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pigweed / third_party / github / kmackay / micro-ecc / a029d90af014078a5a58c27e6063abe16b289243
commita029d90af014078a5a58c27e6063abe16b289243[log] [tgz]
authorprabhukr <prabhukr@google.com>Wed Apr 19 08:17:51 2023 -0700
committerprabhukr <prabhukr@google.com>Wed Apr 19 08:37:17 2023 -0700
tree75c135df0aa8565cb7fa27f2f7a623cd63b4d9f0
parent13721361f72877decb07cc7747b7a104dbdb0656 [diff]
Update ARM inline assembly constraints.

Inline assembly in uECC_vli_add is underspecified; the output
registers are written to before the input registers are fully
consumed. Updating the constraints to include earlyclobber `&`.
1 file changed
tree: 75c135df0aa8565cb7fa27f2f7a623cd63b4d9f0
  1. examples/
  2. scripts/
  3. test/
  4. .gitignore
  5. asm_arm.inc
  6. asm_arm_mult_square.inc
  7. asm_arm_mult_square_umaal.inc
  8. asm_avr.inc
  9. asm_avr_mult_square.inc
  10. curve-specific.inc
  11. emk_project.py
  12. emk_rules.py
  13. library.properties
  14. LICENSE.txt
  15. platform-specific.inc
  16. README.md
  17. types.h
  18. uECC.c
  19. uECC.h
  20. uECC_vli.h
README.md

micro-ecc

A small and fast ECDH and ECDSA implementation for 8-bit, 32-bit, and 64-bit processors.

The static version of micro-ecc (ie, where the curve was selected at compile-time) can be found in the “static” branch.

Features

  • Resistant to known side-channel attacks.
  • Written in C, with optional GCC inline assembly for AVR, ARM and Thumb platforms.
  • Supports 8, 32, and 64-bit architectures.
  • Small code size.
  • No dynamic memory allocation.
  • Support for 5 standard curves: secp160r1, secp192r1, secp224r1, secp256r1, and secp256k1.
  • BSD 2-clause license.

Usage Notes

Point Representation

Compressed points are represented in the standard format as defined in http://www.secg.org/sec1-v2.pdf; uncompressed points are represented in standard format, but without the 0x04 prefix. All functions except uECC_decompress() only accept uncompressed points; use uECC_compress() and uECC_decompress() to convert between compressed and uncompressed point representations.

Private keys are represented in the standard format.

Using the Code

I recommend just copying (or symlink) the uECC files into your project. Then just #include "uECC.h" to use the micro-ecc functions.

For use with Arduino, you can use the Library Manager to download micro-ecc (Sketch=>Include Library=>Manage Libraries). You can then use uECC just like any other Arduino library (uECC should show up in the Sketch=>Import Library submenu).

See uECC.h for documentation for each function.

Compilation Notes

  • Should compile with any C/C++ compiler that supports stdint.h (this includes Visual Studio 2013).
  • If you want to change the defaults for any of the uECC compile-time options (such as uECC_OPTIMIZATION_LEVEL), you must change them in your Makefile or similar so that uECC.c is compiled with the desired values (ie, compile uECC.c with -DuECC_OPTIMIZATION_LEVEL=3 or whatever).
  • When compiling for a Thumb-1 platform, you must use the -fomit-frame-pointer GCC option (this is enabled by default when compiling with -O1 or higher).
  • When compiling for an ARM/Thumb-2 platform with uECC_OPTIMIZATION_LEVEL >= 3, you must use the -fomit-frame-pointer GCC option (this is enabled by default when compiling with -O1 or higher).
  • When compiling for AVR, you must have optimizations enabled (compile with -O1 or higher).
  • When building for Windows, you will need to link in the advapi32.lib system library.