fix: improved message api

fix: Improved Crypto unit testing
fix: Moved "decode" to Convert.hexToUtf8
fix: EncryptedMessage payload wasn't reproducible.

Author: fboucquez

Diff for: CHANGELOG.md

@@ -13,7 +13,9 @@ SDK Core| v1.0.3 | [symbol-sdk](https://www.npmjs.com/package/symbol-sdk)
 Catbuffer | v1.0.1 | [catbuffer-typescript](https://www.npmjs.com/package/catbuffer-typescript)
 Client Library | v1.0.2  | [symbol-openapi-typescript-fetch-client](https://www.npmjs.com/package/symbol-openapi-typescript-fetch-client)
 
-- fix: replaced `instanceof` statements. These statements are problematic when npm installs the dependency in multiples modules. 
+- fix: Improved message API.
+- fix: EncryptedMessage payload wasn't reproducible.
+- fix: replaced `instanceof` statements. These statements are problematic when npm installs the dependency in multiples modules.
 
 ## [1.0.2] - 25-Oct-2021
 

Diff for: src/core/crypto/Crypto.ts

@@ -107,19 +107,25 @@ export class Crypto {
     /**
      * Encode a message using AES-GCM algorithm
      *
-     * @param {string} senderPriv - A sender private key
-     * @param {string} recipientPub - A recipient public key
-     * @param {string} msg - A text message
-     * @param {boolean} isHexString - Is payload string a hexadecimal string (default = false)
+     * @param senderPriv - A sender private key
+     * @param recipientPub - A recipient public key
+     * @param msg - A text message
+     * @param isHexString - Is payload string a hexadecimal string (default = false)
+     * @param iv - the iv for unit testing, otherwise a random 12 byte array.
+     *
      * @return {string} - The encoded message
      */
-    public static encode = (senderPriv: string, recipientPub: string, msg: string, isHexString = false): string => {
+    public static encode = (
+        senderPriv: string,
+        recipientPub: string,
+        msg: string,
+        isHexString = false,
+        iv = Crypto.randomBytes(12),
+    ): string => {
         // Errors
         if (!senderPriv || !recipientPub || !msg) {
             throw new Error('Missing argument !');
         }
-        // Processing
-        const iv = Crypto.randomBytes(12);
         const encoded = Crypto._encode(senderPriv, recipientPub, isHexString ? msg : convert.utf8ToHex(msg), iv);
         // Result
         return encoded;
@@ -171,7 +177,7 @@ export class Crypto {
         try {
             const decoded = Crypto._decode(recipientPrivate, senderPublic, payloadBuffer, tagAndIv);
             return decoded.toUpperCase();
-        } catch {
+        } catch (e) {
             // To return empty string rather than error throwing if authentication failed
             return '';
         }
@@ -183,7 +189,7 @@ export class Crypto {
      *
      * @return {Uint8Array}
      */
-    public static randomBytes = (length: number): any => {
+    public static randomBytes = (length: number): Buffer => {
         return crypto.randomBytes(length);
     };
 }

Diff for: src/core/format/Convert.ts

@@ -181,9 +181,26 @@ export class Convert {
      * @return {string}
      */
     public static utf8ToHex = (input: string): string => {
-        return Buffer.from(input, 'utf-8').toString('hex').toUpperCase();
+        return Convert.utf8ToBuffer(input).toString('hex').toUpperCase();
     };
 
+    /**
+     * Convert hex to UTF-8
+     * @param {string} hex - an hex string
+     * @return {string} An UTF-8 string
+     */
+    public static hexToUtf8 = (hex: string): string => {
+        return Buffer.from(hex, 'hex').toString();
+    };
+    /**
+     * Convert UTF-8 to buffer
+     * @param input - An UTF-8 string
+     * @return the buffer
+     */
+    public static utf8ToBuffer(input: string): Buffer {
+        return Buffer.from(input, 'utf-8');
+    }
+
     /**
      * Convert UTF-8 string to Uint8Array
      * @param {string} input - An string with UTF-8 encoding
@@ -266,4 +283,19 @@ export class Convert {
         }
         return value >>> 0;
     }
+    /**
+     * It concats a list of Uint8Array into a new one.
+     *
+     * @param arrays - the Uint8Array to concat.
+     */
+    public static concat(...arrays: Uint8Array[]): Uint8Array {
+        const totalLength = arrays.reduce((acc, value) => acc + value.length, 0);
+        const result = new Uint8Array(totalLength);
+        let length = 0;
+        for (const array of arrays) {
+            result.set(array, length);
+            length += array.length;
+        }
+        return result;
+    }
 }

