GM-Standards SM2/SM3/SM4 for Go

This is a SM2 sm2p256v1 implementation whose performance is similar like golang native NIST P256 under amd64, for implementation detail, please refer https://github.com/emmansun/gmsm/wiki.

This is also a SM3 implementation whose performance is similar like golang native SHA 256 under amd64, for implementation detail, please refer https://github.com/emmansun/gmsm/wiki/SM3%E6%80%A7%E8%83%BD%E4%BC%98%E5%8C%96.

For SM4 implementation, AES-NI is used under amd64.

SM2 encryption Benchmark

P-256/SM2(No tuning)
goos: windows
goarch: amd64
pkg: gmsm/sm2
BenchmarkLessThan32-6   	     210	   5665861 ns/op	   0.01 MB/s	 2601864 B/op	   27725 allocs/op
PASS
ok  	gmsm/sm2	5.629s

P-256/SM2(with P256/SM2 curve pure golang implementation)
goos: windows
goarch: amd64
pkg: gmsm/sm2
BenchmarkLessThan32_P256SM2-6   	    1027	   1169516 ns/op	    3874 B/op	      74 allocs/op
PASS
ok  	gmsm/sm2	1.564s

P-256/SM2(with P256/SM2 amd64 curve implementation, i think there are still improvement space for p256Sqr function)
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm2
BenchmarkLessThan32_P256SM2-6   	   10447	    115618 ns/op	    2357 B/op	      46 allocs/op
PASS
ok  	github.com/emmansun/gmsm/sm2	2.199s

P-256 (SM2 based on NIST P-256 curve)
goos: windows
goarch: amd64
pkg: gmsm/sm2
BenchmarkMoreThan32-6   	   13656	     86252 ns/op	    3141 B/op	      50 allocs/op
PASS
ok  	gmsm/sm2	4.139s

SM3 hash Benchmark

Pure golang version
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm3
BenchmarkHash8K-6   	   27097	     41112 ns/op	 199.26 MB/s	       0 B/op	       0 allocs/op
PASS
ok  	github.com/emmansun/gmsm/sm3	3.463s

ASM (non-AVX2) version
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm3
BenchmarkHash8K-6   	   35080	     33235 ns/op	 246.49 MB/s	       0 B/op	       0 allocs/op
PASS
ok  	github.com/emmansun/gmsm/sm3	3.102s

ASM AVX2 version
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm3
BenchmarkHash8K-6   	   53208	     22223 ns/op	 368.63 MB/s	       0 B/op	       0 allocs/op
PASS
ok  	github.com/emmansun/gmsm/sm3	1.720s 

SHA256 ASM AVX2 version
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm3
BenchmarkHash8K_SH256-6   	   68352	     17116 ns/op	 478.63 MB/s	       0 B/op	       0 allocs/op
PASS
ok  	github.com/emmansun/gmsm/sm3	3.043s    

SM4 Benchmark

Pure golang version
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm4
BenchmarkEncrypt-6   	 2671431	       441 ns/op	  36.28 MB/s	       0 B/op	       0 allocs/op
BenchmarkDecrypt-6   	 2709132	       440 ns/op	  36.40 MB/s	       0 B/op	       0 allocs/op
BenchmarkExpand-6    	 2543746	       471 ns/op	      16 B/op	       1 allocs/op

ASM AES-NI version
goos: windows
goarch: amd64
pkg: github.com/emmansun/gmsm/sm4
BenchmarkEncrypt-6   	 5076427	       235 ns/op	  68.09 MB/s	       0 B/op	       0 allocs/op
BenchmarkDecrypt-6   	 5122974	       236 ns/op	  67.71 MB/s	       0 B/op	       0 allocs/op
BenchmarkExpand-6    	 2583012	       469 ns/op	      16 B/op	       1 allocs/op
PASS
ok  	github.com/emmansun/gmsm/sm4	6.193s