diff --git a/base/mp_base64copy.sas b/base/mp_base64copy.sas
index 9a949e5..9b52876 100644
--- a/base/mp_base64copy.sas
+++ b/base/mp_base64copy.sas
@@ -76,7 +76,7 @@ run;
 
 %if &outfound=0 %then %do;
   filename &outref temp lrecl=2097088;
-%%end;
+%end;
 
 %if &action=ENCODE %then %do;
   data _null_;
@@ -84,12 +84,12 @@ run;
     retain line "";
     infile &inref recfm=F lrecl= 1 end=eof;
     input @1 stream $char1.;
-    file &outref lrecl=76;
+    file &outref recfm=N;
     substr(line,(_N_-(CEIL(_N_/57)-1)*57),1) = byte(rank(stream));
     if mod(_N_,57)=0 or EOF then do;
       if eof then b64=put(trim(line),$base64X76.);
       else b64=put(line, $base64X76.);
-      put b64;
+      put b64 + (-1) @;
       line="";
     end;
   run;
@@ -101,19 +101,13 @@ run;
     fileout = fopen("&outref",'O',3,'B');
     char= '20'x;
     do while(fread(filein)=0);
-      raw="1234";
+      length raw $4;
       do i=1 to 4;
         rc=fget(filein,char,1);
         substr(raw,i,1)=char;
       end;
-      val="123";
-      val=input(raw,$base64X4.);
-      do i=1 to 3;
-        length byte $1;
-        byte=byte(rank(substr(val,i,1)));
-        rc = fput(fileout, byte);
-      end;
-      rc =fwrite(fileout);
+      rc = fput(fileout,input(raw,$base64X4.));
+      rc = fwrite(fileout);
     end;
     rc = fclose(filein);
     rc = fclose(fileout);
diff --git a/tests/base/mp_base64copy.test.sas b/tests/base/mp_base64copy.test.sas
new file mode 100644
index 0000000..ec74803
--- /dev/null
+++ b/tests/base/mp_base64copy.test.sas
@@ -0,0 +1,67 @@
+/**
+  @file
+  @brief Testing mp_base64copy.sas macro
+
+  <h4> SAS Macros </h4>
+  @li mp_base64copy.sas
+  @li mp_assert.sas
+
+**/
+
+
+/* TEST 1 - regular base64 decode */
+
+%let string1=base ik ally;
+filename tmp temp;
+data _null_;
+  file tmp;
+  put "&string1";
+run;
+%mp_base64copy(inref=tmp, outref=myref, action=ENCODE)
+
+data _null_;
+  infile myref;
+  input;
+  put _infile_;
+run;
+%mp_base64copy(inref=myref, outref=mynewref, action=DECODE)
+data _null_;
+  infile mynewref lrecl=5000;
+  input;
+  put _infile_;
+  call symputx('string1_check',_infile_);
+  stop;
+run;
+%mp_assert(
+  iftrue=("&string1"="&string1_check"),
+  desc=Basic String Compare,
+  outds=work.test_results
+)
+
+
+/* multibyte string check */
+
+filename tmp2 temp;
+data _null_;
+  file tmp2;
+  put "'╤', '╔', '╗', '═', '╧', '╚', '╝', '║', '╟', '─', '┼', '║', '╢', '│'";
+run;
+%mp_base64copy(inref=tmp2, outref=myref2, action=ENCODE)
+
+%mp_base64copy(inref=myref2, outref=newref2, action=DECODE)
+data _null_;
+  infile newref2 lrecl=5000;
+  input;
+  list;
+  /* do not print the string to the log else viya 3.5 throws exception */
+  if trim(_infile_)=
+    "'╤', '╔', '╗', '═', '╧', '╚', '╝', '║', '╟', '─', '┼', '║', '╢', '│'"
+  then call symputx('check2',1);
+  else call symputx('check2',0);
+  stop;
+run;
+%mp_assert(
+  iftrue=("&check2"="1"),
+  desc=Double Byte String Compare,
+  outds=work.test_results
+)
\ No newline at end of file