Share on Google+Share on Google+

fj risco
How do I change a large string into hex and then into byte so that SHA1 can be applied to it?
0 Answer(s)      4 years and 8 months ago
Posted in : Java Beginners

I work with cellphones and deal with MEID numbers on a daily basis. So instead of searching online for a MEID (a hex number of length 14) to pseudo ESN (a hex number of length 8) calculator, I figured I can make my own program. The way to obtain a pESN from MEID is fairly simple in theory. For example, given MEID 0xA0000000002329, to make a pESN, SHA-1 needs to be applied to the MEID. SHA-1 on A0000000002329 gives e3be267a2cd5c861f3c7ea4224df829a3551f1ab. Take the last 6 hex numbers of this result, and append it to 0x80 - the result is 0x8051F1AB.

Now here is the code I have so far:

public void sha1() throws NoSuchAlgorithmException {

    String hexMEID = "A0000000002329";

    MessageDigest mDigest = MessageDigest.getInstance("SHA1");      

    byte[] result = mDigest.digest(hexMEID.getBytes());
    StringBuilder sb = new StringBuilder();

    for (int i = 0; i < result.length; i++) {
        sb.append(Integer.toString((result[i] & 0xff) + 0x100, 16).substring(1));


The problem is that using this method, SHA-1 on A0000000002329 gives a89b611b421f57705bd013297ce3fc835f706ab0 instead of e3be267a2cd5c861f3c7ea4224df829a3551f1ab. What am I doing wrong here??

Someone gave me a hint that the trick is to apply SHA-1 to the number representing the MEID, not the string representing the MEID. If this is true then how do I change my string into hex and then into byte so that SHA1 can give me the correct result???


View Answers

Related Tutorials/Questions & Answers:
Java Spring Hibernate Struts Training Retrieve database from the table dynamically in jsp from oracle using servlet What does core Java include? java What are some way to learn Java quickly? Is it required to learn Java before learning Java Script? Is it necessary to learn java script before learning PHP? Are HTML5 and Java Script boosts Java career? Is Java object oriented? Fingerprint application with Java Uninstall Oracle Virtual Box JSON to HashMap Free Java online Training I want example of Control Statement in Java ANSI Color Codes with Python Create a Program that Calculates Input What is difference between JDK,JRE and JVM? How to see ubuntu version on server? How to get Page Source in Selenium (WebDriver) using Java? The path to the driver executable must be set by the webdriver.gecko.driver system property parse data from a link in java Java Program Qns using BlueJ How to fix HAX Kernel Module Is Not Installed error? Installing Audacity Looking for code Logic to check track changes & Coments in MSWord, MSWordx, MSExcel, MSExcelx is ON/OFF Installing JDK on Mac SAX Parser exception ERROR 601 (42P00): Syntax error. Encountered Thread java.lang.NoClassDefFoundError: org/apache/commons/fileupload/FileItemFactory How to install Ubuntu 16.04 LTS? HttpServletRequest cannot be resolved to a type in eclipse - Solved Unhandled event loop exception GC overhead limit exceeded Spring Data jpa with apache phoenix Caused by: java.lang.IllegalArgumentException: Not a host:port pair: PBUF o.a.h.h.z.RecoverableZooKeeper - Possibly transient ZooKeeper, quorum= com.thinkaurelius.titan.diskstorage.hbase.HBaseStoreManager class not found com.thinkaurelius.titan.diskstorage.hbase.HBaseStoreManager not found How to download and install Java 8 on Windows? How to uninstall JDK 7? How to install gtk-doc-tools package in Ubuntu? How to install Oracle JDK 8 on Ubuntu? ejabberd_ctl.beam not found - Solved How to convert date to UTC format in Java? How to install autoconf, automake and libtool in Ubuntu 15.10? How to convert current date to mm dd yyyy format in Java? How to convert current date to dd mm yyyy format in Java? How to stop window closing in "internalFrameClosing" event. How to find list of all index in Neo4j? file location SASLError using PLAIN: not-authorized


Advertisement null