RSA 加密 解密 加签 验签

1.公钥与私钥码生成

http://web.chacuo.net/netrsakeypair

2.获取公钥

    /**
     * 获取公钥
     * @return
     */
    private PublicKey getPublicKey(){
        byte[] bytesPublic = getBytesBASE64(publicKey);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(bytesPublic);
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            return keyFactory.generatePublic(keySpec);
        } catch (Exception e) {
            log.error("getPublicKey-Exception", e);
            return null;
        }
    }

获取私钥

  /**
     * 获取私钥
     * @return
     */
    private PrivateKey getPrivateKey(){
        byte[] bytesPrivate = getBytesBASE64(privateKey);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(bytesPrivate);
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            return keyFactory.generatePrivate(keySpec);
        } catch (Exception e) {
            log.error("getPrivateKey-Exception", e);
            return null;
        }
    }

base64转码工具类

    /**
     * BASE64 编码的字符串 str 进行解码
     * @param str
     * @return
     */
    private byte[] getBytesBASE64(String str) {
        if (str == null) {
            return null;
        }
        BASE64Decoder decoder = new BASE64Decoder();
        try {
            return decoder.decodeBuffer(str);
        } catch (Exception e) {
            return null;
        }
    }

3.加密数据

    /**
     * 加密数据
     * @param originData
     * @return
     */
    public String encodeData(String originData){
        try {
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE,getPublicKey());
            byte[] bytesEncrypt = cipher.doFinal(originData.getBytes());
            byte[] bytesEncryptBase64 = Base64.getEncoder().encode(bytesEncrypt);
            return new String(bytesEncryptBase64);
        } catch (Exception e) {
            log.error("encodeData-Exception", e);
            return null;
        }
    }

解密数据

    /**
     * 解密数据
     * @param encodeData
     * @return
     */
    public String decodeData(String encodeData){
        try {
            byte[] bytesEncrypt = getBytesBASE64(encodeData);
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE,getPrivateKey());
            byte[] bytesDecrypt = cipher.doFinal(bytesEncrypt);
            return new String(bytesDecrypt);
        } catch (Exception e) {
            log.error("decodeData-Exception", e);
            return null;
        }
    }

4.加签

    /**
     * 加签
     * @param data
     * @return
     */
    public String sign(String data) {
        try {
            PrivateKey privateKey = getPrivateKey();
            Signature signature = Signature.getInstance("Sha1WithRSA");
            signature.initSign(privateKey);
            signature.update(data.getBytes(StandardCharsets.UTF_8));
            byte[] signed = signature.sign();
            return Base64.getEncoder().encodeToString(signed);
        }catch (Exception e){
            log.error("sign-Exception", e);
            return null;
        }
    }

验签

    /**
     * 验签
     * @param data
     * @param sign
     * @return
     */
    public boolean verify(String data, String sign){
        try {
            PublicKey publicKey = getPublicKey();
            Signature signature = Signature.getInstance("Sha1WithRSA");
            signature.initVerify(publicKey);
            signature.update(data.getBytes(StandardCharsets.UTF_8));
            byte[] signby = getBytesBASE64(sign);
            return signature.verify(signby);
        }catch (Exception e){
            log.error("verify-Exception", e);
            return false;
        }
    }

json排序工具类

    /**
     * 生成待签名串
     * @param jsonObject
     * @return
     */
    private String buildSignData(JSONObject jsonObject) {
        StringBuilder content = new StringBuilder();
        // 按照key做首字母升序排列
        List<String> keys = new ArrayList<String>(jsonObject.keySet());
        keys.sort(String.CASE_INSENSITIVE_ORDER);
        for (int i = 0; i < keys.size(); i++) {
            String key = (String) keys.get(i);
            if ("sign".equals(key)) {
                continue;
            }
            String value = jsonObject.getString(key);
            if (StringUtils.isBlank(value)) {
                continue;
            }
            content.append(i == 0 ? "" : "&").append(key).append("=").append(value);
        }
        String signSrc = content.toString();
        if (signSrc.startsWith("&")) {
            signSrc = signSrc.replaceFirst("&", "");
        }
        return signSrc;
    }