====== Hash Sample Code ======
 [[https://javacardos.com/javacardforum/download/file.php?id=540|Download Sample Code]]                   [[ http://javacardos.com/javacardforum/viewtopic.php?f=31&t=739|Discussion]] 


<code java>

/*
 * @file  HashSample.java
 *  @version v1.0
 * Package AID: 4A617661436172644F53
 * Applet AID:  4A617661436172644F5305
 * @brief The ALgorithm of Hash Sample Code in JavaCard API Specification
 * @comment The purpose of this example is only used to show the usage of API functions and there is no practical significance.
 * @copyright Copyright(C) 2016 JavaCardOS Technologies Co., Ltd. All rights reserved.
 */
  
package JavaCardOS.Sample.Algorithm;
 
import javacard.framework.*;
import javacard.security.*;
import javacardx.crypto.*;
 
public class HashSample extends Applet
{
    private static final byte INS_GEN_HASH = (byte)0x50;
 
    private byte[] flags;
    private static final short OFF_INS    = (short)0;
    private static final short OFF_P1     = (short)1;
    private static final short OFF_P2     = (short)2;
    private static final short OFF_LEN    = (short)3;
    private static final short FLAGS_SIZE = (short)5;
     
    private InitializedMessageDigest sha1;
    private InitializedMessageDigest sha256;
    private InitializedMessageDigest sha512;
     
    public HashSample()
    {
        flags = JCSystem.makeTransientByteArray(FLAGS_SIZE, JCSystem.CLEAR_ON_DESELECT);
        //Creates a InitializedMessageDigest object instance of the ALG_SHA algorithm.
        sha1 = MessageDigest.getInitializedMessageDigestInstance(MessageDigest.ALG_SHA, false);
        //Creates a InitializedMessageDigest object instance of the ALG_SHA_256 algorithm.
        sha256 = MessageDigest.getInitializedMessageDigestInstance(MessageDigest.ALG_SHA_256, false);
        //Creates a InitializedMessageDigest object instance of the ALG_SHA_512 algorithm.
        sha512 = MessageDigest.getInitializedMessageDigestInstance(MessageDigest.ALG_SHA_512, false);
        JCSystem.requestObjectDeletion();
    }
    public static void install(byte[] bArray, short bOffset, byte bLength)
    {
        new HashSample().register(bArray, (short) (bOffset + 1), bArray[bOffset]);
    }
 
    public void process(APDU apdu)
    {
        if (selectingApplet())
        {
            return;
        }
 
        byte[] buf = apdu.getBuffer();
        short len = apdu.setIncomingAndReceive();
        switch (buf[ISO7816.OFFSET_INS])
        {
        case (byte)INS_GEN_HASH:
            generateHash(apdu, len);
            break;
        default:
            ISOException.throwIt(ISO7816.SW_INS_NOT_SUPPORTED);
        }
    }
     
    //Generate Hash
    private void generateHash(APDU apdu, short len)
    {
        byte[] buffer = apdu.getBuffer();
        boolean hasMoreCmd = (buffer[ISO7816.OFFSET_P1] & 0x80) != 0;
        InitializedMessageDigest hash = null;
        short resultLen = 0;
        short offset = ISO7816.OFFSET_CDATA;
        switch (buffer[ISO7816.OFFSET_P1] & 0x7f)
        {
        case 0:
            hash = sha1;
            resultLen = MessageDigest.LENGTH_SHA;
            break;
        case 1:
            hash = sha256;
            resultLen = MessageDigest.LENGTH_SHA_256;
            break;
        case 2:
            hash = sha512;
            resultLen = MessageDigest.LENGTH_SHA_512;
            if (hash == null)
            {
                ISOException.throwIt(ISO7816.SW_CONDITIONS_NOT_SATISFIED);
            }
            break;
        default:
            ISOException.throwIt(ISO7816.SW_INCORRECT_P1P2);
            break;
        }
 
        if (buffer[ISO7816.OFFSET_P2] == 0) //first block
        {
            //Reset the MessageDigest object to the initial state.
            hash.reset();
        }
 
        if (hasMoreCmd)
        {
            //Accumulate a hash of the input data.
            hash.update(buffer, offset, len);
        }
        else
        {
            //Generate a hash of all the input data.
            short ret = hash.doFinal(buffer, offset, len, buffer, (short)0);
            Util.arrayFillNonAtomic(flags, (short)0, (short)flags.length, (byte)0);
            apdu.setOutgoingAndSend((short)0, ret);
        }
    }
 
}
</code>
The test script of Hash is as follows:                                   [[http://javacardos.com/javacardforum/download/file.php?id=545| Download Test Script]]
<code java>

//The test script of Hash
//Copyright(C) JavaCardOS Technologies Co., Ltd. All rights reserved.
 
//Hash Select Applet
00A404000B4A617661436172644F530500;
//SHA1
//expect:44ABF22AF275548BCE3639C5FE3CDFCFFFF305AA9000
80500000A36713E26AA669E98027D9FE54B457551A40599E921D39DB8970DA6FA2E18E785697375F3A63ADAE803B6021C1EB3FFFFA07D8AAD424C075284735B7C29E021E656EA345104DAA8880916117F608B1493AEA4233E00BE47ACA552E65EE76643659D69EBB74CC2720871124077B7576DAE4D0E1603F3C6D8F77810CA2AFD17E6B3BB672E9EF48EE1D9DA3F01AD998565CFFA3FB5A781D235E38B319958B17166212F565F8;
//SHA256
80508100C8ECE47FD746C16AD454D0D509979BF65DB051109F815EACBC8F3F2636AA956CD1D1780390500D4BDF2B5B0312BF5A0F0EA74D7946DD52B7EA21382C5A9F90F1E1CC07D4A091F3A1C8AB2BA10D521C61571819B4BA15F3FBA841CAA4652122F1BCA639FBF15299F6F69CE9B6E19608729ECD5DC9E17068025FB59D983E7973F6CA27B87F69DA27D1D1C63C4B78D447CD4C8CC0BEA538DA5478465A0FCDEFAA8773162968F273C6BBC1F0CD67B95300F7CA1EEA9DEDB3707759BCA912FACAF02D1F3C37BF73639E3B2E;
80508101C8E444128C5D5C797F4B846EA02B53F56CDF31A8AD546C6E3662888BD3F3D6D980684854D93883DCD2DA3637A8E6AA5618779BD9CED347D5204EC4D4FC6B961D1F458136882D9CA82D95A702EC2D9E20C44B8EAD4590A8E745C994A2D5130890744398BF8284D063F74280D6544757DDDA24B32DFAD3B82E0E9AA0FE463251B9E52935F8AD85469797AA68BCC87EFC14C1CAB260D6E49E31E18B8FEF37129C20DBC1FFE7F27827CB779508BA3018B64EE105324FBF0A83782762097E90F90F4EBFD19F963AA49A88FE;
//expect:959727571EE31D59A2F504A90B38B0103F350BAD27100844381C4B77609635789000
805001023CCB08DB745EAC12A29DDB009E8E8F8C49E8B8B23930D2CAF722BC0D6B52C85594130F247D9807E86C59577D5CB8E9F4ADE541931BFF0E1CED7CFF536E;

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</code>