Diff for: src/model/message/EncryptedMessage.ts

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import { GeneratorUtils } from 'catbuffer-typescript';
+import { Convert } from '../../core';
 import { Crypto } from '../../core/crypto';
 import { PublicAccount } from '../account';
 import { Message } from './Message';
@@ -23,26 +25,40 @@ import { PlainMessage } from './PlainMessage';
 /**
  * Encrypted Message model
  */
-export class EncryptedMessage extends Message {
-    public readonly recipientPublicAccount?: PublicAccount;
+export class EncryptedMessage implements Message {
+    public readonly type = MessageType.EncryptedMessage;
+    public readonly payload: string;
 
-    constructor(payload: string, recipientPublicAccount?: PublicAccount) {
-        super(MessageType.EncryptedMessage, payload);
-        this.recipientPublicAccount = recipientPublicAccount;
+    /**
+     * @internal
+     * @param buffer the buffer.
+     */
+    constructor(private readonly buffer: Uint8Array) {
+        this.payload = EncryptedMessage.getPayload(buffer);
     }
 
     /**
      *
      * @param message - Plain message to be encrypted
      * @param recipientPublicAccount - Recipient public account
      * @param privateKey - Sender private key
-     * @return {EncryptedMessage}
+     * @param iv - iv for encoding, for unit tests.
+     * @return The encrypted message.
+     */
+    public static create(message: string, recipientPublicAccount: PublicAccount, privateKey: string, iv?: Buffer): EncryptedMessage {
+        const encryptedHex = Crypto.encode(privateKey, recipientPublicAccount.publicKey, message, false, iv).toUpperCase();
+        return new EncryptedMessage(EncryptedMessage.createBuffer(encryptedHex));
+    }
+
+    /**
+     *
+     * @param encryptMessage - Encrypted message to be decrypted
+     * @param privateKey - Recipient private key
+     * @param recipientPublicAccount - Sender public account
+     * @return {PlainMessage}
      */
-    public static create(message: string, recipientPublicAccount: PublicAccount, privateKey: string): EncryptedMessage {
-        return new EncryptedMessage(
-            Crypto.encode(privateKey, recipientPublicAccount.publicKey, message).toUpperCase(),
-            recipientPublicAccount,
-        );
+    public static decrypt(encryptMessage: EncryptedMessage, privateKey: string, recipientPublicAccount: PublicAccount): PlainMessage {
+        return PlainMessage.create(Convert.hexToUtf8(Crypto.decode(privateKey, recipientPublicAccount.publicKey, encryptMessage.payload)));
     }
 
     /**
@@ -54,17 +70,44 @@ export class EncryptedMessage extends Message {
      * @param payload
      */
     public static createFromPayload(payload: string): EncryptedMessage {
-        return new EncryptedMessage(this.decodeHex(payload));
+        return new EncryptedMessage(EncryptedMessage.createBuffer(payload));
     }
 
     /**
      *
-     * @param encryptMessage - Encrypted message to be decrypted
-     * @param privateKey - Recipient private key
-     * @param recipientPublicAccount - Sender public account
-     * @return {PlainMessage}
+     * It creates the Plain message from a payload hex with the 00 prefix.
+     *
+     * @internal
+     */
+    public static createFromBuilder(builder: Uint8Array): EncryptedMessage {
+        return new EncryptedMessage(builder);
+    }
+
+    /**
+     * Create DTO object
      */
-    public static decrypt(encryptMessage: EncryptedMessage, privateKey, recipientPublicAccount: PublicAccount): PlainMessage {
-        return new PlainMessage(this.decodeHex(Crypto.decode(privateKey, recipientPublicAccount.publicKey, encryptMessage.payload)));
+    toDTO(): string {
+        return Convert.uint8ToHex(this.toBuffer());
+    }
+
+    toBuffer(): Uint8Array {
+        return this.buffer;
+    }
+
+    public static createBuffer(payload: string): Uint8Array {
+        if (!payload) {
+            return Uint8Array.of();
+        }
+        const message = Convert.utf8ToHex(payload);
+        const payloadBuffer = Convert.hexToUint8(message);
+        const typeBuffer = GeneratorUtils.uintToBuffer(MessageType.EncryptedMessage, 1);
+        return GeneratorUtils.concatTypedArrays(typeBuffer, payloadBuffer);
+    }
+
+    public static getPayload(buffer: Uint8Array): string {
+        if (!buffer.length) {
+            return '';
+        }
+        return Convert.uint8ToUtf8(buffer.slice(1));
     }
 }

Diff for: src/model/message/Message.ts

@@ -15,51 +15,29 @@ import { Convert } from '../../core/format/Convert';
  * limitations under the License.
  */
 
-import { Convert } from '../../core/format';
 import { MessageType } from './MessageType';
 
