RSA双向加解密（公钥加密-私钥解密；私钥加密-公钥解密）

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        非对称加密算法中，提供一个公钥一个私钥。一般情况下，采用公钥加密、私钥解密的方式。

        假设有这样一个场景：服务A与服务B需要通信，通信内容为了安全需要进行加密传输，并且服务A与服务B不能互相持有对方的钥匙。

        我首先想到的是能否利用RSA实现双向的加解密，查阅了资料后做了一个简单的实现，下面贴出实现原理及代码：

public class RsaEncryptUtil{ public static final String PUBLIC_KEY="publicKey"; public static final String PRIVATE_KEY="privateKey"; private static final String KEY_STORE = "JKS"; private static final int MAX_ENCRYPT_LENGTH = 117; private static final int MAX_DECRYPT_LENGTH = 128; / * 随机生成RAS公钥与私钥字符串，直接返回 */ public static Map<String, String> getKeys() { KeyPairGenerator keyPairGen; try { keyPairGen = KeyPairGenerator.getInstance("RSA"); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); throw new RSAException("RSA获取钥匙对失败", e); } // 初始化密钥对生成器，密钥大小为96-1024位 keyPairGen.initialize(1024,new SecureRandom()); // 生成一个密钥对，保存在keyPair中 KeyPair keyPair = keyPairGen.generateKeyPair(); Map<String,String> keyMap = new HashMap<>(); keyMap.put(PUBLIC_KEY, RSACryptUtil.base64ToStr(keyPair.getPublic().getEncoded())); keyMap.put(PRIVATE_KEY, RSACryptUtil.base64ToStr(keyPair.getPrivate().getEncoded())); return keyMap; } / * 获得KeyStore * * @param keyStorePath * @param password */ private static KeyStore getKeyStore(String keyStorePath, String password) throws Exception { FileInputStream is = new FileInputStream(keyStorePath); KeyStore ks = KeyStore.getInstance(KEY_STORE); ks.load(is, password.toCharArray()); is.close(); return ks; } / * 由KeyStore获得私钥 * * @param keyStorePath KeyStore路径 * @param alias 别名 * @param storePass KeyStore访问密码 * @param keyPass 私钥的钥匙密码 */ private static PrivateKey loadPrivateKey(String keyStorePath, String alias, String storePass, String keyPass) throws Exception { KeyStore ks = getKeyStore(keyStorePath, storePass); PrivateKey key = (PrivateKey) ks.getKey(alias, keyPass.toCharArray()); return key; } / * 由Certificate获得公钥 * * @param keyStorePath KeyStore路径 * @param alias 别名 * @param storePass KeyStore访问密码 */ private static PublicKey loadPublicKey(String keyStorePath, String alias, String storePass) throws Exception { KeyStore ks = getKeyStore(keyStorePath, storePass); PublicKey key = ks.getCertificate(alias).getPublicKey(); return key; } / * 公钥加密 * * @param publicKey 公钥 * @param content 明文数据 */ public static String encryptByPublic(String publicKey, String content){ if (StringUtils.isEmpty(publicKey)) { throw new RSAException("加密公钥为空, 请设置"); } if(StringUtils.isEmpty(content)){ throw new RSAException("加密明文为空, 请设置"); } Cipher cipher; StringBuilder result = new StringBuilder(); try { // 使用默认RSA cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, RSACryptUtil.loadPublicKey(publicKey)); byte[] bytes = content.getBytes(); for (int i = 0; i < bytes.length; i += MAX_ENCRYPT_LENGTH) { byte[] subarray = ArrayUtils.subarray(bytes, i, i + MAX_ENCRYPT_LENGTH); if(subarray != null && subarray.length > 0){ byte[] doFinal = cipher.doFinal(subarray); result.append(RSACryptUtil.base64ToStr(doFinal)); } } return result.toString(); } catch (NoSuchAlgorithmException e) { throw new RSAException("无此加密算法",e); } catch (NoSuchPaddingException e) { e.printStackTrace(); return null; } catch (InvalidKeyException e) { throw new RSAException("加密公钥非法,请检查",e); } catch (IllegalBlockSizeException e) { throw new RSAException("明文长度非法",e); } catch (BadPaddingException e) { throw new RSAException("明文数据已损坏",e); } catch (Exception e) { throw new RSAException("未知错误",e); } } / * 私钥解密 * * @param privateKey 私钥 * @param content 密文数据 */ public static String decryptByPrivate(String privateKey, String content){ if (StringUtils.isEmpty(privateKey)) { throw new RSAException("解密私钥为空, 请设置"); } if(StringUtils.isEmpty(content)){ throw new RSAException("解密密文为空, 请设置"); } if(content.length() < 4){ throw new RSAException("解密密文有误：" + content); } Cipher cipher; StringBuilder result = new StringBuilder(); try { // 使用默认RSA cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, RSACryptUtil.loadPrivateKey(privateKey)); byte[] bytes = RSACryptUtil.strToBase64(content); for (int i = 0; i < bytes.length; i += MAX_DECRYPT_LENGTH) { byte[] subarray = ArrayUtils.subarray(bytes, i, i + MAX_DECRYPT_LENGTH); if(subarray != null && subarray.length > 0){ byte[] doFinal = cipher.doFinal(subarray); result.append(new String(doFinal)); } } return result.toString(); } catch (NoSuchAlgorithmException e) { throw new RSAException("无此解密算法",e); } catch (NoSuchPaddingException e) { e.printStackTrace(); return null; } catch (InvalidKeyException e) { throw new RSAException("解密私钥非法,请检查"); } catch (IllegalBlockSizeException e) { throw new RSAException("密文长度非法",e); } catch (BadPaddingException e) { throw new RSAException("密文数据已损坏",e); } catch (Exception e) { e.printStackTrace(); throw new RSAException("未知错误",e); } } / * 私钥加密 * * @param privateKey 私钥 * @param content 明文数据 */ public static String encryptByPrivate(String privateKey,String content){ if (StringUtils.isEmpty(privateKey)) { throw new RSAException("加密私钥为空, 请设置"); } if(StringUtils.isEmpty(content)){ throw new RSAException("加密明文为空, 请设置"); } Cipher cipher; StringBuilder result = new StringBuilder(); try { // 使用默认RSA cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, RSACryptUtil.loadPrivateKey(privateKey)); byte[] bytes = content.getBytes(); for (int i = 0; i < bytes.length; i += MAX_ENCRYPT_LENGTH) { byte[] subarray = ArrayUtils.subarray(bytes, i, i + MAX_ENCRYPT_LENGTH); if(subarray != null && subarray.length > 0){ byte[] doFinal = cipher.doFinal(subarray); result.append(RSACryptUtil.base64ToStr(doFinal)); } } return result.toString(); }catch (NoSuchAlgorithmException e) { throw new RSAException("无此加密算法",e); } catch (NoSuchPaddingException e) { e.printStackTrace(); return null; } catch (InvalidKeyException e) { throw new RSAException("加密私钥非法,请检查",e); } catch (IllegalBlockSizeException e) { throw new RSAException("明文长度非法",e); } catch (BadPaddingException e) { throw new RSAException("明文数据已损坏",e); } } / * 公钥解密 * * @param publicKey 公钥 * @param content 密文数据 */ public static String decryptByPublic(String publicKey, String content){ if (StringUtils.isEmpty(publicKey)) { throw new RSAException("解密公钥为空, 请设置"); } if(StringUtils.isEmpty(content)){ throw new RSAException("解密密文为空, 请设置"); } if(content.length() < 4){ throw new RSAException("解密密文有误：" + content); } Cipher cipher; StringBuilder result = new StringBuilder(); try { // 使用默认RSA cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, RSACryptUtil.loadPublicKey(publicKey)); byte[] bytes = RSACryptUtil.strToBase64(content); for (int i = 0; i < bytes.length; i += MAX_DECRYPT_LENGTH) { byte[] subarray = ArrayUtils.subarray(bytes, i, i + MAX_DECRYPT_LENGTH); if(subarray != null && subarray.length > 0){ byte[] doFinal = cipher.doFinal(subarray); result.append(new String(doFinal)); } } return result.toString(); }catch (NoSuchAlgorithmException e) { throw new RSAException("无此解密算法",e); } catch (NoSuchPaddingException e) { e.printStackTrace(); return null; } catch (InvalidKeyException e) { throw new RSAException("解密公钥非法,请检查",e); } catch (IllegalBlockSizeException e) { throw new RSAException("密文长度非法",e); } catch (BadPaddingException e) { throw new RSAException("密文数据已损坏",e); } } }