send/test/frontend/frontend.test.js

const FileSender = window.FileSender;
const FileReceiver = window.FileReceiver;
const FakeFile = window.FakeFile;
const assert = window.assert;
const server = window.server;
const hexToArray = window.hexToArray;
const arrayToHex = window.arrayToHex;
const sinon = window.sinon;

let file;
let encryptedIV;
let fileHash;
let secretKey;
let originalBlob;

describe('File Sender', function() {
  before(function() {
      server.respondImmediately = true;
      server.respondWith(
              'POST',
              '/upload',
              function(request) {
                const reader = new FileReader();
                reader.readAsArrayBuffer(request.requestBody.get('data'));

                reader.onload = function(event) {
                  file = this.result;
                }

                const responseObj = JSON.parse(request.requestHeaders['X-File-Metadata']);
                request.respond(
                  200,
                  {'Content-Type': 'application/json'},
                  JSON.stringify({url: 'some url', 
                                  id: responseObj.id,
                                  delete: responseObj.delete})
                )
              }
            )
  })

  it('Should get a loading event emission', function() {
      const file = new FakeFile('hello_world.txt', ['This is some data.'])
      const fs = new FileSender(file);
      let testLoading = true;

      fs.on('loading', isStillLoading => {
          assert(!(!testLoading && isStillLoading));
          testLoading = isStillLoading;
      })

      return fs.upload()
        .then(info => {
          assert(info);
          assert(!testLoading);
        })
        .catch(err => {
          console.log(err, err.stack);
          assert.fail();
        });
  })

  it('Should get a hashing event emission', function() {
    const file = new FakeFile('hello_world.txt', ['This is some data.'])
    const fs = new FileSender(file);
    let testHashing = true;

    fs.on('hashing', isStillHashing => {
        assert(!(!testHashing && isStillHashing));
        testHashing = isStillHashing;
    })

    return fs.upload()
        .then(info => {
          assert(info);
          assert(!testHashing);
        })
        .catch(err => {
          console.log(err, err.stack);
          assert.fail();
        });
  })

  it('Should get a encrypting event emission', function() {
    const file = new FakeFile('hello_world.txt', ['This is some data.'])
    const fs = new FileSender(file);
    let testEncrypting = true;

    fs.on('encrypting', isStillEncrypting => {
      assert(!(!testEncrypting && isStillEncrypting));
      testEncrypting = isStillEncrypting;
    })

    return fs.upload()
      .then(info => {
        assert(info);
        assert(!testEncrypting);
      })
      .catch(err => {
        console.log(err, err.stack);
        assert.fail();
      });
  })

  it('Should encrypt a file properly', function(done) {
    const newFile = new FakeFile('hello_world.txt', ['This is some data.'])
    const fs = new FileSender(newFile);
    fs.upload().then(info => {
      const key = info.secretKey;
      secretKey = info.secretKey;
      const IV = info.fileId;
      encryptedIV = info.fileId;
      
      const readRaw = new FileReader;
      readRaw.onload = function(event) {
        const rawArray = new Uint8Array(this.result);
        originalBlob = rawArray;

        window.crypto.subtle.digest('SHA-256', rawArray).then(hash => {
          fileHash = hash;
          window.crypto.subtle.importKey(
            'jwk',
            {
              kty: 'oct',
              k: key,
              alg: 'A128GCM',
              ext: true,
            },
            {
              name: 'AES-GCM'
            },
            true,
            ['encrypt', 'decrypt']
          )
          .then(cryptoKey => {
            window.crypto.subtle.encrypt(
              {
                name: 'AES-GCM',
                iv: hexToArray(IV),
                additionalData: hash,
                tagLength: 128
              },
              cryptoKey,
              rawArray
            )
            .then(encrypted => {
              assert(new Uint8Array(encrypted).toString() ===
                     new Uint8Array(file).toString());
              done();
            })
          })
        })
        
      }

      readRaw.readAsArrayBuffer(newFile);
    })
  })

});

describe('File Receiver', function() {

  class FakeXHR {
    constructor() {
      this.response = file;
      this.status = 200;
    }

    static setup() {
      FakeXHR.prototype.open = sinon.spy();
      FakeXHR.prototype.send = function () {
        this.onload();
      }

      FakeXHR.prototype.originalXHR = window.XMLHttpRequest;

