, Disney Corp, etc.).
      * @type {string}
      * @example "Met Office"
      */
-    public author: string
+    author: string
 
     /**
      * Short name referencing the license of the asset (e.g. Public Domain, CC-0, CC-BY, No License Specified, etc. ).
@@ -62,35 +106,14 @@ export class MetaDataBase {
      * @type {string}
      * @example "CC-BY"
      */
-    public license: string
+    license: string
 
     /**
      * The party holding the legal copyright. Empty by default.
      * @type {string}
      * @example "Met Office"
      */
-    public copyrightHolder?: string
-
-    /**
-     * File encoding.
-     * @type {string}
-     * @example "UTF-8"
-     */
-    public encoding?: string
-
-    /**
-     * File compression (e.g. no, gzip, bzip2, etc).
-     * @type {string}
-     * @example "zip"
-     */
-    public compression?: string
-
-    /**
-     * File format, if applicable.
-     * @type {string}
-     * @example "text/csv"
-     */
-    public contentType: string
+    copyrightHolder?: string
 
     /**
      * Example of the concept of this asset. This example is part
@@ -98,7 +121,7 @@ export class MetaDataBase {
      * @type {string}
      * @example "423432fsd,51.509865,-0.118092,2011-01-01T10:55:11+00:00,7.2,68"
      */
-    public workExample?: string
+    workExample?: string
 
     /**
      * Mapping of links for data samples, or links to find out more information.
@@ -117,7 +140,7 @@ export class MetaDataBase {
      *    },
      *  ]
      */
-    public links?: Array<{[name: string]: string}>
+    links?: Array<{[name: string]: string}>
 
     /**
      * The language of the content. Please use one of the language
@@ -125,7 +148,7 @@ export class MetaDataBase {
      * @type {String}
      * @example "en"
      */
-    public inLanguage?: string
+    inLanguage?: string
 
     /**
      * Keywords or tags used to describe this content. Multiple entries in a keyword
@@ -133,28 +156,28 @@ export class MetaDataBase {
      * @type {String}
      * @example "weather, uk, 2011, temperature, humidity"
      */
-    public tags?: string
+    tags?: string
 
     /**
      * Price of the asset.
      * @type {String}
      * @example 10
      */
-    public price: number
+    price: number
 
     /**
      * Array of File objects including the encrypted file urls and some additional information.
      * @type {File[]}
      */
-    public files: File[]
+    files: File[]
 
     /**
      * SHA3 hash of concatenated values: [list of all file checksums] + name + author + license + did
      * @type {string}
      */
-    public checksum?: string
+    checksum?: string
 
-    public encryptedFiles?: any
+    encryptedFiles?: any
 }
 
 /**
diff --git a/src/ocean/OceanAssets.ts b/src/ocean/OceanAssets.ts
index d41e15d..0107f3f 100644
--- a/src/ocean/OceanAssets.ts
+++ b/src/ocean/OceanAssets.ts
@@ -111,7 +111,12 @@ export class OceanAssets extends Instantiable {
                             ...metadata.base,
                             contentUrls: [],
                             encryptedFiles,
-                            files: undefined,
+                            files: metadata.base.files
+                                .map((file, index) => ({
+                                    ...file,
+                                    index,
+                                    url: undefined,
+                                })),
                         } as any,
                     },
                 },
diff --git a/test/testdata/MetaData.ts b/test/testdata/MetaData.ts
index 4cb7934..50630a8 100644
--- a/test/testdata/MetaData.ts
+++ b/test/testdata/MetaData.ts
@@ -5,14 +5,10 @@ export const metadataMock: MetaData = {
         name: "UK Weather information 2011",
         type: "dataset",
         description: "Weather information of UK including temperature and humidity",
-        size: "3.1gb",
         dateCreated: "2012-10-10T17:00:000Z",
         author: "Met Office",
         license: "CC-BY",
         copyrightHolder: "Met Office",
-        encoding: "UTF-8",
-        compression: "zip",
-        contentType: "text/csv",
         workExample: "423432fsd,51.509865,-0.118092,2011-01-01T10:55:11+00:00,7.2,68",
         files: [
             {