An Introduction to Cryptographic Hardware Design

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An Introduction to Cryptographic Hardware Design

• BITS C442T
• Seminar
• Ganesh T S
• 1999A3A7030
• 26th September, 2003

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Overview

• Cryptography in Action
• The What and Why of Cryptography
• Types of Cryptography Algorithms
• Implementation Platforms and Characteristics
• Research Trends Hardware Implementation
  Methodologies
• Research Trends Hardware Implementation
  Architectures

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Cryptography in Action

• Do you have an account on Hotmail?
• Have you seen the URL https//loginnet.passport.c
  om/ppsecure/md5auth.srf?lc1033
• when logging on to the service?
• Ever wondered how your passwords are kept secure
  on the IPC server?
• Why arent you supposed to give out your credit
  card number while chatting on Yahoo! Messenger?
• You will come to know the answers for all these
  questions, and much more, in this presentation.

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The What and Why of Cryptography

• The Internet is being used as a tool for
  commerce, and hence, security becomes a
  tremendously important issue
• Cryptography Science of writing in secret code
  to ensure security
• First documented use of cryptography in writing
  dates back to circa 1900 B.C. when an Egyptian
  scribe used non-standard hieroglyphs in an
  inscription

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The What and Why of Cryptography

• Security requirements to be met by cryptography
  algorithms
• Authentication The process of proving one's
  identity.
• Privacy/confidentiality Ensuring that no one can
  read the message except the intended receiver.
• Integrity Assuring the receiver that the
  received message has not been altered in any way
  from the original.
• Non-repudiation A mechanism to prove that the
  sender really sent this message.

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Types of Cryptography Algorithms
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Implementation Platforms

• Take algorithms, and the first thing that comes
  to your mind is coding it in, say, C.
• Devising the algorithms is a tough job, but not
  the HLL implementation.
• For example, the C code for the MD5 hash
  algorithm does not exceed 500 lines!
• What are the other implementation platforms?

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Implementation Platforms
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Which Platform?

• The choice of the implementation platform is
  driven by a multitude of factors, which include,
• Performance needed
• Development and per-unit costs
• Power consumption (Important in case of wireless
  devices!)
• Flexibility
• Physical Security
• Choice heavily depends on application
  requirements, but

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Platform Characteristics
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Reconfigurable Hardware and Cryptography

• Why Hardware?
• Software Implementations are too slow for time
  critical applications
• Hardware implementations are intrinsically more
  secure
• Why Reconfigurable?

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Reconfigurable Hardware and Cryptography

• Advantages of reconfigurable platforms
• Algorithm agility
• Algorithm Upgradability
• Architecture Efficiency
• Resource Efficiency
• Algorithm Modification
• Throughput (Relative to software)
• Cost Efficiency (Relative to ASICs)

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Hardware Implementation Methodologies

• HDL Designing done using FSM model
• Termed as CFSM (Cryptographic FSM)

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Hardware Implementation Methodologies

• Four basic components of a CFSM
• State Register
• Key Register
• Updating Logic
• Control Load Logic
• Modification of generic CFSM for implementing
  hash functions

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Hardware Implementation Methodologies

• CFSM for Hash Functions

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Hardware Implementation Architectures

• Multitude of architectures are in the research
  pipeline
• PipeRench
• Developed in CMU
• Pipelining for better performance
• Systolic Architectures
• Usage of vector processor architectures
• Developed for Montgomery multiplication and other
  similar algorithms commonly found in cryptography

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Hardware Implementation Architectures

• PipeRench
• Being developed at CMU since 1996
• Reconfigurable fabric for implementing
  cryptography algorithms
• Three important characteristics
• Hardware virtualization
• Pipelined datapaths for word based computations
• Zero apparent configuration time

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Hardware Implementation Architectures

• Hardware virtualization allows execution of
  configuration larger than size of physical fabric
• Pipeline stages are termed as stripes
• These stripes are time multiplexed into physical
  stripes
• Disadvantageous requirements
• Identical nature requirement of physical stripes
• Dataflow graphs cant have long cycles

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Hardware Implementation Architectures

• Systolic Architectures
• The concept of systolic processing combines a
  highly parallel array of identical processor may
  span several integrated circuit chips.
• A set of simple Processing Elements with regular
  and local connections takes external inputs and
  processes them in a predetermined manner in a
  pipelined fashion

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Hardware Implementation Architectures

• Systolic Architectures for Cryptography
• Bit-serial architecture
• processes one input bit during a clock cycle. Is
  well suited for low speed applications.
• Bit-parallel architecture
• processes one input word during a clock cycle.
  Well suited for high-speed applications, but is
  area-inefficient
• Digit-serial architecture
• attempts to utilize the best of both worlds. The
  speed of bit-parallel and the relative simplicity
  of bit-serial.
• Offers elegant and flexible solutions

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Thank You