1 files changed, 96 insertions, 0 deletions
diff --git a/crypto/secp256k1/secp256_rand.go b/crypto/secp256k1/secp256_rand.go
new file mode 100644
index 000000000..5e8035e0f
--- /dev/null
+++ b/crypto/secp256k1/secp256_rand.go
@@ -0,0 +1,96 @@
+package secp256k1
+
+import (
+	crand "crypto/rand"
+	"io"
+	mrand "math/rand"
+	"os"
+	"strings"
+	"time"
+)
+
+/*
+Note:
+
+- On windows cryto/rand uses CrytoGenRandom which uses RC4 which is insecure
+- Android random number generator is known to be insecure.
+- Linux uses /dev/urandom , which is thought to be secure and uses entropy pool
+
+Therefore the output is salted.
+*/
+
+//finalizer from MurmerHash3
+func mmh3f(key uint64) uint64 {
+	key ^= key >> 33
+	key *= 0xff51afd7ed558ccd
+	key ^= key >> 33
+	key *= 0xc4ceb9fe1a85ec53
+	key ^= key >> 33
+	return key
+}
+
+//knuth hash
+func knuth_hash(in []byte) uint64 {
+	var acc uint64 = 3074457345618258791
+	for i := 0; i < len(in); i++ {
+		acc += uint64(in[i])
+		acc *= 3074457345618258799
+	}
+	return acc
+}
+
+var _rand *mrand.Rand
+
+func init() {
+	var seed1 uint64 = mmh3f(uint64(time.Now().UnixNano()))
+	var seed2 uint64 = knuth_hash([]byte(strings.Join(os.Environ(), "")))
+	var seed3 uint64 = mmh3f(uint64(os.Getpid()))
+
+	_rand = mrand.New(mrand.NewSource(int64(seed1 ^ seed2 ^ seed3)))
+}
+
+func saltByte(buff []byte) []byte {
+	for i := 0; i < len(buff); i++ {
+		var v uint64 = uint64(_rand.Int63())
+		var b byte
+		for j := 0; j < 8; j++ {
+			b ^= byte(v & 0xff)
+			v = v >> 8
+		}
+		buff[i] = b
+	}
+	return buff
+}
+
+//On Unix-like systems, Reader reads from /dev/urandom.
+//On Windows systems, Reader uses the CryptGenRandom API.
+
+//use entropy pool etc and cryptographic random number generator
+//mix in time
+//mix in mix in cpu cycle count
+func RandByte(n int) []byte {
+	buff := make([]byte, n)
+	ret, err := io.ReadFull(crand.Reader, buff)
+	if len(buff) != ret || err != nil {
+		return nil
+	}
+
+	buff2 := RandByteWeakCrypto(n)
+	for i := 0; i < n; i++ {
+		buff[i] ^= buff2[2]
+	}
+	return buff
+}
+
+/*
+	On Unix-like systems, Reader reads from /dev/urandom.
+	On Windows systems, Reader uses the CryptGenRandom API.
+*/
+func RandByteWeakCrypto(n int) []byte {
+	buff := make([]byte, n)
+	ret, err := io.ReadFull(crand.Reader, buff)
+	if len(buff) != ret || err != nil {
+		return nil
+	}
+	return buff
+}