Cuando miras Amazonas RESTAuthentication puedes ver que no se usa un nonce:
Authorization = "AWS" + " " + AWSAccessKeyId + ":" + Signature;
Signature = Base64( HMAC-SHA1( YourSecretAccessKeyID, UTF-8-Encoding-Of( StringToSign ) ) );
StringToSign = HTTP-Verb + "\n" +
Content-MD5 + "\n" +
Content-Type + "\n" +
Date + "\n" +
CanonicalizedAmzHeaders +
CanonicalizedResource;
CanonicalizedResource = [ "/" + Bucket ] +
<HTTP-Request-URI, from the protocol name up to the query string> +
[ subresource, if present. For example "?acl", "?location", "?logging", or "?torrent"];
CanonicalizedAmzHeaders = <described below>
¿Esto no debería incluir un nonce? ¿Se protegen contra los ataques de repetición de otra manera? ¿Cómo?