In your app code, initialize the Supabase client with your project's URL and public key. You can find these in your Supabase project settings.
```javascript
import { createClient } from '@supabase/supabase-js';

const supabaseUrl = 'https://xyzcompany.supabase.co';
const supabaseKey = 'public-anon-key';
const supabase = createClient(supabaseUrl, supabaseKey);
```

Pick a solid encryption library based on your language or framework. For Node.js, you might go with crypto-js or the native crypto module.
```bash
npm install crypto-js
```

Encrypt the data before sending it to Supabase:
```javascript
import CryptoJS from 'crypto-js';

const encryptData = (data, secret) => {
return CryptoJS.AES.encrypt(data, secret).toString();
};

const secretKey = 'your-secret-key';
const encryptedData = encryptData('Sensitive Data', secretKey);
```

Insert the encrypted data into your Supabase database.
```javascript
const { data, error } = await supabase
.from('your-table')
.insert([{ sensitive_column: encryptedData }]);

if (error) console.error('Error:', error);
else console.log('Data saved:', data);
```

When you need to get the data back, decrypt it using the same secret key.
```javascript
const decryptData = (ciphertext, secret) => {
const bytes = CryptoJS.AES.decrypt(ciphertext, secret);
return bytes.toString(CryptoJS.enc.Utf8);
};

const { data, error } = await supabase
.from('your-table')
.select('sensitive_column');

if (error) console.error('Error:', error);
else {
const decryptedData = decryptData(data[0].sensitive_column, secretKey);
console.log('Decrypted Data:', decryptedData);
}
```