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<TITLE>Generating a Secure Random Number
(Java Developers Almanac Example)
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<h3>
e196.
Generating a Secure Random Number</h3>
This example creates a random number using a secure random number generator:
See also <a href="../java.security/ListSecureRnd.html" class="eglink"><font size="-1"><b>e195</b> Listing All Available Secure Random Number Generators</font></a>.
<pre>
try {
// Create a secure random number generator
SecureRandom sr = SecureRandom.getInstance(<font color="#0066ff"><i>"SHA1PRNG"</i></font>);
// Get 1024 random bits
byte[] bytes = new byte[<font color="#0066ff"><i>1024/8</i></font>];
sr.nextBytes(bytes);
// Create two secure number generators with the same seed
int seedByteCount = <font color="#0066ff"><i>10</i></font>;
byte[] seed = sr.generateSeed(seedByteCount);
sr = SecureRandom.getInstance(<font color="#0066ff"><i>"SHA1PRNG"</i></font>);
sr.setSeed(seed);
SecureRandom sr2 = SecureRandom.getInstance(<font color="#0066ff"><i>"SHA1PRNG"</i></font>);
sr2.setSeed(seed);
} catch (NoSuchAlgorithmException e) {
}
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Related Examples
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e193. <a class="eglink" href="EnableDebug.html?l=rel">
Printing Security System Trace Messages
</a>
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e194. <a class="eglink" href="ListServices.html?l=rel">
Listing All Available Cryptographic Services
</a>
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e195. <a class="eglink" href="ListSecureRnd.html?l=rel">
Listing All Available Secure Random Number Generators
</a>
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See also:
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Key%20Store">
Key Store
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Message%20Digests">
Message Digests
</a>
<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Permissions">
Permissions
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<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Policy%20Files">
Policy Files
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<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Public%20and%20Private%20Keys">
Public and Private Keys
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<a class="eglink" href="/egs/java.security/pkg.html?l=rel#Signatures">
Signatures
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