在Java中是否有任何方法可以生成一个字符串的MD5哈希?
当前回答
没必要把事情搞得太复杂。 DigestUtils工作得很好,使您在使用md5散列时感到舒适。
DigestUtils.md5Hex(_hash);
or
DigestUtils.md5(_hash);
您可以使用任何其他加密方法,如sha或md。
其他回答
没必要把事情搞得太复杂。 DigestUtils工作得很好,使您在使用md5散列时感到舒适。
DigestUtils.md5Hex(_hash);
or
DigestUtils.md5(_hash);
您可以使用任何其他加密方法,如sha或md。
找到了这个解决方案,在从MD5哈希中获得String表示形式方面要干净得多。
import java.security.*;
import java.math.*;
public class MD5 {
public static void main(String args[]) throws Exception{
String s="This is a test";
MessageDigest m=MessageDigest.getInstance("MD5");
m.update(s.getBytes(),0,s.length());
System.out.println("MD5: "+new BigInteger(1,m.digest()).toString(16));
}
}
代码是从这里提取出来的。
是我做的…似乎还行-我相信有人会指出错误…
public final class MD5 {
public enum SaltOption {
BEFORE, AFTER, BOTH, NONE;
}
private static final String ALG = "MD5";
//For conversion to 2-char hex
private static final char[] digits = {
'0' , '1' , '2' , '3' , '4' , '5' ,
'6' , '7' , '8' , '9' , 'a' , 'b' ,
'c' , 'd' , 'e' , 'f' , 'g' , 'h' ,
'i' , 'j' , 'k' , 'l' , 'm' , 'n' ,
'o' , 'p' , 'q' , 'r' , 's' , 't' ,
'u' , 'v' , 'w' , 'x' , 'y' , 'z'
};
private SaltOption opt;
/**
* Added the SaltOption constructor since everybody
* has their own standards when it comes to salting
* hashes.
*
* This gives the developer the option...
*
* @param option The salt option to use, BEFORE, AFTER, BOTH or NONE.
*/
public MD5(final SaltOption option) {
//TODO: Add Char Encoding options too... I was too lazy!
this.opt = option;
}
/**
*
* Returns the salted MD5 checksum of the text passed in as an argument.
*
* If the salt is an empty byte array - no salt is applied.
*
* @param txt The text to run through the MD5 algorithm.
* @param salt The salt value in bytes.
* @return The salted MD5 checksum as a <code>byte[]</code>
* @throws NoSuchAlgorithmException
*/
private byte[] createChecksum(final String txt, final byte[] salt) throws NoSuchAlgorithmException {
final MessageDigest complete = MessageDigest.getInstance(ALG);
if(opt.equals(SaltOption.BEFORE) || opt.equals(SaltOption.BOTH)) {
complete.update(salt);
}
complete.update(txt.getBytes());
if(opt.equals(SaltOption.AFTER) || opt.equals(SaltOption.BOTH)) {
complete.update(salt);
}
return complete.digest();
}
/**
*
* Returns the salted MD5 checksum of the file passed in as an argument.
*
* If the salt is an empty byte array - no salt is applied.
*
* @param fle The file to run through the MD5 algorithm.
* @param salt The salt value in bytes.
* @return The salted MD5 checksum as a <code>byte[]</code>
* @throws IOException
* @throws NoSuchAlgorithmException
*/
private byte[] createChecksum(final File fle, final byte[] salt)
throws IOException, NoSuchAlgorithmException {
final byte[] buffer = new byte[1024];
final MessageDigest complete = MessageDigest.getInstance(ALG);
if(opt.equals(SaltOption.BEFORE) || opt.equals(SaltOption.BOTH)) {
complete.update(salt);
}
int numRead;
InputStream fis = null;
try {
fis = new FileInputStream(fle);
do {
numRead = fis.read(buffer);
if (numRead > 0) {
complete.update(buffer, 0, numRead);
}
} while (numRead != -1);
} finally {
if (fis != null) {
fis.close();
}
}
if(opt.equals(SaltOption.AFTER) || opt.equals(SaltOption.BOTH)) {
complete.update(salt);
}
return complete.digest();
}
/**
*
* Efficiently converts a byte array to its 2 char per byte hex equivalent.
*
* This was adapted from JDK code in the Integer class, I just didn't like
* having to use substrings once I got the result...
