fix(messageToHash): support messages longer than 252 chars

package.json

@@ -56,6 +56,7 @@
     "swagger-client": "^3.18.4",
     "tweetnacl": "^1.0.3",
     "tweetnacl-auth": "^1.0.1",
+    "varuint-bitcoin": "^1.1.2",
     "websocket": "^1.0.34"
   },
   "repository": {

src/utils/crypto.ts

@@ -24,10 +24,10 @@
 import nacl, { SignKeyPair } from 'tweetnacl'
 import aesjs from 'aes-js'
 import { blake2b, Data } from 'blakejs'
+import { encode as varuintEncode } from 'varuint-bitcoin'
 
 import { str2buf } from './bytes'
 import { encode, decode, sha256hash } from './encoder'
-import { NotImplementedError } from './errors'
 
 export { sha256hash }
 
@@ -206,8 +206,7 @@ export function verify (
 export function messageToHash (message: string): Buffer {
   const p = Buffer.from('aeternity Signed Message:\n', 'utf8')
   const msg = Buffer.from(message, 'utf8')
-  if (msg.length >= 0xFD) throw new NotImplementedError('Message too long')
-  return hash(Buffer.concat([Buffer.from([p.length]), p, Buffer.from([msg.length]), msg]))
+  return hash(Buffer.concat([varuintEncode(p.length), p, varuintEncode(msg.length), msg]))
 }
 
 export function signMessage (message: string, privateKey: string | Buffer): Uint8Array {

test/unit/crypto.ts

@@ -98,6 +98,12 @@ describe('crypto', () => {
     const messageNonASCIISignatureAsHex = 'faa1bdb8a88c529be904036382705ed207bbdde00ece3bdb541f5986d57aebe7babe315a4d95f5882165c28bf41f6149430509ded1cc7dcd9b134e0e1d73cd0b'
     const messageNonASCIISignature = Buffer.from(messageNonASCIISignatureAsHex, 'hex')
 
+    const longMessage = 'test'.repeat(256)
+    const longMessageHash = Buffer.from('J9bibOHrlicf0tYQxe1lW69LdDAxETwPmrafKjjQwvs=', 'base64')
+
+    it('calculates a hash of a long message', () =>
+      expect(Crypto.messageToHash(longMessage)).to.eql(longMessageHash))
+
     describe('sign', () => {
       it('should produce correct signature of message', () => {
         const s = Crypto.signMessage(message, privateKey)