Secure Digital Music Initiative (SDMI) Overview

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Secure Digital Music Initiative(SDMI) Overview

• Provided by Texas Instruments
• June, 2000

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What is SDMI?
Secure Digital Music Initiative SDMI

• SDMI is
• An architecture
• A set of reference models
• Applications Layer
• Licensed Compliant Module (LCM) Layer
• Portable Device (PD) Layer
• A set of requirements
• Security
• Robustness
• Content screening
• A work in progress

• SDMI is NOT
• A true standard
• A single file format
• A single cryptographic algorithm
• A single coder
• Designed for interoperability

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TI and SDMI

• SDMI grew out of a meeting at Comdex 98 that was
  sponsored by TI and the RIAA
• TI supports SDMI, and believes a programmable TI
  Digital Signal Processor (DSP) solution is the
  best choice for the changing SDMI environment
• TI was first to announce SDMI-compliant portable
  solutions (with Liquid Audio, FhG and SanDisk)
• SDMI-compliant portable players using TI DSPs are
  shipping now. The first SDMI-compliant player
  was the Sony VAIO Music Clip, which started
  shipping in the US in January 00.

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TI and SDMI (contd)

• The Verance Phase I watermark decoder will be
  available on TIs TMS320C54x DSPs in early 3Q00
• The TI C54x-based evaluation module (EVM) is one
  of the 3 platforms that Phase II proposers will
  use to implement their technology. Therefore
  SDMI Phase II will be available on C54x very soon
  after the Phase II technology is chosen.
• TI has been approved as an SDMI ID Assignment
  Authority and has been granted a block of 64-bit
  unique IDs for use in TI DSP-based devices with
  built-in flash memory

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SDMI-Compliant System Layers

• The Licensed Compliant Module (LCM) transfers
  content between SDMI-compliant applications (S/W
  jukeboxes, etc.) and portable devices (PDs) or
  portable media (PM). It is roughly equivalent to
  a device driver.
• The application may delegate screening and other
  functions to the LCM or other trusted task --
  this is simply one possible structure.

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SDMI Version 1.0 Reference Model

• The SDMI Version 1.0 Reference Model includes a
  host with application(s) and LCM(s) interfaced to
  a portable player and/or portable media.
• Inputs to the Reference Model may include CD,
  Electronic Music Distribution (EMD), portable
  media, DVD, etc.

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Screening

• The most important concept within SDMI
• Considered by the record labels to be a major
  concession
• Allows perpetual usage of current (legacy)
  content (existing CDs and MP3s, etc.), but legacy
  content must be screened, encrypted, and bound to
  a specific player or piece of media
• Designed to enable the secure distribution of
  new (watermarked) content
• Phase 2 technology will use watermarking or
  similar means to detect new content that has been
  illegally copied and distributed.

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SDMI Screening Timeline

• Phase I - begins when SDMI-compliant applications
  start to ship
• Verance (formerly Aris/Solana) watermarking
  technology selected for Phase I
• 3 bits decoded Phase 1 trigger plus two copy
  control bits (DVD-A CCI bits)
• All SDMI-compliant Phase I applications must
  implement screening for the Phase I trigger
• Phase II - begins when content providers start
  shipping content with the Phase I trigger and the
  Phase II technology
• Phase II technology should be selected late 2000
  or early 2001. Phase II proposals are due in
  June 2000.
• The Phase II technology may require re-marking
  (changing copy once to copy no more.
• When Phase II begins, applications will see the
  Phase I trigger and request an upgrade for the
  application to a Phase II application
• Users who decline the upgrade will only be able
  to play legacy content
• Users who upgrade will be able to play new
  content plus legacy content

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SDMI Phase 1 Content Flow and Usage

• The Biddle Diagram specifies the flow of
  content into, out of, and within the SDMI Domain,
  and specifies the Phase I screening process.

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The SDMI Version 1 Portable Device (PD)

• General Requirements A PD must
• Store all content in SDMI-protected form
• Observe content usage rules
• Only accept portable media with content in
  SDMI-protected format
• Inputs
• SDMI-protected content from an LCM or PM
• Embedded microphone, limited to mono, voice-grade
  (-3db _at_100 Hz, -60 dB _at_8 KHz. Microphone input
  must be stored in SDMI-protected form, and
  screened before it can be exported from the SDMI
  domain.
• Unprotected digital and analog inputs must be
  screened within the PD and stored in
  SDMI-protected form
• Outputs
• Analog output is allowed. Playback gt1.5 normal
  speed must be degraded or pitch-corrected.
  Output during seek (FF/rewind) must be noticeably
  degraded
• Unprotected digital output of content is not
  allowed

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IDs and Binding

• Binding Content must be bound
• To the portable memory (PM), if the PM is
  removable
• To the PD, if the PD has non-removable memory
• IDs IDs must be
• Readable by the LCM and PD
• Statistically or truly unique across all devices
  or components for a given manufacturer
• A minimum length of
• 128 bits, if randomly assigned
• 32 bits, if assigned by an appropriate authority
• Security must not depend on the secrecy of the ID

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Robustness (i.e., Security and Tamper-Proofing)

• Content
• Content must be maintained in a secure form at
  all times until it is played out
• No unprotected content on a user-accessible bus
  (PCMCIA, device bay, 1394, Cardbus, etc., EXCEPT
  unprotected digital playback (e.g., USB speakers)
  is permitted, limited to 16-bit stereo at 48 KHz
  or less.
• Bypass/Defeating Functions or Procedures
• No switches, jumpers, traces that can be cut,
  secret control functions, etc., that will access
  to unprotected content
• Software
• Must be secured or encrypted
• Must perform self-checking/authentication to
  prevent unauthorized modification
• Hardware
• Must protect keys/algorithms using hardware or
  software means
• Must be designed so that removing or replacing
  components cannot be done without risk of damage
• Must require professional tools and difficulty to
  defeat security functions

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SDMI Status -- June 1, 2000

• Current SDMI priorities (in rough priority order)
• Definition of testing methods and procedures for
  evaluating Phase II screening technology
  candidates
• Selection of Phase II technology
• Must detect that content has been compressed and
  then uncompressed
• Need not be watermarking
• Highest priority of record companies
• Discussions of the implications of screening on
  usability and the consumer experience
• May lead to temporary relaxation of screening
  procedures
• Discussion of SDMI requirements for wireless
  devices, and what constitutes a SDMI Portable
  Device
• Completion of final trademark and licensing
  agreement
• Requires agreement on what constitutes SDMI
  compliance
• Difficult liability issues still remain

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SDMI Information on the Web

• The SDMI Portable Device Specification, Part 1,
  Version 1.0, is available on the public area of
  the SDMI Web site at
• http//www.sdmi.org/
• Additional information including a FAQ and how
  to join SDMI is also available on the public area
  of the Web site. SDMI members are given a login
  name and password to access the private area of
  the Web site, where all SDMI documents are stored.