1 | package gov.hhs.fha.nhinc.util.hash;
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2 |
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3 | import java.io.UnsupportedEncodingException;
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4 | import java.security.MessageDigest;
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5 | import java.security.NoSuchAlgorithmException;
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6 |
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7 | /**
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8 | * This class is used to compute the SHA1 hash code of a string.
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9 | *
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10 | * @author Les Westberg
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11 | */
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12 | public class SHA1HashCode
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13 | {
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14 |
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15 | /**
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16 | * This method takes a byte array and converts it to a String HEX representation
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17 | * of the byte array.
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18 | *
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19 | * @param data The byte array to be converted.
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20 | * @return The HEX string representation of the byte array.
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21 | */
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22 | private static String convertToHex(byte[] data)
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23 | {
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24 | StringBuffer buf = new StringBuffer();
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25 | for (int i = 0; i < data.length; i++)
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26 | {
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27 | int halfbyte = (data[i] >>> 4) & 0x0F;
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28 | int two_halfs = 0;
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29 | do
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30 | {
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31 | if ((0 <= halfbyte) && (halfbyte <= 9))
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32 | {
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33 | buf.append((char) ('0' + halfbyte));
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34 | } else
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35 | {
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36 | buf.append((char) ('a' + (halfbyte - 10)));
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37 | }
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38 | halfbyte = data[i] & 0x0F;
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39 | } while (two_halfs++ < 1);
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40 | }
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41 | return buf.toString();
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42 | }
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43 |
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44 |
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45 | /**
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46 | * This method calculates the SHA1 hash code for the given string.
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47 | *
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48 | * @param text The string that is being used to compute the SHA-1 hash code.
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49 | * @return The SHA-1 has code based on the given string.
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50 | * @throws java.security.NoSuchAlgorithmException
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51 | * @throws java.io.UnsupportedEncodingException
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52 | */
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53 | public static String calculateSHA1(String text)
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54 | throws NoSuchAlgorithmException, UnsupportedEncodingException
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55 | {
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56 | if (text != null)
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57 | {
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58 | MessageDigest md;
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59 | md = MessageDigest.getInstance("SHA-1");
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60 | byte[] sha1hash = new byte[40];
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61 | md.update(text.getBytes("iso-8859-1"), 0, text.length());
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62 | sha1hash = md.digest();
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63 | return convertToHex(sha1hash);
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64 | }
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65 | else
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66 | {
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67 | return "";
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68 | }
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69 | }
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70 | }
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