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Code Block

bgColor	#FFCCCC

import java.util.Random;
// ...

Random number = new Random(123L);
//...
for (int i=0; i&lti<20;20; i++) {
  // generate another random integer in the range [0, 20]
  int n = number.nextInt(21);
  System.out.println(n);
}

...

Code Block

bgColor	#ccccff

import java.security.SecureRandom;
import java.security.NoSuchAlgorithmException;
// ...

public static void main (String args[]) {
   try {
     SecureRandom number = SecureRandom.getInstance(&quot;SHA1PRNG&quot;"SHA1PRNG");
     // Generate 20 integers 0..20
     for (int i = 0; i &lt;< 20; i++) {
       System.out.println(number.nextInt(21));
     }
   }
   catch (NoSuchAlgorithmException nsae) { 
     // Forward to handler
   }
}

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Code Block

bgColor	#ccccff

import java.util.Random;
// ...

Random number = new Random();
int n;
//...
for (int i=0; i&lt;20i<20; i++) {
  // Re-seed generator
  number = new Random();
  // Generate another random integer in the range [0, 20]
  n = number.nextInt(21);
  System.out.println(n);
}

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Wiki Markup

\[[API 06|https://www.securecoding.cert.org/confluence/display/java/AA.+Java+References#AA.JavaReferences-API06]\]&amp;nbsp;[Class Random|http://java.sun.com/javase/6/docs/api/java/util/Random.html]
\[[API 06|https://www.securecoding.cert.org/confluence/display/java/AA.+Java+References#AA.JavaReferences-API06]\] [Class SecureRandom|http://java.sun.com/javase/6/docs/api/java/security/SecureRandom.html]
\[[Find Bugs 08|https://www.securecoding.cert.org/confluence/display/java/AA.+Java+References#AA.JavaReferences-FindBugs08]\] BC: Random objects created and used only once
\[[Monsch 06|AA. Java References#Monsch 06]\]
\[[MITRE 09|AA. Java References#MITRE 09]\] [CWE ID 330|http://cwe.mitre.org/data/definitions/330.html] &quot;"Use of Insufficiently Random Values&quot;", [CWE ID 327 |http://cwe.mitre.org/data/definitions/327.html], &quot;"Use of a Broken or Risky Cryptographic Algorithm,&quot;" [CWE ID 330|http://cwe.mitre.org/data/definitions/330.html], &quot;"Use of Insufficiently Random Values&quot;", [CWE ID 333| http://cwe.mitre.org/data/definitions/333.html] &quot;"Failure to Handle Insufficient Entropy in TRNG&quot;", [CWE ID 332|http://cwe.mitre.org/data/definitions/332.html] &quot;"Insufficient Entropy in PRNG&quot;", [CWE ID 337|http://cwe.mitre.org/data/definitions/337.html] &quot;"Predictable Seed in PRNG&quot;", [CWE ID 336|http://cwe.mitre.org/data/definitions/336.html] &quot;"Same Seed in PRNG&quot;"

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MSC07MSC09-J. Do not assume infinite heap space      use insecure or weak cryptographic algorithms 49. Miscellaneous (MSC)       MSC31-J. Never hardcode sensitive information

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