      FakeXHR.prototype.getResponseHeader = function () {
        return JSON.stringify({
          aad: arrayToHex(new Uint8Array(fileHash)),
          filename: 'hello_world.txt',
          id: encryptedIV
        })
      }
      window.XMLHttpRequest = FakeXHR;
    }

    static restore() {
      // originalXHR is a sinon FakeXMLHttpRequest, since
      // fakeServer.create() is called in frontend.bundle.js
      window.XMLHttpRequest.prototype.originalXHR.restore();
    }
  }
  
  const cb = function(done) {
    if (file === undefined ||
        encryptedIV === undefined || 
        fileHash === undefined || 
        secretKey === undefined) {
      assert.fail('Please run file sending tests before trying to receive the files.');
      done();
    }

    FakeXHR.setup();
    done();
  }

  before(cb)

  after(function() {
    FakeXHR.restore();
  })

  it('Should decrypt properly', function() {
    const fr = new FileReceiver();
    location.hash = secretKey;
    return fr.download().then(([decrypted, name]) => {
      assert(name);
      assert(new Uint8Array(decrypted).toString() ===
                  new Uint8Array(originalBlob).toString())
    }).catch(err => {
      console.log(err, err.stack);
      assert.fail();
    })
  })

  it('Should emit decrypting events', function() {
    const fr = new FileReceiver();
    location.hash = secretKey;

    let testDecrypting = true;

    fr.on('decrypting', isStillDecrypting => {
      assert(!(!testDecrypting && isStillDecrypting));
      testDecrypting = isStillDecrypting;
    });

    fr.on('safe', isSafe => {
      assert(isSafe);
    })

    return fr.download().then(([decrypted, name]) => {
      assert(decrypted);
      assert(name);
      assert(!testDecrypting);
    }).catch(err => {
      console.log(err, err.stack);
      assert.fail();
    })
  })

  it('Should emit hashing events', function() {
    const fr = new FileReceiver();
    location.hash = secretKey;

    let testHashing = true;

    fr.on('hashing', isStillHashing => {
      assert(!(!testHashing && isStillHashing));
      testHashing = isStillHashing;
    });

    fr.on('safe', isSafe => {
      assert(isSafe);
    })

    return fr.download().then(([decrypted, name]) => {
      assert(decrypted);
      assert(name);
      assert(!testHashing);
    }).catch(err => {
      assert.fail();
    })
  })

  it('Should catch fraudulent checksums', function(done) {
    // Use the secret key and file hash of the previous file to encrypt,
    // which has a different hash than this one (different strings).
    const newFile = new FakeFile('hello_world.txt', 
                      ['This is some data, with a changed hash.'])
    const readRaw = new FileReader();
    
    readRaw.onload = function(event) {
      const plaintext = new Uint8Array(this.result);
      window.crypto.subtle.importKey(
        'jwk',
        {
          kty: 'oct',
          k: secretKey,
          alg: 'A128GCM',
          ext: true
        },
        {
          name: 'AES-GCM'
        },
        true,
        ['encrypt', 'decrypt']
      )
      .then(key => {
        // The file hash used here is the hash of the fake
        // file from the previous test; it's a phony checksum.
        return window.crypto.subtle.encrypt(
          {
            name: 'AES-GCM',
            iv: hexToArray(encryptedIV),
            additionalData: fileHash,
            tagLength: 128
          },
          key,
          plaintext
        )
      })
      .then(encrypted => {
        file = encrypted;
        const fr = new FileReceiver();
        location.hash = secretKey;

        fr.on('unsafe', isUnsafe => {
          assert(isUnsafe)
        })

        fr.on('safe', () => {
          // This event should not be emitted.
          assert.fail();
        })

        fr.download().then(() => {
          assert.fail();
          done();
        }).catch(err => {
          assert(1);
          done();
        })
      })
    }
    readRaw.readAsArrayBuffer(newFile);
  })

  it('Should not decrypt with an incorrect checksum', function() {
    FakeXHR.prototype.getResponseHeader = function () {
      return JSON.stringify({
        aad: 'some_bad_hashz',
        filename: 'hello_world.txt',
        id: encryptedIV
      })
    }

    const fr = new FileReceiver();
    location.hash = secretKey;

    return fr.download().then(([decrypted, name]) => {
      assert(decrypted);
      assert(name);
      assert.fail();
    }).catch(err => {
      assert(1);
    })
  })
  
})