The Java Developers Almanac 1.4


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Home > List of Packages > java.security  [30 examples]

e196. Generating a Secure Random Number

This example creates a random number using a secure random number generator: See also e195 Listing All Available Secure Random Number Generators.
    try {
        // Create a secure random number generator
        SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
    
        // Get 1024 random bits
        byte[] bytes = new byte[1024/8];
        sr.nextBytes(bytes);
    
    
        // Create two secure number generators with the same seed
        int seedByteCount = 10;
        byte[] seed = sr.generateSeed(seedByteCount);
    
        sr = SecureRandom.getInstance("SHA1PRNG");
        sr.setSeed(seed);
        SecureRandom sr2 = SecureRandom.getInstance("SHA1PRNG");
        sr2.setSeed(seed);
    } catch (NoSuchAlgorithmException e) {
    }

 Related Examples
e193. Printing Security System Trace Messages
e194. Listing All Available Cryptographic Services
e195. Listing All Available Secure Random Number Generators

See also: Key Store    Message Digests    Permissions    Policy Files    Public and Private Keys    Signatures   


© 2002 Addison-Wesley.