s3Helpers.js

if (sse) {
  headers = {
    "x-amz-server-side-encryption-customer-key": btoa(privateKey),
    "x-amz-server-side-encryption-customer-key-MD5": md5b64(privateKey),
    "x-amz-server-side-encryption-customer-algorithm": "AES256"
  };
}

function md5b64(data) {
    return CryptoJS
        .MD5(data)
        .toString(CryptoJS.enc.Base64);
}

HTTP.call('GET', objectUrl, {
  headers: headers,
  responseType: 'blob'
}, function (err, success) {});