Does PhotoStream send pictures encrypted over the Internet?

Question

When I'm on a public Wi-Fi network and my photos are being synced to Photo Stream, is there any way for someone on the same network to be able to see them? What about anyone else on the way to Apple's servers?

Answer 1

Yes, everything sent to or from iCloud is encrypted with SSL:

iCloud Security

iCloud secures your content by encrypting it when sent over the Internet, storing it in an encrypted format, and using secure tokens for authentication.

Encrypting content that is sent over the Internet

The following content is encrypted using SSL (Secure Sockets Layer) when sent over the Internet to or from iCloud:

• Photos in your Photo Stream
• Documents in the Cloud
• Backup data for your iOS device

...

Answer 2

It's not clear which parts are encrypted and which aren't. The connection to Amazon AWS is unencrypted.

Apple documentation says that all Photo Stream content is encrypted. Yet while using wireshark to fix my privatizing web proxy's Photo Stream connection, I observed that iPhoto's connection to Photo Stream via Amazon AWS is unencrypted over port 80. Here's the packet capture that shows the unencrypted header, request ID, access key, signature, and so forth:

GET /XXX?x-client-request-id=YYY&Expires=ZZZ&byte-range=54-1229619&AWSAccessKeyId=W WW&Signature=UUU HTTP/1.1
Host: us-nca-00001.s3-external-1.amazonaws.com:80
User-Agent: PhotoStreamAgent/40.34 CFNetwork/596.2.3 Darwin/12.2.0 (x86_64) (Macmini4%2C1)
Accept: */*
x-amz-date: Wed, 06 Feb 2013 22:37:58 GMT
Range: bytes=54-1229619
x-apple-request-uuid: 9F8EFA00-71F8-4799-9241-A8A15CF75079
Connection: close

HTTP/1.1 206 Partial Content
x-amz-id-2: XXX
x-amz-request-id: YYY
Date: Mon, 11 Feb 2013 23:09:17 GMT
Last-Modified: Mon, 11 Feb 2013 23:09:11 GMT
ETag: "ZZZ"
Accept-Ranges: bytes
Content-Range: bytes 54-1229619/1798693
Content-Type: application/octet-stream
Content-Length: 1229566
Connection: close
Server: AmazonS3

The content is "application/octet-stream" and I was not able to identify as gzipped or any other content -- I presume that its encrypted, but I am unable to determine this. Does anyone know what this is? Anyone know which encryption protocol Apple uses for Photo Stream? Or why Photo Stream is communicating with Amazon AWS over port 80?