init: v1.0.0

grand/drng/entropy/entropy_source_time.go

@@ -0,0 +1,41 @@
+package entropy
+
+import (
+	"sync"
+
+	"xdx.jelly/xgcl/grand/drng/entropy/rdtsc"
+)
+
+// SysTimeEntropySource 系统时间熵源
+type SysTimeEntropySource struct {
+	mu sync.Mutex
+}
+
+// GetEntropy
+func (e *SysTimeEntropySource) GetEntropy(minEntropy int64, minEntropyInputLength int64, maxEntropyInputLength int64) ([]byte, error) {
+	//使用互斥锁保证熵源的独占性
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	// SysTimeEntropySource熵源的Markov测试min entropy ~ 0.58
+	// 因此向熵源最少要取minEntropy / 0.58 ~ 2*minEntropy
+	n := minEntropy << 1
+	if n < minEntropyInputLength {
+		n = minEntropyInputLength
+	}
+	entropy := make([]byte, n)
+	for i := int64(0); i < n; i++ {
+		// var b byte
+		// for j := 0; j < 8; j++ {
+		// 	t := rdtsc.GetCPUTimeStamp()
+		// 	// xor of the the last two bits are used.
+		// 	// for a rdtsc usually used 20~50 cycles.
+		// 	// b |= byte((t^(t>>1)^(t>>2)^(t>>3))&1) << j
+		// 	b |= byte(t&1) << j
+		// }
+		// entropy[i] = b
+
+		entropy[i] = byte(rdtsc.GetCPUTimeStamp())
+	}
+	return entropy, nil
+}