2martens/uni
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[Projekt] Klasse fertiggestellt

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Signed-off-by: Jim Martens <github@2martens.de>
This commit is contained in:
Jim Martens
2015-04-09 16:32:10 +02:00
parent c2c9e63ee7
commit b1e330ae49
1 changed files with 37 additions and 8 deletions
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45
projekt/Useradmin.java
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@ -1,6 +1,8 @@
import java.io.*;
import java.math.BigInteger;
import java.nio.file.*;
import java.nio.charset.*;
import java.security.*;
import java.util.List;
class Useradmin {
@ -29,9 +31,9 @@ class Useradmin {
}
public void addUser(String username, char[] password) {
char[] hashedPW = password;
String hashedPWString = String.valueOf(hashedPW);
String format = username + ":" + hashedPWString;
String salt = genSalt();
String hashedPW = generateHash(String.valueOf(password), salt);
String format = username + ":" + hashedPW;
try(PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter("passwords.txt", true)))) {
out.println(format);
System.out.println("User has been created");
@ -41,8 +43,6 @@ class Useradmin {
}
public boolean checkUser(String username, char[] password) {
char[] hashedPW = password;
String hashedPWString = String.valueOf(hashedPW);
boolean result = false;
try {
List<String> passwords = Files.readAllLines(Paths.get("passwords.txt"), StandardCharsets.UTF_8);
@ -50,8 +50,12 @@ class Useradmin {
for (String uidPW : passwords) {
int indexOfColon = uidPW.indexOf(':');
String user = uidPW.substring(0, indexOfColon);
String pw = uidPW.substring(indexOfColon + 1);
if (user.equals(username) && pw.equals(hashedPWString)) {
String pwSalt = uidPW.substring(indexOfColon + 1);
indexOfColon = pwSalt.indexOf(':');
String salt = pwSalt.substring(0, indexOfColon);
String hashedPWString = generateHash(String.valueOf(password), salt);
if (user.equals(username) && pwSalt.equals(hashedPWString)) {
result = true;
}
}
@ -61,4 +65,29 @@ class Useradmin {
}
return result;
}
}
private String generateHash(String str, String salt) {
String hashValue = salt + str;
for (int i = 0; i < 4200; i++) {
hashValue = hash(hashValue);
}
return salt + ":" + hashValue;
}
private String hash(String str) {
try {
byte[] plain = str.getBytes(StandardCharsets.UTF_8);
MessageDigest md = MessageDigest.getInstance("SHA-512");
md.update(plain);
return new BigInteger(1, md.digest()).toString(16);
} catch (NoSuchAlgorithmException e) {
throw new UnsupportedOperationException(e);
}
}
private String genSalt() {
SecureRandom random = new SecureRandom();
return new BigInteger(32, random).toString(32);
}
}