SHA256withRSA生成公鑰，私鑰

 

package com.fh.util;

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;


public class SHA256withRSAUtil {
	public static void main(String[] args) {
		Map<String, Object> keyPair = generateKeyPair(2048);
		System.out.println(keyPair);
		
	}
	
	
	/**
	 * 生成公鑰，私鑰
	 * 
	 * @param keySize
	 *            the size of key : 1024, 2048
	 * @return Map
	 */
	public static Map<String, Object> generateKeyPair(int keySize) {
		Map<String, Object> rtn = new HashMap<String, Object>();

		try {
			KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
			keyPairGenerator.initialize(keySize);
			KeyPair keyPair = keyPairGenerator.generateKeyPair();
			byte[] publicKey = keyPair.getPublic().getEncoded();
			byte[] privateKey = keyPair.getPrivate().getEncoded();

			String publicStr = base64ToStr(publicKey);
			System.out.println("公鑰字符串----------------\n" + publicStr);
			String privateStr = base64ToStr(privateKey);
			System.out.println("私鑰字符串----------------\n" + privateStr);
			
			rtn.put("PUBLICK_KEY", publicKey);
			rtn.put("PRIVATE_KEY", privateKey);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return rtn;
	}
	public static String base64ToStr(byte[] b) {
		return javax.xml.bind.DatatypeConverter.printBase64Binary(b);
	}
	
	/**
     * 生成DESede算法祕鑰的二進制數組
     * @param keyLen 祕鑰長度，支持：56、64兩種長度
     * @return 祕鑰數組
     */
    public static byte[] generateKey(int keyLen) {
        try {
            KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");
            keyGenerator.init(keyLen);
            SecretKey secretKey = keyGenerator.generateKey();
            return secretKey.getEncoded();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}