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Generate Passphrases in Java

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[ Code Example - Quick Summary ]

Language: Java

What: Generate cryptographically secure passphrases in Java using <code>SecureRandom</code> for enterprise applications. This implementation follows the Diceware method for maximum security.

Try it: Use our interactive Passphrases generator or integrate this code into your Java application.

Generate cryptographically secure passphrases in Java using SecureRandom for enterprise applications. This implementation follows the Diceware method for maximum security. Looking for other languages? Check our code examples in PHP , JavaScript , Python , C# , C++ , Ruby and Go or use our interactive web generator.

Java Code Example

import java.security.SecureRandom;
import java.util.Arrays;
import java.util.List;

public class PassphraseGenerator {
    private static final List<String> WORDLIST = Arrays.asList(
        "ability", "able", "about", "above", "accept" // ... 7771 more words
    );

    private static final SecureRandom random = new SecureRandom();

    public static String generatePassphrase(int wordCount) {
        StringBuilder passphrase = new StringBuilder();

        for (int i = 0; i < wordCount; i++) {
            if (i > 0) passphrase.append("-");
            int index = random.nextInt(WORDLIST.size());
            passphrase.append(WORDLIST.get(index));
        }

        return passphrase.toString();
    }

    public static void main(String[] args) {
        // Generate 6-word passphrase
        String passphrase = generatePassphrase(6);
        System.out.println(passphrase);
        // Output: "crystal-mountain-thunder-freedom-velocity-brilliant"

        // Calculate entropy
        double entropy = wordCount * Math.log(WORDLIST.size()) / Math.log(2);
        System.out.printf("Entropy: %.1f bits%n", entropy);  // 77.5 bits
    }
}

[EXPLANATION]

Java's SecureRandom class provides cryptographically strong random number generation suitable for security-sensitive applications. The implementation uses a static wordlist and reuses the SecureRandom instance for performance. This approach is thread-safe and suitable for enterprise web applications.

Expected Output

crystal-mountain-thunder-freedom-velocity-brilliant
phoenix-quantum-nebula-cascade-harmony-infinite
cosmos-radiant-jupiter-starlight-eclipse-zenith

Common Use Cases

Spring Boot authentication systems
Enterprise user provisioning
Password reset flows
Java-based password managers
Android app master passwords

Important Notes

SecureRandom is thread-safe but expensive to initialize
Reuse SecureRandom instances for better performance
Load wordlist from resources file in production
Consider using String.join() for cleaner code
For Android, use SecureRandom.getInstanceStrong()

Try Our Interactive Generator

Don't want to write code? Use our free web-based Passphrases generator with instant results.

TRY PASSPHRASES GENERATOR →

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