我正在尝试加密和解密存储在SQL中的密码。解码时出现错误输入不是有效的Base-64字符串，因为它包含非Base 64字符，两个以上的填充字符或填充字符中的非法字符。在System.Convert.FromBase64_Decode中。

解密代码：

string userEmail = Email1.Text;
string userPass = passW.Text;
SqlConnection sqlcon = new SqlConnection("My connection")
string query = "Select * from users Where email= '" + userEmail + "'";
SqlDataAdapter sda = new SqlDataAdapter(query,sqlcon);
DataTable dtbl = new DataTable()
sda.Fill(dtbl);
if (dtbl.Rows.Count == 1)
{
    string savedPasswordHash = dtbl.Rows[0][1].ToString();
    savedPasswordHash.Replace("-","");
    byte[] hashBytes = Convert.FromBase64String(savedPasswordHash);
    byte[] salt = new byte[16];
    Array.Copy(hashBytes,salt,16);
    var pbkdf2 = new Rfc2898DeriveBytes(userPass,10000);
    byte[] hash = pbkdf2.GetBytes(20);
    int ok = 1;
    for (int i = 0; i < 20; i++)
        if (hashBytes[i + 16] != hash[i])
            ok = 0;
            if (ok == 1) //good creds & redirect

加密代码：

byte[] salt1;
new RNGCryptoServiceProvider().GetBytes(salt1 = new byte[16]);
var pbkdf21 = new Rfc2898DeriveBytes(EmailTextBox.Text,salt1,10000); 

byte[] hash1 = pbkdf21.GetBytes(20);
byte[] hashBytes1 = new byte[36];

Array.Copy(salt1,hashBytes1,16);
Array.Copy(hash1,16,20);

string savedPasswordHash1 = Convert.ToBase64String(hashBytes1);
string commString = $"UPDATE users SET NewPassword = ('{savedPasswordHash1}') where Email = ('{email2}')";
using (SqlConnection connect = new SqlConnection(constring))
{
    using (SqlCommand comm = new SqlCommand())
    {
        comm.Connection = connect;
        comm.CommandText = commString;
        connect.Open();
        comm.ExecuteNonQuery();
        connect.Close();
    } 

列的数据类型为nvarchar