# Encrypting string to Sha1 in Homeyscript

**URL:** <https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380>\
**Category:** Questions & Help\
**Created:** [November 19, 2022, 2:42pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380 "2022-11-19T14:42:15Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![Uniamock](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/uniamock/32/17934_2.png) [@Uniamock](https://community.homey.app/u/Uniamock)\
**Post date:** [November 19, 2022, 2:42pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/1 "2022-11-19T14:42:16Z")

</div>

Hi,  
Anyone knows how to encrypt a string variable to Sha1?  
When encrypting to Base64 I use .toString(‘base64’), so wonder if there are anything similar available for Sha1 encryption?  
Hope someone can guide me 🙂  
Thx in advance

---

<div class="post-metadata">

**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [November 19, 2022, 2:50pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/2 "2022-11-19T14:50:36Z")

</div>

```auto
const crypto = (this.constructor.constructor('return process.mainModule.require')())('crypto');

function hash(string) {
  const hasher = crypto.createHash('sha1');
  hasher.update(string);
  return hasher.digest('hex');
}

console.log( hash('hello world') )

```

Of course, SHA1 isn’t an encryption algorithm but a hash function (and Base64 is an encoding method) 😉

---

<div class="post-metadata">

**Author:** ![Uniamock](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/uniamock/32/17934_2.png) [@Uniamock](https://community.homey.app/u/Uniamock)\
**Post date:** [November 19, 2022, 3:04pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/3 "2022-11-19T15:04:26Z")

</div>

It worked 🙂

First thank you - you saved my day.  
Second thanks for super fast reply…  
and third, you learned me something new today 🙂

---

<div class="post-metadata">

**Author:** ![Bananamoon](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@Bananamoon](https://community.homey.app/u/Bananamoon)\
**Post date:** [May 3, 2023, 4:09pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/4 "2023-05-03T16:09:02Z")

</div>

Hi,  
I have been using the same code to hash some information, but since a couple days Homeyscript gives an error on the crypto library.

This piece: `const crypto = (this.constructor.constructor('return process.mainModule.require')())('crypto');`  
does not work anymore:

```auto
TypeError: Cannot read properties of undefined (reading 'require')

```

I have rebooted the Homey Pro and rebooted the Homeyscript app without success. Also checked if I have the latest Homey Script version, which i do.

I hope someone (I’m looking at you @robertklep 😂 ) has a solution for this ☹

---

<div class="post-metadata">

**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [May 3, 2023, 5:04pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/5 "2023-05-03T17:04:06Z")

</div>

Looks like `process.mainModule` was dropped from Node.js (either because it’s been deprecated for a while now, or Athom has removed it intentionally).

