URLs de sinal para acessar Amazon S3 em Nodejs

npm install amazon-s3-url-signer

var sig= require('amazon-s3-url-signer');
var bucket = sig.urlSigner('my key', 'my secret');
var url = bucket.getUrl('PUT', 'somefile.png', 'mybucketonotheraccount', 10);

https://github.com/dyashkir/amazon-s3-url-signer