*
* @param b The byte array to convert
* @return The converted String, 2 chars per byte...
*/
private String convertToHex(final byte[] b) {
int x;
int charPos;
int radix;
int mask;
final char[] buf = new char[32];
final char[] tmp = new char[3];
final StringBuilder md5 = new StringBuilder();
for (int i = 0; i < b.length; i++) {
x = (b[i] & 0xFF) | 0x100;
charPos = 32;
radix = 1 << 4;
mask = radix - 1;
do {
buf[--charPos] = digits[x & mask];
x >>>= 4;
} while (x != 0);
System.arraycopy(buf, charPos, tmp, 0, (32 - charPos));
md5.append(Arrays.copyOfRange(tmp, 1, 3));
}
return md5.toString();
}
/**
*
* Returns the salted MD5 checksum of the file passed in as an argument.
*
* @param fle The file you want want to run through the MD5 algorithm.
* @param salt The salt value in bytes
* @return The salted MD5 checksum as a 2 char per byte HEX <code>String</code>
* @throws NoSuchAlgorithmException
* @throws IOException
*/
public String getMD5Checksum(final File fle, final byte[] salt)
throws NoSuchAlgorithmException, IOException {
return convertToHex(createChecksum(fle, salt));
}
/**
*
* Returns the MD5 checksum of the file passed in as an argument.
*
* @param fle The file you want want to run through the MD5 algorithm.
* @return The MD5 checksum as a 2 char per byte HEX <code>String</code>
* @throws NoSuchAlgorithmException
* @throws IOException
*/
public String getMD5Checksum(final File fle)
throws NoSuchAlgorithmException, IOException {
return convertToHex(createChecksum(fle, new byte[0]));
}
/**
*
* Returns the salted MD5 checksum of the text passed in as an argument.
*
* @param txt The text you want want to run through the MD5 algorithm.
* @param salt The salt value in bytes.
* @return The salted MD5 checksum as a 2 char per byte HEX <code>String</code>
* @throws NoSuchAlgorithmException
* @throws IOException
*/
public String getMD5Checksum(final String txt, final byte[] salt)
throws NoSuchAlgorithmException {
return convertToHex(createChecksum(txt, salt));
}
/**
*
* Returns the MD5 checksum of the text passed in as an argument.
*
* @param txt The text you want want to run through the MD5 algorithm.
* @return The MD5 checksum as a 2 char per byte HEX <code>String</code>
* @throws NoSuchAlgorithmException
* @throws IOException
*/
public String getMD5Checksum(final String txt)
throws NoSuchAlgorithmException {
return convertToHex(createChecksum(txt, new byte[0]));
}
}
Bombe的答案是正确的,但请注意,除非你绝对必须使用MD5(例如,为了互操作性而被迫使用),否则更好的选择是SHA1,因为MD5长期使用有缺点。
我应该补充一点,SHA1也有理论上的漏洞,但没有那么严重。目前的哈希技术水平是,有许多候选替换哈希函数,但还没有一个成为取代SHA1的标准最佳实践。因此,根据您的需要,建议您使您的哈希算法可配置,以便将来可以替换它。
不像PHP,你可以通过调用MD5函数ie MD5 ($text)来对文本进行MD5哈希,在Java中它有点复杂。我通常通过调用一个返回md5哈希文本的函数来实现它。 首先在你的主类中创建一个名为md5hashing的函数,如下所示。
public static String md5hashing(String text)
{ String hashtext = null;
try
{
String plaintext = text;
MessageDigest m = MessageDigest.getInstance("MD5");
m.reset();
m.update(plaintext.getBytes());
byte[] digest = m.digest();
BigInteger bigInt = new BigInteger(1,digest);
hashtext = bigInt.toString(16);
// Now we need to zero pad it if you actually want the full 32 chars.
while(hashtext.length() < 32 ){
hashtext = "0"+hashtext;
}
} catch (Exception e1)
{
// TODO: handle exception
JOptionPane.showMessageDialog(null,e1.getClass().getName() + ": " + e1.getMessage());
}
return hashtext;
}
现在,在需要时调用该函数,如下所示。
String text = textFieldName.getText();
String pass = md5hashing(text);
在这里,您可以看到hashtext被附加了一个0,以使其与PHP中的md5散列匹配。
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