...
| Code Block | ||
|---|---|---|
| ||
import java.security.SecureRandom;
import java.security.NoSuchAlgorithmException;
// ...
public static void main (String args[]) {
try {
SecureRandom number = SecureRandom.getInstance("SHA1PRNG");
// Generate 20 integers 0..20
for (int i = 0; i < 20; i++) {
System.out.println(number.nextInt(21));
}
} catch (NoSuchAlgorithmException nsae) {
// Forward to handler
}
}
|
Exceptions
| Wiki Markup |
|---|
*MSC02-EX0:* Using the default constructor for {{java.util.Random}} applies a seed value that is "very likely to be distinct from any other invocation of this constructor" |
\[[API |
2006|AA. References#API 06]\] and may improve security marginally. As a result, it may be used only for noncritical applications operating on nonsensitive data. Java's default seed uses the system's time in milliseconds. When used, explicit documentation of this exception is required. |
| Code Block | ||
|---|---|---|
| ||
import java.util.Random;
// ...
Random number = new Random(); // only used for demo purposes
int n;
//...
for (int i = 0; i < 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);
}
|
...
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="31e2698c2ec666bc-6d5fe6ba-4c684686-a6ce8b31-9364831193812264d53edeb3"><ac:plain-text-body><![CDATA[ | [[API 2006 | https://www.securecoding.cert.org/confluence/display/java/AA.+Java+References#AA.JavaReferences-API06AA. References#API 06]] | [Class | http://java.sun.com/javase/6/docs/api/java/util/Random.html] | ]]></ac:plain-text-body></ac:structured-macro> |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="f4a2b5c63b9b1358-568c2b28-453f4cb0-890d85d2-26b0005c0ff9f288f282a6c7"><ac:plain-text-body><![CDATA[ | [[API 2006 | https://www.securecoding.cert.org/confluence/display/java/AA.+Java+References#AA.JavaReferences-API06AA. References#API 06]] | [Class | http://java.sun.com/javase/6/docs/api/java/security/SecureRandom.html] | ]]></ac:plain-text-body></ac:structured-macro> |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="d4745dc4fad57836-b55b3f1f-4d564548-9a939049-6a828506c3f5d59f07537359"><ac:plain-text-body><![CDATA[ | [[Find Bugs FindBugs 2008 | https://www.securecoding.cert.org/confluence/display/java/AA.+Java+References#AA.JavaReferences-FindBugs08AA. References#FindBugs 08]] | BC. Random objects created and used only once | ]]></ac:plain-text-body></ac:structured-macro> | |
<ac:structured-macro ac:name="unmigrated-wiki-markup" ac:schema-version="1" ac:macro-id="285bc1cb41c559e8-4a1256c8-42f84f21-b35e861d-5790e76787701f37a02c6416"><ac:plain-text-body><![CDATA[ | [[Monsch 2006 | AA. References#Monsch 06]] |
| ]]></ac:plain-text-body></ac:structured-macro> |
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