MessageDigest メモ

gistfile1.java

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;

public class MainActivity extends Activity {

    private final String TAG = getClass().getSimpleName();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        String message = "Android";

        /* 
         * MD5     : 128bit
         * SHA-1   : 160bit
         * SHA-224 : 224bit
         * SHA-256 : 256bit
         * SHA-384 : 384bit
         * SHA-512 : 512bit
         * メモ : SHA-224〜SHA-512を総称してSHA-2と呼ぶ
         *       SHAはSHA-1と同義
         *       SHA-224は非サポート
         */
        String[] algorithm = {
                "MD5", "SHA", "SHA-1", "SHA-224", "SHA-256", "SHA-384", "SHA-512"
        };

        for (int i = 0; i < algorithm.length; i++) {
            try {
                StringBuffer digest = new StringBuffer();

                MessageDigest messageDigest = MessageDigest.getInstance(algorithm[i]);
                messageDigest.update(message.getBytes());
                byte digestByteArray[] = messageDigest.digest();

                for (int j = 0; j < digestByteArray.length; j++) {
                    digest.append(Integer.toHexString(0xFF & digestByteArray[j]));
                }

                Log.e(TAG, "Digest(" + algorithm[i] + ") : " + digest);
            } catch (NoSuchAlgorithmException e) {
                Log.e(TAG, "NoSuchAlgorithmException : " + e);
            }
        }
    }

}