VLSI Design Project Project Proposal Team BUNI 2 !! - PowerPoint

							    VLSI Design Project
      Project Proposal
         Team BUNI 2!!


Team Members

Ben Doherty       Chris Campetti
Jeremy Gummeson   Phil Murray

                                   1
Proposal
   Create an encrypted audio steganography
    (information hiding) device
       Store a DES-encrypted message into an audio stream
       Resultant audio stream should have no detectable
        changes from original


   Allow encrypting/encoding as well as
    decoding/decrypting
       Public-key encrypted message subtly stored within a
        seemingly benign audio signal

                                                              2
System Overview




                         Control
 Audio Stream In   Steganographer   Audio Stream Out




                                                       3
Possible Applications
   On-the-Fly MIDI watermarking

   Compact implementations
       Wrist watches
       PDA’s

   Integration into SoC

   Inline internet phone message encoding
                                             4
Encoding Operation
   User generates DES key pair (via keygen program)

   Options are set in device via serial interface (most likely SPI)
     “Encode” Command
     DES public key
     Encoding key (to seed PRNG)
     Message


   Audio stream is presented to device along with control signals

   Modified audio stream output captured by external device


                                                                       5
Encoding Pseudocode
encode(short *audio_stream)
   /* obtain and encrypt message
    * for stego from register file */
   char *crypt_msg = des3_encrypt(REGFILE[msg], REGFILE[pubKey]);

  // seed PRNG using key from register file
  seed_prng(REGFILE[key]);

   // for every sample i in the audio_stream
   for(i = 0, j = 0; i < len(audio_stream); i++, j++)
        // get random number k in 0..3
        k = get_prn() % 4;
        // set bit k in sample i to equiv bit from crypt msg
        audio_stream[i].bit[k] = crypt_message.bit[j];
   end
end



                                                                    6
Decoding Operation
   Recipient knows DES private key from key generation

   Options are set in device for decoding
     “Decode” Command
     DES Private Key
     Decoding Key (must be identical to encoding key)


   Modified audio stream given to device along with control signals

   Output “scrubbed” audio stream

   Decoded/Decrypted message stored on device for later serial
    access

                                                                       7
Decoding Pseudocode
encode(u16_t *audio_stream)
   // Seed PRNG from key in register file
   seed_prng(REGFILE[key]);

  // For every sample i in the audio_stream
  for(i = 0, j = 0; i < len(audio_stream); i++, j++)
       // Obtain next random #
       k = get_prn() % 4;
       // Add bit k from stream sample i to cryptmsg
       cryptmsg.bit[j] = audio_stream[i].bit[k];
  end

   // decrypt message using private key in register file
   char *msg = des3_decrypt(cryptmsg,
                            REGFILE[privKey]);
   // save message to register file
   REGFILE[msg] = msg;
end

                                                           8
Design Components
   Pseudo-Random Number Generator (PRNG)

   OpenCores Triple-DES (3DES) Core

   Stego CODEC (Possibly separate)

   Register File

   SPI Configuration Interface
                                            9
Datapath Overview
                                 AUDIO_OUT




      AUDIO_IN

      AUDIO_CLK
                   Stego CODEC                  PRNG
     AUDIO_LRSEL




                    DES3 Crypt               Register File




                              SPI_SS

                             SPI_CLK
                                             SPI Interface
                             SPI_MOSI                        SPI_MISO




                                                                        10
Security
   Two levels of security: encryption (3DES) and
    obfuscation (Steganography)

   Emphasis on stealth
       Should not be detectable
           Operate only on data with sufficient magnitude in
            audio stream
       Research steganalysis algorithms


                                                                11
Emulation
   Put system in physical form
       FPGA (Altera Cyclone II)
       Should fit on a single chip
       All components in Verilog


   Get a feel for why system would be useful as
    a chip
       Audio DeviceA/D ConverterSystemStorage

                                                   12
Testing
   Can use same verification method developed
    for software simulation

   Don’t have to wait for system completion

   Hide the US constitution in an album
       Exhibit proper extraction of data from CD

   Fool a steganography detection program
                                                    13
Limitations
   Only works on decompressed audio streams

   Requires lossless compression for transmission
       Lossy compression would obliterate message due to
        encryption


   Surface data vs. message data
       Size ratio must be sufficient (ss/sm > R) in order to embed
        message into surface


                                                                      14
Rough Labor Estimate
   Emulation / Verification – Chris

   Datapath Design – Ben

   Cryptography – Jeremy

   Synthesis and Layout - Phil

                                       15
References
   Artz, Donavan “Digital Steganography: Hiding Data within Data”
            IEEE Internet Computing Magazine
            June 2001

   Mora, F; Torrubia, A “Perceptual Cryptography on MPEG Layer III Bit-Streams”
            IEEE Transactions on Consumer Electronics, Vol. 48 No. 4
            Novermber 2002

   Vasiltsov; Karpinskyy; Sagan “Development of VHDL-based Core with Embedded Steganography Function”
            Lviv-Slasko, Ukraine
            Feb 2003

   Adli; Nakao “Three Steganography Algorithms for MIDI Files”
             University of Ryukyus, Okinawa Japan
             Aug 2005




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