This is a real problem, but it is partially accounted for: > To ensure that data is not corrupted traversing the network, use the Content-MD5 header. When you

This is a real problem, but it is partially accounted for: > To ensure that data is not corrupted traversing the network, use the Content-MD5 header. When you use this header, Amazon S3 checks the object against the provided MD5 value and, if they do not match, returns an error. Additionally, you can calculate the MD5 while putting an object to Amazon S3 and compare the returned ETag to the calculated MD5 value. It’s not as obvious with multipart uploads where each chunk is (iirc) individually checksumd and stored, but only a single md5 is returned in the “etag”