1. Music2Share – Copyright- Compliant Music Sharing in P2P Systems T. Kalker, D.H.J. Epema, P.H. Hartel, R.L.Lagendijk and M.V. Steen, Proceedings of IEEE, vol. 92, no. 6, Jun. 2004 Presented by Peter

2. Introduction An architecture called Music2Share (M2S) is proposed in which secure content sharing and P2P networking coexist Explanations for the success of (illegal) music sharing over the Internet 1. Free access (underlying reason is the price of legal music is too high) 2. The choice of music on the major P2P networks is almost unlimited 3. Consumers are no longer interested in complete CD albums, but only in particular tracks 4. Fast connections to the Internet, which makes downloading (and uploading) music more convenient

3. Introduction Evidence for copy-right-compliant online music selling:  iTunes – US$0.99 per track, the popularity of iTunes shows that users are willing to pay for content if the online music services is sufficiently compelling Central-server based systems have the distinct disadvantage of a bandwidth bottleneck at central server(s) Online music service is better put in practice by Altnet (www.altnet.com), which operates as a sub-P2P network under KaZaa (www.kazaa.com) The authors believe that it is worthwhile and challenging from both a technical and an economical perspective to develop technologies that enable and legal music sharing over the Internet

4. Points of Departure - fingerprinting Used for audio identification In the case of Napster, text-based methods was used – easily be modified by ordinary users, not very successful in establishing secure identification Often based on psychoperceptual properties by representing the perceptually most relevant aspects of music In M2S, fingerprinting is used to identify and subsequently replace low-quality files with high-quality ones. Audio fingerprinting technologies are currently being offered by several companies such as Audible Magic, Relatable, Shazam and Philips

5. Points of Departure - decentralization The authors seek fully decentralized solutions – both for storing and accessing fingerprints The nodes in P2P network maintain their independence while providing the facilities for efficiently routing search requests to the appropriate nodes The P2P approach has already been successfully applied to building large-scale distributed storage systems such as CFS [10], Past [11], and OceanStore [12]

6. Points of Departure - problems 2 major problems 1. Current P2P systems do not support efficient content- based searching  Gnutella [13] do offer facilities for unstructured content-based searching but at the price of a (much) lower performance 2. Current P2P systems lack security  Do not offer payment, protection against unauthorized access, guaranteed quality, etc  Only recently research has started on building secure P2P networks  Initial attempts at commercial deployment of secure anonymous P2P systems such as Earth Station Five (www.es5.com)

7. Overview of M2S architecture

8. M2S Architecture – Content Management Three types of content:  Public content encrypted audio files Distributed and replicated across the machines of the M2S P2P network  Private content Unencrypted audio files Cannot be shared with other users  Nonauthorized content Files that cannot be reliably authenticated M2S strives to identify and authenticate these files by  External labeling (certificates)  Internal labeling (watermarking)  Recognition (fingerprinting)

9. M2S Architecture – Royalty Payment Altnet (www.altnet.com)www.altnet.com  Encourage users to download copyrighted files  More efficient content distribution  Audio files need to be encrypted  Difficult for a user to use the content on any other device M2S  The users are able to use the audio content for private use  Reduce the chance of unauthorized spreading of the content by identifying, tracking, and filtering as it flows over the M2S network

10. M2S Architecture – Content Authentication M2S network consists of a classical P2P network enhanced with a central trusted party (TP) Public database:  containing encrypted audio files  Assists the TP with establishing the identity and the quality of audio files in the private databases TP  Authenticates audio files base upon their identification  Attaches digital certificate for payment of royalties The M2S needs to establish the identity of audio files, and link this identity to a license system with an appropriate payment infrastructure

11. M2S Architecture – Content Authentication Three methods for the identification of audio files  By authorized upload  By watermark  By fingerprint

12. M2S Architecture – Audio File Upgrading M2S will automatically transfer the quality- assured file from the public database to the user’s private database, when  A user is in legal possession of the music file  This file is not of the best quality  An equivalent quality-assured version exists at an authorized server How to prevent a user (illegally) obtaining a bad-quality version of a song and using the upgrade mechanism of M2S?

13. M2S Architecture – Audio File Upgrading The authors claim that illegal trading on the M2S network itself is extremely difficult on a large scale Small scale trading (e.g. email) cannot be prevented Large-scale illegal trading on other type of network (KaZaa, Gnutella) cannot be prevented unless by legal action

14. Discussion and Analysis – P2P analysis KaZaa claims their software has been downloaded upwards of 230 million times The fraction of traffic on U.S. Internet backbone due to Gnutella in 2001 was about 1.2% M2S aims to give its users guarantees that if a music file exists it is found M2S will need to consider the second-generation deterministic, structured overlay networks that are based on distributed hash table (DHTs) Compare with existing P2P music-sharing protocol, M2S deviates in two ways:  An additional step for security (retrieving a decryption key)  A distributed implementation of a fuzzy fingerprint search engine

15. Discussion and Analysis – Coding analysis Watermark design emphasis on inaudibility and security Due to the use of quality-checking tools in M2S, content-dependent watermarks are used Challenge for M2S is reliable, lightweight, and automated quality control of audio files  Degradation of the embedded watermark may be taken as a rough quality tool  Error rate in fingerprint matching may serve as an indicator of quality  Still an active topic of research for M2S

16. Discussion and Analysis – Protocol analysis M2S assumes:  The music producers and the server(s) form a secure domain  The client is a secure application  Payment devices on the users’ machines are secure  Communication between the clients and the server(s) is secure  No security assumptions about the peers or the users

17. M2S protocol overview

18. Scenario 1: Upload 1. A music producer chooses some music, negotiates a watermark ID with the server, and upload it onto the server 2. The server calculates a certificate that will identify this authorized music uniquely 3. An audio fingerprint is calculated 4. The server chooses an encryption key and encrypts the music 5. Appropriate peers store the encrypted music and certificates for future reference 6. Other peers store (parts of) the fingerprints and pointers to the associated certificate on the central server

19. Scenario 2a: Explicit Download 1. A user requests some music from a client by metadata, by a watermark ID, or by a fingerprint 2. Assume the client receives a valid token from a smart card or some other secure payment device 3. Client receives key from server and decrypts the files 4. If forensic tracking is enable, the music is watermarked with the identity of the client and the embedding information is sent back to the user

20. Scenario 2b: Watermark Request Download 1. The user places some music without a certificate on his disk that is derived from private content 2. Watermark is retrieved and send to the server 3. Retrieval of quality-checking data by the watermark ID 4. Payment token is exchanged with the server 5. The file is replaced by a certified music file from M2S network

21. Scenario 2c: Fingerprint Request Download 1. The user places some music without a certificate on his disk that is derived from private content 2. Fail to retrieve watermark ID 3. The client computes the fingerprints 4. Send a request for identification to the network 5. Retrieval of quality-checking data by the fingerprint 6. Rest of this scenario proceeds as Scenario 2b

22. Conclusion A novel approach to music sharing on P2P network has been sketched From the viewpoint of the user:  M2S will offer a music-sharing network with no technical restriction on content that has been bought  M2S will assist the user in managing and upgrading of his own private content From the point of viewpoint of the content owner:  M2S offers an efficient music-distribution mechanism  All music sharing on the network is controlled and payment are guaranteed for all music trading The basic technologies for the proposed architecture are currently available However, the application of these technologies in the proposed music-sharing architecture still has to be worked out and refined