Use base32 for 2FA scratch token (#18384)

* Use base32 for 2FA scratch token
* rename Secure* to Crypto*, add comments

2 files changed, 27 insertions, 27 deletions

diff --git a/modules/util/util.go b/modules/util/util.go
index c2117a6525..90d0eca15c 100644
--- a/modules/util/util.go
+++ b/modules/util/util.go
@@ -137,8 +137,8 @@ func MergeInto(dict map[string]interface{}, values ...interface{}) (map[string]i
 	return dict, nil
 }
 
-// RandomInt returns a random integer between 0 and limit, inclusive
-func RandomInt(limit int64) (int64, error) {
+// CryptoRandomInt returns a crypto random integer between 0 and limit, inclusive
+func CryptoRandomInt(limit int64) (int64, error) {
 	rInt, err := rand.Int(rand.Reader, big.NewInt(limit))
 	if err != nil {
 		return 0, err
@@ -146,27 +146,27 @@ func RandomInt(limit int64) (int64, error) {
 	return rInt.Int64(), nil
 }
 
-const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+const alphanumericalChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
 
-// RandomString generates a random alphanumerical string
-func RandomString(length int64) (string, error) {
-	bytes := make([]byte, length)
-	limit := int64(len(letters))
-	for i := range bytes {
-		num, err := RandomInt(limit)
+// CryptoRandomString generates a crypto random alphanumerical string, each byte is generated by [0,61] range
+func CryptoRandomString(length int64) (string, error) {
+	buf := make([]byte, length)
+	limit := int64(len(alphanumericalChars))
+	for i := range buf {
+		num, err := CryptoRandomInt(limit)
 		if err != nil {
 			return "", err
 		}
-		bytes[i] = letters[num]
+		buf[i] = alphanumericalChars[num]
 	}
-	return string(bytes), nil
+	return string(buf), nil
 }
 
-// RandomBytes generates `length` bytes
-// This differs from RandomString, as RandomString is limits each byte to have
-// a maximum value of 63 instead of 255(max byte size)
-func RandomBytes(length int64) ([]byte, error) {
-	bytes := make([]byte, length)
-	_, err := rand.Read(bytes)
-	return bytes, err
+// CryptoRandomBytes generates `length` crypto bytes
+// This differs from CryptoRandomString, as each byte in CryptoRandomString is generated by [0,61] range
+// This function generates totally random bytes, each byte is generated by [0,255] range
+func CryptoRandomBytes(length int64) ([]byte, error) {
+	buf := make([]byte, length)
+	_, err := rand.Read(buf)
+	return buf, err
 }
diff --git a/modules/util/util_test.go b/modules/util/util_test.go
index e2e26b2627..b32cec23d9 100644
--- a/modules/util/util_test.go
+++ b/modules/util/util_test.go
@@ -120,20 +120,20 @@ func Test_NormalizeEOL(t *testing.T) {
 }
 
 func Test_RandomInt(t *testing.T) {
-	int, err := RandomInt(255)
+	int, err := CryptoRandomInt(255)
 	assert.True(t, int >= 0)
 	assert.True(t, int <= 255)
 	assert.NoError(t, err)
 }
 
 func Test_RandomString(t *testing.T) {
-	str1, err := RandomString(32)
+	str1, err := CryptoRandomString(32)
 	assert.NoError(t, err)
 	matches, err := regexp.MatchString(`^[a-zA-Z0-9]{32}$`, str1)
 	assert.NoError(t, err)
 	assert.True(t, matches)
 
-	str2, err := RandomString(32)
+	str2, err := CryptoRandomString(32)
 	assert.NoError(t, err)
 	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{32}$`, str1)
 	assert.NoError(t, err)
@@ -141,13 +141,13 @@ func Test_RandomString(t *testing.T) {
 
 	assert.NotEqual(t, str1, str2)
 
-	str3, err := RandomString(256)
+	str3, err := CryptoRandomString(256)
 	assert.NoError(t, err)
 	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{256}$`, str3)
 	assert.NoError(t, err)
 	assert.True(t, matches)
 
-	str4, err := RandomString(256)
+	str4, err := CryptoRandomString(256)
 	assert.NoError(t, err)
 	matches, err = regexp.MatchString(`^[a-zA-Z0-9]{256}$`, str4)
 	assert.NoError(t, err)
@@ -157,18 +157,18 @@ func Test_RandomString(t *testing.T) {
 }
 
 func Test_RandomBytes(t *testing.T) {
-	bytes1, err := RandomBytes(32)
+	bytes1, err := CryptoRandomBytes(32)
 	assert.NoError(t, err)
 
-	bytes2, err := RandomBytes(32)
+	bytes2, err := CryptoRandomBytes(32)
 	assert.NoError(t, err)
 
 	assert.NotEqual(t, bytes1, bytes2)
 
-	bytes3, err := RandomBytes(256)
+	bytes3, err := CryptoRandomBytes(256)
 	assert.NoError(t, err)
 
-	bytes4, err := RandomBytes(256)
+	bytes4, err := CryptoRandomBytes(256)
 	assert.NoError(t, err)
 
 	assert.NotEqual(t, bytes3, bytes4)