1. OpenSSL acceleration using Graphics Processing Units
Pedro Miguel Costa Saraiva

2. Introduction Cryptography: The study of security techniques
OpenSSL acceleration using Graphics Processing Units
Introduction
Cryptography: The study of security techniques
SSL: A set of rules governing authentication and encrypted client/server communication
De facto standard for secure electronic communications
Computationally intensive
Large volumes of SSL traffic impact performance
Pedro Miguel Costa Saraiva

3. OpenSSL acceleration using Graphics Processing Units
Introduction
GPU: A specialised processing unit designed to manipulate graphics
Originally used solely for graphics calculations
Recent developments enable its use for general purpose computing
Massive computational power
Pedro Miguel Costa Saraiva

4. Introduction OpenSSL Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Introduction
OpenSSL
Open-source implementation of the SSL and TLS protocols
Core-library implements a variety of cryptographic functions
Intensively used by an extremely large number of both open and proprietary applications
Pedro Miguel Costa Saraiva

5. Introduction Objectives Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Introduction
Objectives
Efficiently offload cryptographic operations onto a GPU
Add GPU functionality to OpenSSL
Lighten the load on the CPU
Pedro Miguel Costa Saraiva

6. Introduction Pedro Miguel Costa Saraiva Structure State of the art
OpenSSL acceleration using Graphics Processing Units
Introduction
Structure
State of the art
OpenSSL
GPU
Programming the GPU
OpenCL
CUDA
OpenCL vs CUDA
Main challenges
Implementation
Results
Conclusion
Pedro Miguel Costa Saraiva

7. State of the art OpenSSL Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
OpenSSL
Commercial-grade full-featured open source toolkit
Divided into libssl and libcrypto
Core library written in C
Supports accelerator hardware via engines
Pedro Miguel Costa Saraiva

8. State of the art GPU Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU
Massive parallel processing power
Roughly ten times the floating point capability of a high end CPU
Faster growth rate than CPUs
Pedro Miguel Costa Saraiva

9. State of the art GPU - Programming Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU - Programming
At the end of the 90s, graphics cards could not be programmed
Things changed in 2001 with the release of DirectX 8 and OpenGL
Programmers had to express their computations in terms of textures, vertices and shader programs
Pedro Miguel Costa Saraiva

10. State of the art GPU - Programming Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU - Programming
2006: NVIDIA created the CUDA framework
ATI created the CTM low-level framework
2008: NVIDIA and ATI joined the Khronos Group
Development of an industry standard for hybrid computing
OpenCL version 1.0 released in December 2008
Pedro Miguel Costa Saraiva

11. State of the art GPU - OpenCL Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU - OpenCL
Open, royalty-free standard for general purpose programming
Supports CPUs, GPUs, and other types of processors
Maintained by the non-profit consortium Khronos Group
Adopted by Intel, AMD, NVIDIA, and ARM Holdings
Pedro Miguel Costa Saraiva

12. State of the art GPU - OpenCL Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU - OpenCL
API for coordinating parallel computation across different processors
Cross-platform programming languages
Subset of ISO C99
Low performance on NVIDIA GPUs
Pedro Miguel Costa Saraiva

13. State of the art GPU - CUDA Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU - CUDA
Proprietary hardware and software architecture
Designed by NVIDIA
Manages computations on a GPU
API is programmed with “C for CUDA”
Third party wrappers available for other languages
Pedro Miguel Costa Saraiva

14. State of the art GPU - Main Challenges Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
State of the art
GPU - Main Challenges
Well suited to extremely parallel problems
Interaction between threads should be minimal
Diverging executions paths are slow
Limited memory
Slow memory swapping
Data-intensive operations are discouraged
No file or standard I/O operations
Pedro Miguel Costa Saraiva

15. Implementation Structure Pedro Miguel Costa Saraiva OpenSSL AES
OpenSSL acceleration using Graphics Processing Units
Implementation
Structure
OpenSSL
AES
RSA Key Generation
RSA Cipher
Pedro Miguel Costa Saraiva

16. Implementation OpenSSL Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
OpenSSL
ENGINE component supports alternative cryptography implementations
Supports dynamic loading of external engines
Pedro Miguel Costa Saraiva

17. Implementation OpenSSL Engine Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
OpenSSL Engine
Binding function defines supported algorithms
Pointers to functions implementing the defined algorithms
Pedro Miguel Costa Saraiva

18. Implementation AES Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
AES
CBC mode encryption cannot be parallelised
Previous ciphertext block is required to begin encryption of the next one
CBC mode decryption can be parallelised
All blocks are decrypted in parallel
ECB mode can be parallelised
Pedro Miguel Costa Saraiva

