字節數組的計算SHA-1

Question

我正在尋找一種以Java字節數組作爲消息獲取SHA-1校驗和的方法。

我應該使用第三方工具還是有內置JVM的幫助？

Answer 1

什麼：

import java.security.MessageDigest; 
import java.security.NoSuchAlgorithmException; 
import java.util.Formatter; 

public static String SHAsum(byte[] convertme) throws NoSuchAlgorithmException{ 
    MessageDigest md = MessageDigest.getInstance("SHA-1"); 
    return byteArray2Hex(md.digest(convertme)); 
} 

private static String byteArray2Hex(final byte[] hash) { 
    Formatter formatter = new Formatter(); 
    for (byte b : hash) { 
     formatter.format("%02x", b); 
    } 
    return formatter.toString(); 
} 

Answer 2

這一小段代碼，我們用它來轉換爲SHA-1，但需要String代替Byte[]看到這個javadoc進一步信息

 import java.io.UnsupportedEncodingException; 
     import java.security.MessageDigest; 
     import java.security.NoSuchAlgorithmException; 

     public class DoSHA1 { 

      private static String convToHex(byte[] data) { 
       StringBuilder buf = new StringBuilder(); 
       for (int i = 0; i < data.length; i++) { 
        int halfbyte = (data[i] >>> 4) & 0x0F; 
        int two_halfs = 0; 
        do { 
         if ((0 <= halfbyte) && (halfbyte <= 9)) 
          buf.append((char) ('0' + halfbyte)); 
         else 
          buf.append((char) ('a' + (halfbyte - 10))); 
         halfbyte = data[i] & 0x0F; 
        } while(two_halfs++ < 1); 
       } 
       return buf.toString(); 
      } 

      public static String SHA1(String text) throws NoSuchAlgorithmException, 
UnsupportedEncodingException { 
      MessageDigest md = MessageDigest.getInstance("SHA-1"); 
      byte[] sha1hash = new byte[40]; 
      md.update(text.getBytes("iso-8859-1"), 0, text.length()); 
      sha1hash = md.digest(); 
      return convToHex(sha1hash); 
      } 
     } 

Answer 3

你可以自己做，或者你可以依靠已經證明可以工作的庫，如Commons Codec。該DigestUtils類有幾個方法來計算散列..

Answer 4

從CommonCodec DigestUtils執行的摘要計算後的十六進制丁文如圖之前：

MessageDigest md = MessageDigest.getInstance("SHA-1"); 
return byteArray2Hex(md.digest(convertme)); 

應http://commons.apache.org/codec/apidocs/src-html/org/apache/commons/codec/binary/Hex.html#line.129：

private static final char[] DIGITS_LOWER = 
    {'0', '1', '2', '3', '4', '5', '6', '7', 
    '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; 

private static final char[] DIGITS_UPPER = 
    {'0', '1', '2', '3', '4', '5', '6', '7', 
    '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'}; 

protected static char[] encodeHex(byte[] data, char[] toDigits) { 
    int l = data.length; 
    char[] out = new char[l << 1]; 
    // two characters form the hex value. 
    for (int i = 0, j = 0; i < l; i++) { 
     out[j++] = toDigits[(0xF0 & data[i]) >>> 4]; 
     out[j++] = toDigits[0x0F & data[i]]; 
    } 
    return out; 
} 

protected static int toDigit(char ch, int index) throws DecoderException { 
    int digit = Character.digit(ch, 16); 
    if (digit == -1) { 
     throw new DecoderException(
        "Illegal hexadecimal character " 
      + ch + " at index " + index); 
    } 
    return digit; 
} 

public static String exampleSha1(String convertme){ 
    MessageDigest md = MessageDigest.getInstance("SHA-1"); 
    byte[] encodeHex = md.digest(convertme)); 
    return new String(encodeHex); 
} 

Answer 5

..另一種選擇是使用彈簧：

<bean id="passwordEncoder" class="org.springframework.security.authentication.encoding.ShaPasswordEncoder"> 
    <constructor-arg value="256"/> 
</bean> 

閱讀更多here

HTH

Answer 6

我只是用這個來計算DEX文件內的哈希值總和，它與被保存在DEX文件中的值進行比較。

我知道這個代碼沒有很好的風格，但它更多的PoC，只需要一些對時間非常關鍵的研究。可能有人可以使用它！

class CheckDex{ 
public boolean checkSHA1(File f) throws IOException, NoSuchAlgorithmException{ 
    RandomAccessFile raf = new RandomAccessFile(f, "r"); 
    byte[] sig = new byte[20]; 
    raf.seek(0xC); 
    for(int i = 0; i < 20; i++){ 
     sig[i] = (byte) raf.readUnsignedByte(); 
    } 

    MessageDigest md = MessageDigest.getInstance("SHA-1"); 

    byte[] code = new byte[(int) (raf.length()-32)]; 
    for(int i = 0; i < code.length; i++){ 
     code[i] = (byte) raf.readUnsignedByte(); 
    } 
    byte[] comsig = md.digest(code); 

    raf.close(); 
    return Arrays.equals(sig,comsig); 
} 
} 

Answer 7

如何使用本：

公共類sha1Calculate {

public static void main(String[] args)throws Exception 
    { 
     File file = new File("D:\\Android Links.txt"); 
     String outputTxt= ""; 
     String hashcode = null; 

     try { 

      FileInputStream input = new FileInputStream(file); 

      ByteArrayOutputStream output = new ByteArrayOutputStream(); 
      byte [] buffer = new byte [65536]; 
      int l; 

      while ((l = input.read (buffer)) > 0) 
       output.write (buffer, 0, l); 

      input.close(); 
      output.close(); 

      byte [] data = output.toByteArray(); 


       MessageDigest digest = MessageDigest.getInstance("SHA-1"); 

      byte[] bytes = data; 

      digest.update(bytes, 0, bytes.length); 
      bytes = digest.digest(); 

      StringBuilder sb = new StringBuilder(); 

      for(byte b : bytes) 
      { 
       sb.append(String.format("%02X", b)); 
      } 

       System.out.println("Digest(in hex format):: " + sb.toString()); 


     }catch (FileNotFoundException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } catch (NoSuchAlgorithmException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 

    } 

}