{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Action": "sts:AssumeRoleWithWebIdentity",
      "Principal": {
        "Federated": "www.amazon.com"
      },
      "Effect": "Allow",
      "Condition": {
        "StringEquals": {
           "www.amazon.com:app_id": "amzn1.application.123exemple456"
        }
      },
      "Sid": ""
    }
  ]
 }

      <form action="https://mon-application-bucket.s3.amazonaws.com" method="post" enctype="multipart/form-data" id="myform" role="form">
        <input type="hidden" name="AWSAccessKeyId" id="fld_AWSAccessKeyId">
        <input type="hidden" name="acl" id="fld_Acl">
        <input type="hidden" name="key" id="fld_Key">
        <input type="hidden" name="policy" id="fld_Policy">
        <input type="hidden" name="redirect" id="fld_Redirect">
        <input type="hidden" name="signature" id="fld_Signature">
        <input type="hidden" name="x-amz-security-token" id="fld_Token">
        <label for="file">Please select a file to upload</label>
        <input type="file" id="file" name="file">
        <input type="submit" name="monbouton" id="btn_submit"  class="btn btn-default">
      </form>