[My asp.net learning process] Invoke a simple encryption method of a class library library

asp.net| encryption asp.net with a MD5 and SHA1 encryption class library!
The following are two cryptographic methods for calling this class library:

=====================

public string GetMD5 (string strdata)
{
Using the MD5 encryption method:
System.Security.Cryptography.MD5 MD5 = new System.Security.Cryptography.MD5CryptoServiceProvider ();
byte[] md5bytes = System.Text.Encoding.Default.GetBytes (strdata);
byte[] crystring = Md5.computehash (md5bytes);
String md5str = String. Empty;
for (int i=0;i<crystring.length;i++)
{
Md5str + = Crystring[i]. ToString ("X2");
}
return md5str;
}

public string Getencrypt (String strdata,string strtype)
{
Use the MD5 or SHA1 encryption method:
String strcrydata = String. Empty;
if (strtype.toupper () = = "SHA1")
{
Strcrydata = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile (strdata, "SHA1");
}
else if (strtype.toupper () = = "MD5")
{
Strcrydata = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile (strdata, "MD5");
}
return strcrydata;
}