c# - Unable to call com registered dll function in php -

i have completed com registration of dll file , showing in registry(which got after entering regedit in command prompt)
if use $obj1 = new com("encryptiondll.clsencryption"); getting no error
when trying access method(which declared public string in .net) getting following error php code
fatal error: call undefined method com::encrypt12() in c:\xampp\htdocs\test1\index.php on line 12
please help
below c# code used constract dll:

using system;  using system.collections.generic;  using system.io;  using system.linq;  using system.security.cryptography;  using system.text;  using system.threading.tasks;    namespace encryptiondll  {      public class clsencryption      {         public static void main(string[] args)          {                        }         public static string encrypt12(string plaintext)          {                asciiencoding textconverter = new asciiencoding();              byte[] key = textconverter.getbytes("2a1c907916add59edffb3a4b");              byte[] iv = textconverter.getbytes("00000000");              byte[] cleardata = encoding.ascii.getbytes(plaintext);              byte[] cipherdata = encrypt1(cleardata, key, iv);              return convert.tobase64string(cipherdata);          }          public static byte[] encrypt1(byte[] cleardata, byte[] key, byte[] iv)          {                memorystream ms = new memorystream();              tripledescryptoserviceprovider tdes = new tripledescryptoserviceprovider();              tdes.mode = ciphermode.ecb;              tdes.padding = paddingmode.pkcs7;              icryptotransform alg = tdes.createencryptor(key, iv);              cryptostream cs = new cryptostream(ms, alg, cryptostreammode.write);              cs.write(cleardata, 0, cleardata.length);              cs.flushfinalblock();              cs.close();              byte[] encrypteddata = ms.toarray();              return encrypteddata;          }      }  }