feat: enable arbitrary payloads for JWS (#126)

* feat: enable arbitrary payloads for JWS
* chore(test): add tests for JWS functions

package.json

@@ -29,7 +29,8 @@
   },
   "author": "Pelle Braendgaard <[email protected]>",
   "contributors": [
-    "Mircea Nistor <[email protected]>"
+    "Mircea Nistor <[email protected]>",
+    "Joel Thorstensson <[email protected]>"
   ],
   "license": "Apache-2.0",
   "jest": {

src/JWT.ts

@@ -61,6 +61,13 @@ export interface JWTDecoded {
   data: string
 }
 
+export interface JWSDecoded {
+  header: JWTHeader
+  payload: string
+  signature: string
+  data: string
+}
+
 export interface JWTVerified {
   payload: any
   doc: DIDDocument
@@ -86,6 +93,19 @@ function encodeSection(data: any): string {
 
 export const NBF_SKEW: number = 300
 
+function decodeJWS(jws: string): JWSDecoded {
+  const parts: RegExpMatchArray = jws.match(/^([a-zA-Z0-9_-]+)\.([a-zA-Z0-9_-]+)\.([a-zA-Z0-9_-]+)$/)
+  if (parts) {
+    return {
+      header: JSON.parse(base64url.decode(parts[1])),
+      payload: parts[2],
+      signature: parts[3],
+      data: `${parts[1]}.${parts[2]}`
+    }
+  }
+  throw new Error('Incorrect format JWS')
+}
+
 /**  @module did-jwt/JWT */
 
 /**
@@ -99,16 +119,13 @@ export const NBF_SKEW: number = 300
  */
 export function decodeJWT(jwt: string): JWTDecoded {
   if (!jwt) throw new Error('no JWT passed into decodeJWT')
-  const parts: RegExpMatchArray = jwt.match(/^([a-zA-Z0-9_-]+)\.([a-zA-Z0-9_-]+)\.([a-zA-Z0-9_-]+)$/)
-  if (parts) {
-    return {
-      header: JSON.parse(base64url.decode(parts[1])),
-      payload: JSON.parse(base64url.decode(parts[2])),
-      signature: parts[3],
-      data: `${parts[1]}.${parts[2]}`
-    }
+  try {
+    const jws = decodeJWS(jwt)
+    const decodedJwt: JWTDecoded = Object.assign(jws, { payload: JSON.parse(base64url.decode(jws.payload)) })
+    return decodedJwt
+  } catch(e) {
+    throw new Error('Incorrect format JWT')
   }
-  throw new Error('Incorrect format JWT')
 }
 
 /**
@@ -123,9 +140,10 @@ export function decodeJWT(jwt: string): JWTDecoded {
  *  @param    {Object}            header            optional object to specify or customize the JWS header
  *  @return   {Promise<Object, Error>}              a promise which resolves with a JWS string or rejects with an error
  */
-export async function createJWS(payload: any, signer: Signer, header: Partial<JWTHeader> = {}): Promise<string> {
+export async function createJWS(payload: string | any, signer: Signer, header: Partial<JWTHeader> = {}): Promise<string> {
   if (!header.alg) header.alg = defaultAlg
-  const signingInput: string = [encodeSection(header), encodeSection(payload)].join('.')
+  const encodedPayload = typeof payload === 'string' ? payload : encodeSection(payload)
+  const signingInput: string = [encodeSection(header), encodedPayload].join('.')
 
   const jwtSigner: SignerAlgorithm = SignerAlgorithm(header.alg)
   const signature: string = await jwtSigner(signingInput, signer)
@@ -174,7 +192,7 @@ export async function createJWT(
   return createJWS(fullPayload, signer, header)
 }
 
-function verifyJWSDecoded({ header, data, signature }: JWTDecoded, pubkeys: PublicKey | PublicKey[]): PublicKey {
+function verifyJWSDecoded({ header, data, signature }: JWSDecoded, pubkeys: PublicKey | PublicKey[]): PublicKey {
   if (!Array.isArray(pubkeys)) pubkeys = [pubkeys]
   const signer: PublicKey = VerifierAlgorithm(header.alg)(data, signature, pubkeys)
   return signer
@@ -192,7 +210,7 @@ function verifyJWSDecoded({ header, data, signature }: JWTDecoded, pubkeys: Publ
  *  @return   {PublicKey}                       The public key used to sign the JWS
  */
 export function verifyJWS(jws: string, pubkeys: PublicKey | PublicKey[]): PublicKey {
-  const jwsDecoded: JWTDecoded = decodeJWT(jws)
+  const jwsDecoded: JWSDecoded = decodeJWS(jws)
   return verifyJWSDecoded(jwsDecoded, pubkeys)
 }
 