 /**
  * An abstract message class that serves as the base class of all message types.
  */
-export abstract class Message {
+export interface Message {
     /**
-     * @internal
-     * @param hex
-     * @returns {string}
+     * The buffer to be used when serializing a transaction
      */
-    public static decodeHex(hex: string): string {
-        return Buffer.from(hex, 'hex').toString();
-    }
+    toBuffer(): Uint8Array;
 
     /**
-     * @internal
-     * @param type
-     * @param payload
+     * Create DTO object
      */
-    constructor(
-        /**
-         * Message type
-         */
-        public readonly type: MessageType,
-        /**
-         * Message payload, it could be the message hex, encryped text or plain text depending on the message type.
-         */
-        public readonly payload: string,
-    ) {}
+    toDTO(): string;
 
     /**
-     * Create DTO object
+     * validate if the content is correct
+     */
+    readonly type: MessageType;
+
+    /**
+     * Payload without type prefix.
      */
-    toDTO(): string {
-        if (!this.payload) {
-            return '';
-        }
-        if (this.type === MessageType.PersistentHarvestingDelegationMessage) {
-            return this.payload;
-        }
-        if (this.type === MessageType.RawMessage) {
-            return this.payload;
-        }
-        return this.type.toString(16).padStart(2, '0').toUpperCase() + Convert.utf8ToHex(this.payload);
-    }
+    readonly payload: string;
 }

Diff for: src/model/message/MessageFactory.ts

@@ -34,31 +34,32 @@ export class MessageFactory {
      * @param payload the payload as byte array
      */
     public static createMessageFromBuffer(payload?: Uint8Array): Message {
-        return this.createMessageFromHex(payload ? Convert.uint8ToHex(payload) : undefined);
-    }
-    /**
-     * It creates a message from the hex payload
-     * @param payload the payload as hex
-     */
-    public static createMessageFromHex(payload?: string): Message {
         if (!payload || !payload.length) {
-            return new RawMessage('');
+            return RawMessage.create(Uint8Array.of());
         }
-        const upperCasePayload = payload.toUpperCase();
+        const messageType = payload[0];
+        const upperCasePayload = Convert.uint8ToHex(payload).toUpperCase();
         if (
             upperCasePayload.length == PersistentHarvestingDelegationMessage.HEX_PAYLOAD_SIZE &&
             upperCasePayload.startsWith(MessageMarker.PersistentDelegationUnlock)
         ) {
             return PersistentHarvestingDelegationMessage.createFromPayload(upperCasePayload);
         }
-        const messageType = Convert.hexToUint8(upperCasePayload)[0];
+
         switch (messageType) {
             case MessageType.PlainMessage:
-                return PlainMessage.createFromPayload(upperCasePayload.substring(2));
+                return PlainMessage.createFromBuilder(payload);
             case MessageType.EncryptedMessage:
-                return EncryptedMessage.createFromPayload(upperCasePayload.substring(2));
+                return EncryptedMessage.createFromBuilder(payload);
         }
-        return new RawMessage(upperCasePayload);
+        return RawMessage.create(payload);
+    }
+    /**
+     * It creates a message from the hex payload
+     * @param payload the payload as hex
+     */
+    public static createMessageFromHex(payload?: string): Message {
+        return MessageFactory.createMessageFromBuffer(payload ? Convert.hexToUint8(payload) : undefined);
     }
 }
 

Diff for: src/model/message/PersistentHarvestingDelegationMessage.ts

@@ -22,11 +22,15 @@ import { Message } from './Message';
 import { MessageMarker } from './MessageMarker';
 import { MessageType } from './MessageType';
 
-export class PersistentHarvestingDelegationMessage extends Message {
+export class PersistentHarvestingDelegationMessage implements Message {
+    public type = MessageType.PersistentHarvestingDelegationMessage;
     public static readonly HEX_PAYLOAD_SIZE = 264;
 
-    constructor(payload: string) {
-        super(MessageType.PersistentHarvestingDelegationMessage, payload.toUpperCase());
+    /**
+     * @internal
+     * @param payload
+     */
+    constructor(public readonly payload: string) {
         if (!Convert.isHexString(payload)) {
             throw Error('Payload format is not valid hexadecimal string');
         }
@@ -86,4 +90,15 @@ export class PersistentHarvestingDelegationMessage extends Message {
         const decrypted = Crypto.decode(privateKey, ephemeralPublicKey, payload);
         return decrypted.toUpperCase();
     }
+
+    /**
+     * Create DTO object
+     */
+    toDTO(): string {
+        return this.payload;
+    }
+
+    toBuffer(): Uint8Array {
+        return Convert.hexToUint8(this.payload);
+    }
 }