android - payUmoney integration is giving an error -

after logging in, it's generating hash value, still giving error "some problem occurred! try again".

payumoneysdkinitilizer.paymentparam.builder builder =     new payumoneysdkinitilizer.paymentparam.builder();  builder.setamount(10.0)        .settnxid("0nf7" + system.currenttimemillis())        .setphone(<my phone>)        .setproductname("product_name")        .setfirstname(<my name>)        .setemail(<my email>)        .setsurl("https://www.payumoney.com/mobileapp/payumoney/success.php")        .setfurl("https://www.payumoney.com/mobileapp/payumoney/failure.php")        .setudf1("").setudf2("").setudf3("").setudf4("").setudf5("")        .setisdebug(false)        .setkey(<mykey>)        .setmerchantid(<my debug merchant id>);  string tnxid="0nf7" + system.currenttimemillis(); payumoneysdkinitilizer.paymentparam paymentparam = builder.build(); string hashsequence = "<...>|"+tnxid+"|10.0|product_name|<my name>|<my email>|||||||||||salt"; string servercalculatedhash= hashcal("sha-512", hashsequence); toast.maketext(getapplicationcontext(),                servercalculatedhash, toast.length_short).show(); paymentparam.setmerchanthash(servercalculatedhash); // calculateserversidehashandinitiatepayment(paymentparam); payumoneysdkinitilizer.startpaymentactivityforresult(trayactivity.this, paymentparam); 

---

public static string hashcal(string type, string str) {     byte[] hashseq = str.getbytes();     stringbuffer hexstring = new stringbuffer();     try {         messagedigest algorithm = messagedigest.getinstance(type);         algorithm.reset();         algorithm.update(hashseq);         byte messagedigest[] = algorithm.digest();         (int = 0; i<messagedigest.length; i++) {             string hex = integer.tohexstring(0xff &messagedigest[i]);             if (hex.length() == 1) { hexstring.append("0"); }             hexstring.append(hex);         }     } catch (nosuchalgorithmexception e) {         e.printstacktrace();     } return hexstring.tostring(); } 

you use in code:

.settnxid("0nf7" + system.currenttimemillis()) 

and later:

string tnxid="0nf7" + system.currenttimemillis(); 

probably not problem, want use 2 different values these (the time may change between 2 calls)? didn't want same tnxid in both cases?

---

transactionidprovider.java:

import java.util.locale;  public class transactionidprovider {      private final static string default_prefix = "id";      // convenient prime number incrementing counter     private final static long id_add = 0xf0ad;  // "f*ck off , die"      // 64b counter non-trivial start value     private static long idcounter = 0x0101f00ddeadbeefl;      /**      * returns id consisting of prefix string , 64b counter interleaved      * 32b per-4s-timestamp.      *       * may produce identical id (collision) when:      * 1) class reloaded within 4s      *    (to fix: serialize "idcounter" upon shutdown/restart of vm, or      *    modify prefix per start of vm)      * 2) more 2^64 ids requested within 4s (no fix, unexpected)      * 3) more 2^64 ids requested after cca. 550 years.      *    (no fix, unexpected)      * 4) more 1 static instance of transactionidprovider used      *    (two or more vms running app) (to fix put different prefix in      *    every vm/server running this)      *       * length of returned id prefix.length() + 24 alphanumeric symbols.      */     public static synchronized string getnewid(final string prefix) {         idcounter += id_add;    // increment counter         // 32b timestamp per ~4s (millis/4096) (good ~550 years)         final int timestamp = (int)(system.currenttimemillis()>>12);         final int idpart1 = (int)(idcounter>>32);         final int idpart2 = (int)(idcounter);         return string.format(locale.us, "%s%08x%08x%08x",                              prefix, idpart1, timestamp, idpart2);     }      public static string getnewid() {         return getnewid(default_prefix);     }  } 

not sure how usable one, , if id may long. feel free use/modify way wish.

also wonder, whether didn't forget important, can't recall anything.

the security aspect of 1 still quite weak, within 4s time span id simple addition, @ least it's not producing 1, 2, 3... series.

---

did found sdk docs, looks txnid may 25 chars long, have 1 char prefix only. or cut down on timestamp, using %07x in format , masking value 0x0fffffff, make repeat every ~34 years -> 2 letters prefix. or change counter 32b int, should still more enough, unless expect thousands of transactions per second -> remove 8 chars. or base32/base64 whole id shorten (depends alphabet legal content)...

or whatever... spent enough time this. hire pro.