gen secure random num & hash

internal/passcode/passcode.go

@@ -0,0 +1,35 @@
+package passcode
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"math/big"
+	mrand "math/rand"
+	"strconv"
+)
+
+func GenSecureRandomNumber() int {
+
+	max := new(big.Int).SetInt64(900000)
+	offset := new(big.Int).SetInt64(100000)
+
+	num, err := rand.Int(rand.Reader, max)
+	if err == nil {
+		passcode := num.Add(num, offset).Int64()
+		return int(passcode)
+	} else {
+		fallbackPasscode := mrand.Intn(900000) + 100000
+		return fallbackPasscode
+	}
+
+}
+
+func HashPasscode() (int, [32]byte) {
+
+	passcode := GenSecureRandomNumber()
+	numStr := strconv.Itoa(passcode)
+	data := []byte(numStr)
+
+	return passcode, sha256.Sum256(data)
+
+}