If you need to calculate an SHA1 hash, the only solution I can think of right now is to add a pure-JS implementation of the SHA1 algorithm to your script:

```auto
const hs = Array.from(Array(16), (_, i) => i.toString(16));
const hsr = hs.slice().reverse();
const h2s = hs.join("").match(/../g), h2sr = hsr.join("").match(/../g);
const h2mix = hs.map((h, i) => `${hsr[i]}${h}`);
const hseq = h2s.concat(h2sr, h2mix).map(hex => parseInt(hex, 16));
const H = new Uint32Array(Uint8Array.from(hseq.slice(0, 20)).buffer);
const K = Uint32Array.from(
    [2, 3, 5, 10], v => Math.floor(Math.sqrt(v) * (2 ** 30)));
const F = [
    (b, c, d) => ((b & c) | ((~b >>> 0) & d)) >>> 0,
    (b, c, d) => b ^ c ^ d,
    (b, c, d) => (b & c) | (b & d) | (c & d),
    (b, c, d) => b ^ c ^ d,    
];
function rotl(v, n) {
    return ((v << n) | (v >>> (32 - n))) >>> 0;
}

function sha1(buffer) {
    const u8a = ArrayBuffer.isView(buffer) ?
          new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength) :
          new Uint8Array(buffer);
    const total = Math.ceil((u8a.length + 9) / 64) * 64;
    const chunks = new Uint8Array(total);
    chunks.set(u8a);
    chunks.fill(0, u8a.length);
    chunks[u8a.length] = 0x80;
    const lenbuf = new DataView(chunks.buffer, total - 8);
    const low = u8a.length % (1 << 29);
    const high = (u8a.length - low) / (1 << 29);
    lenbuf.setUint32(0, high, false);
    lenbuf.setUint32(4, low << 3, false);
    
    const hash = H.slice();
    const w = new Uint32Array(80);
    for (let offs = 0; offs < total; offs += 64) {
        const chunk = new DataView(chunks.buffer, offs, 64);
        for (let i = 0; i < 16; i++) w[i] = chunk.getUint32(i * 4, false);
        for (let i = 16; i < 80; i++) {
            w[i] = rotl(w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16], 1);
        }
        let [a, b, c, d, e] = hash;
        for (let s = 0; s < 4; s++) {
            for (let i = s * 20, end = i + 20; i < end; i++) {
                const ne = rotl(a, 5) + F[s](b, c, d) + e + K[s] + w[i];
                [a, b, c, d, e] = [ne >>> 0, a, rotl(b, 30), c, d];
            }
        }
        hash[0] += a; hash[1] += b; hash[2] += c; hash[3] += d; hash[4] += e;
    }
    const digest = new DataView(new ArrayBuffer(20));
    hash.forEach((v, i) => digest.setUint32(i * 4, v, false));
    return Buffer.from(digest.buffer).toString('hex');
}

```

([source](https://gist.github.com/bellbind/18ff65781512151f53ed6eb093bac0f9#file-sha1-js))

Usage example:

```auto
const hash = sha1('some input string');
console.log( hash );

```

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<div class="post-metadata">

**Author:** ![Bananamoon](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@Bananamoon](https://community.homey.app/u/Bananamoon)\
**Post date:** [May 4, 2023, 5:37am UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/6 "2023-05-04T05:37:05Z")

</div>

Thank you very much!

---

<div class="post-metadata">

**Author:** ![Gary\_Russell](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/gary_russell/32/79265_2.png) [@Gary\_Russell](https://community.homey.app/u/Gary_Russell)\
**Post date:** [July 1, 2023, 10:55pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/7 "2023-07-01T22:55:38Z")

</div>

> [@robertklep](#):
>
> ```auto
> const u8a = ArrayBuffer.isView(buffer) ?
> new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength) :
> new Uint8Array(buffer);
> 
> ```

I gave the code a try and found that it was not working as expected. The hash returned was for a blank value so whatever you passed would give the same results. With a bit of playing I found the above secion of code needed to be changed for it to work. Once I made the adjustment I tested the rest of the code against other sha1 hash generators and its working perfectly now:

```
const u8a = new Uint8Array(buffer.length);
for(i=0;i<buffer.length;i+=1) {
  u8a[i]=buffer.codePointAt(i);
}

```

---

<div class="post-metadata">

**Author:** ![robertklep](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/robertklep/32/160628_2.png) [@robertklep](https://community.homey.app/u/robertklep)\
**Post date:** [July 2, 2023, 6:42am UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/8 "2023-07-02T06:42:35Z")

</div>

Ah yes, the code assumes the input data is passed as a buffer, which won’t be the case with Homey.

In that case, a faster fix would be:

```auto
const u8a = ArrayBuffer.isView(buffer) ?
        new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength) :
        new Uint8Array(Buffer.from(buffer));

```

---

<div class="post-metadata">

**Author:** ![Gary\_Russell](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/gary_russell/32/79265_2.png) [@Gary\_Russell](https://community.homey.app/u/Gary_Russell)\
**Post date:** [July 2, 2023, 10:15pm UTC](https://community.homey.app/t/encrypting-string-to-sha1-in-homeyscript/72380/9 "2023-07-02T22:15:39Z")

</div>

> [@robertklep](#):
>
> ```auto
> const u8a = ArrayBuffer.isView(buffer) ?
> new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength) :
> new Uint8Array(Buffer.from(buffer));
> 
> ```

Thankyou very much - this really helps 🙂