19. Implementation AES Pedro Miguel Costa Saraiva Initialisation Cipher
OpenSSL acceleration using Graphics Processing Units
Implementation
AES
Initialisation
Key expansion is performed on the CPU
Cipher
Initialises the GPU
Allocates host and GPU memory for input and output data
Pedro Miguel Costa Saraiva

20. Implementation AES Pedro Miguel Costa Saraiva Cipher
OpenSSL acceleration using Graphics Processing Units
Implementation
AES
Cipher
Input data transferred to the GPU memory
All data transferred at once
GPU Kernel is called
Output data is transferred from the GPU memory
Pedro Miguel Costa Saraiva

21. Implementation AES Pedro Miguel Costa Saraiva GPU Kernel
OpenSSL acceleration using Graphics Processing Units
Implementation
AES
GPU Kernel
For CBC encryption, a single thread is called
Encrypts every block serially
For CBC decryption and ECB operations, a thread is called for every block
All blocks are processed in parallel
Pedro Miguel Costa Saraiva

22. Implementation RSA Key Generation Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Key Generation
Generation function (CPU side)
Calls the GPU to generate a large amount of prime candidates
No more numbers are generated until the initial pool is exhausted
Pedro Miguel Costa Saraiva

23. Implementation RSA Key Generation Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Key Generation
Generation function (GPU call)
GPU RNG is initialised
Device memory is allocated
A large amount of threads is called to generate prime BIGNUMs
Pedro Miguel Costa Saraiva

24. Implementation RSA Key Generation Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Key Generation
Generation function (GPU kernel)
Random BIGNUM is generated
BIGNUM p is tested for primality
Miller-Rabin probabilistic primality test
BIGNUMs determined to be prime are written into global memory
Each thread tests one BIGNUM
Pedro Miguel Costa Saraiva

25. Implementation RSA Key Generation Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Key Generation
Generation function (GPU call)
Output data copied back to the host
Required implementing the entire OpenSSL BIGNUM library on the GPU
Pedro Miguel Costa Saraiva

26. Implementation RSA Cipher Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Cipher
BIGNUMs used in RSA must be broken down into small words
Multiple threads can each process a word
Chinese Remainder Theorem can split private key operations in half
Pedro Miguel Costa Saraiva

27. Implementation RSA Cipher Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Cipher
Multi-Precision Algorithm
K-bit integer A is broken into s k/64 words
O(s) parallel implementation
Runs s threads in two phases
Pedro Miguel Costa Saraiva

28. Implementation RSA Cipher Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Implementation
RSA Cipher
First phase accumulates s partial products in 2s steps
Carries accumulated in a separate array
Second phase adds the carries to the intermediate result\
Worst case scenario is s-1 iterations
Usually only one or two
Pedro Miguel Costa Saraiva

29. Results Testing Framework Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
Testing Framework
Intel Core i7 950 CP, 3.07GHz
NVIDIA GeForce GTX 580
Stress tool used on heavy CPU load tests
300 threads looping on sqrt, malloc/free and sync
Pedro Miguel Costa Saraiva

30. Results AES – CBC Decryption Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
AES – CBC Decryption
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

31. Results AES – CBC Encryption Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
AES – CBC Encryption
Slower than the CPU
Only 2.7% impact on CPU load
Pedro Miguel Costa Saraiva

32. Results AES – ECB Encryption Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
AES – ECB Encryption
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

33. Results AES – ECB Decryption Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
AES – ECB Decryption
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

34. Results RSA Key Generation Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
RSA Key Generation
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

35. Results RSA Key Generation – Heavy CPU load Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
RSA Key Generation – Heavy CPU load
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

36. Results RSA Cipher RSA Cipher Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
RSA Cipher
RSA Cipher
Single message
Slower until the amount of data reaches 3KB
Up to 43 times faster
Single message, heavy CPU load
Multiple messages (4096-bit)
Pedro Miguel Costa Saraiva

37. Results RSA Key Generation – Heavy CPU load Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
RSA Key Generation – Heavy CPU load
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

38. Results RSA Key Generation – Heavy CPU load Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Results
RSA Key Generation – Heavy CPU load
Slower until the amount of data reaches 3KB
Up to 43 times faster
Pedro Miguel Costa Saraiva

39. Conclusion Pedro Miguel Costa Saraiva
OpenSSL acceleration using Graphics Processing Units
Conclusion
Significant performance boost for AES ECB and CBC Decryption
AES CBC Encryption is slower, but significantly lighter on the CPU
RSA Key Generation is significantly faster for multiple keys
RSA Cipher is significantly slower
Pedro Miguel Costa Saraiva

40. Future Work Pedro Miguel Costa Saraiva AES CTR Cipher Mode
OpenSSL acceleration using Graphics Processing Units
Future Work
AES CTR Cipher Mode
OpenSSL implementation still unstable
Manager to cache RSA requests for more effective use of the GPU
Pedro Miguel Costa Saraiva