@@ -234,7 +252,7 @@ export async function verifyJWT(
     payload.iss,
     options.auth
   )
-  const signer: PublicKey = await verifyJWSDecoded({ header, data, signature } as JWTDecoded, authenticators)
+  const signer: PublicKey = await verifyJWSDecoded({ header, data, signature } as JWSDecoded, authenticators)
   const now: number = Math.floor(Date.now() / 1000)
   if (signer) {
     const nowSkewed = now + NBF_SKEW

src/__tests__/JWT-test.ts

@@ -1,9 +1,11 @@
-import { createJWT, verifyJWT, decodeJWT, resolveAuthenticator, NBF_SKEW } from '../JWT'
+import { createJWT, verifyJWT, decodeJWT, createJWS, verifyJWS, resolveAuthenticator, NBF_SKEW } from '../JWT'
 import { TokenVerifier } from 'jsontokens'
 import SimpleSigner from '../SimpleSigner'
 import NaclSigner from '../NaclSigner'
 import { verifyJWT as naclVerifyJWT } from 'nacl-did'
 import MockDate from 'mockdate'
+import base64url from 'base64url'
+import { PublicKey } from 'did-resolver'
 
 const NOW = 1485321133
 MockDate.set(NOW * 1000 + 123)
@@ -334,6 +336,41 @@ describe('verifyJWT()', () => {
   })
 })
 
+describe('JWS', () => {
+
+  it('createJWS works with JSON payload', async () => {
+    const payload = { some: 'data' }
+    const jws = await createJWS(payload, signer)
+    expect(jws).toMatchSnapshot()
+    expect(JSON.parse(base64url.decode(jws.split('.')[1]))).toEqual(payload)
+  })
+
+  it('createJWS works with base64url payload', async () => {
+    // use the hex public key as an arbitrary payload
+    const encodedPayload = base64url.encode(Buffer.from(publicKey, 'hex'))
+    const jws = await createJWS(encodedPayload, signer)
+    expect(jws).toMatchSnapshot()
+    expect(jws.split('.')[1]).toEqual(encodedPayload)
+  })
+
+  it('verifyJWS works with JSON payload', async () => {
+    const payload = { some: 'data' }
+    const jws = await createJWS(payload, signer)
+    expect(verifyJWS(jws, { publicKeyHex: publicKey } as PublicKey))
+  })
+
+  it('verifyJWS works with base64url payload', async () => {
+    const encodedPayload = base64url.encode(Buffer.from(publicKey, 'hex'))
+    const jws = await createJWS(encodedPayload, signer)
+    expect(verifyJWS(jws, { publicKeyHex: publicKey } as PublicKey))
+  })
+
+  it('verifyJWS fails with bad input', async () => {
+    const badJws = 'abrewguer.fjreoiwfoiew.foirheogu.reoguhwehrg'
+    expect(() => verifyJWS(badJws, { publicKeyHex: publicKey } as PublicKey)).toThrow('Incorrect format JWS')
+  })
+})
+
 describe('resolveAuthenticator()', () => {
   const ecKey1 = {
     id: `${did}#keys-1`,

src/__tests__/__snapshots__/JWT-test.ts.snap

@@ -1,5 +1,9 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`JWS createJWS works with JSON payload 1`] = `"eyJhbGciOiJFUzI1NksifQ.eyJzb21lIjoiZGF0YSJ9.dblNz-7BVLknOFIBPmt5VTG0MDls_Q69WI8OfQuqNdUp4y50-b8Ubn0xujm1ijfmfqRunpks5TyWqgMsQkR_GQ"`;
+
+exports[`JWS createJWS works with base64url payload 1`] = `"eyJhbGciOiJFUzI1NksifQ.A_3Vet7D1DjqI3_kazPuHgFu2mtYXD4n6mZobC6lNYR5.n5ZZQZe1J7e76TGTLBpQO2R22JFoHDBi5ScfoxHz__Qy7Q6r3R11GdXmY_0ntFx6nC9QbDD19y8tTDMLUM4DAw"`;
+
 exports[`createJWT() ES256K creates a JWT with correct format 1`] = `
 Object {
   "data": "eyJ0eXAiOiJKV1QiLCJhbGciOiJFUzI1NksifQ.eyJpYXQiOjE0ODUzMjExMzMsInJlcXVlc3RlZCI6WyJuYW1lIiwicGhvbmUiXSwiaXNzIjoiZGlkOmV0aHI6MHhmM2JlYWMzMGM0OThkOWUyNjg2NWYzNGZjYWE1N2RiYjkzNWIwZDc0In0",