摘要：
Java-文件加密传输（摘要+签名） Java-文件加密传输文件加密传输其实就是将文件以二进制格式进行传输。其中加密文件主要由：源文件二进制文件、源文件数字摘要、数字签名、特征码等等组成。
文件加密传输其实就是将文件以二进制格式进行传输。
其中加密文件主要由：源文件二进制文件、源文件数字摘要、数字签名、特征码等等组成。
摘要可确认文件的唯一性，数字签名则是对摘要进行了加密。
本文主要记录使用RSA加密方式
其中生成RSA密钥主要介绍二种方式：
1、安装openssl情况下使用Linux命令生成
2、Java代码实现一、公私钥生成
1、linux
1、查看openssl版本
openssl version -a
2、生成私钥
openssl genrsa -out rsa_private_key.pem 2048
会生成rsa_private_key.pem私钥文件，私钥文件不能使用
3、生成公钥
openssl rsa -in rsa_private_key.pem -out rsa_public_key.pem -puboutopenssl pkcs8 -topk8 -inform PEM -outform DER -in private_key.pem -out private_key.der -nocrypt
私钥文件不能使用
4、私钥文件PKCS#8编码
openssl pkcs8 -topk8 -in rsa_private_key.pem -out pkcs8_rsa_private_key.pem
此处生成的私钥文件方可用于Java
2、Java
importjava.io.BufferedReader; importjava.io.BufferedWriter; importjava.io.FileReader; importjava.io.FileWriter; importjava.io.IOException; importjava.security.InvalidKeyException; importjava.security.KeyFactory; importjava.security.KeyPair; importjava.security.KeyPairGenerator; importjava.security.NoSuchAlgorithmException; importjava.security.SecureRandom; importjava.security.interfaces.RSAPrivateKey; importjava.security.interfaces.RSAPublicKey; importjava.security.spec.InvalidKeySpecException; importjava.security.spec.PKCS8EncodedKeySpec; importjava.security.spec.X509EncodedKeySpec; importjavax.crypto.BadPaddingException; importjavax.crypto.Cipher; importjavax.crypto.IllegalBlockSizeException; importjavax.crypto.NoSuchPaddingException; importorg.apache.commons.codec.binary.Base64; public classRSAEncrypt { /*** 字节数据转字符串专用集合 */ private static final char[] HEX_CHAR = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'}; private static final String PRIVATE_BEGIN = "-----BEGIN PRIVATE KEY-----"; private static final String PRIVATE_END = "-----END PRIVATE KEY-----"; private static final String PUBLIC_BEGIN = "-----BEGIN PUBLIC KEY-----"; private static final String PUBLIC_END = "-----END PUBLIC KEY-----"; /*** 1、随机生成密钥对 * * @paramfilePath 密钥存放目录 */ public voidgenKeyPair(String filePath) { //KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象 KeyPairGenerator keyPairGen = null; try{ keyPairGen = KeyPairGenerator.getInstance("RSA"); } catch(NoSuchAlgorithmException e) { e.printStackTrace(); } //初始化密钥对生成器，密钥大小为96-1024位 keyPairGen.initialize(1024, newSecureRandom()); //生成一个密钥对，保存在keyPair中 KeyPair keyPair =keyPairGen.generateKeyPair(); //得到私钥 RSAPrivateKey privateKey =(RSAPrivateKey) keyPair.getPrivate(); //得到公钥 RSAPublicKey publicKey =(RSAPublicKey) keyPair.getPublic(); try{ //得到公钥字符串 Base64 base64 = newBase64(); String publicKeyString = newString(base64.encode(publicKey.getEncoded())); //得到私钥字符串 String privateKeyString = newString(base64.encode(privateKey.getEncoded())); //将密钥对写入到文件 FileWriter pubfw = new FileWriter(filePath + "\publicKey.pem"); FileWriter prifw = new FileWriter(filePath + "\privateKey.pem"); BufferedWriter pubbw = newBufferedWriter(pubfw); BufferedWriter pribw = newBufferedWriter(prifw); pubbw.write(publicKeyString); pribw.write(privateKeyString); pubbw.flush(); pubbw.close(); pubfw.close(); pribw.flush(); pribw.close(); prifw.close(); } catch(Exception e) { e.printStackTrace(); } } /*** 2、从本地文件中读取公钥 * * @parampath 公钥路径 * @return公钥字符串 * @throwsException 异常信息 */ public String loadPublicKeyByFile(String path) throwsException { try{ BufferedReader br = new BufferedReader(newFileReader(path)); String readLine = null; StringBuilder sb = newStringBuilder(); while ((readLine = br.readLine()) != null) { //去除公钥头部底部 if (!readLine.equals(PUBLIC_BEGIN) && !readLine.equals(PUBLIC_END)) { sb.append(readLine); } } br.close(); returnsb.toString(); } catch(IOException e) { throw new Exception("公钥数据流读取错误"); } catch(NullPointerException e) { throw new Exception("公钥输入流为空"); } } /*** 3、字符串公钥转公钥对象 * * @parampublicKeyStr 公钥字符串类型 * @return公钥对象 * @throwsException 异常信息 */ publicRSAPublicKey loadPublicKeyByStr(String publicKeyStr) throwsException { try{ Base64 base64 = newBase64(); byte[] buffer =base64.decode(publicKeyStr); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); X509EncodedKeySpec keySpec = newX509EncodedKeySpec(buffer); return(RSAPublicKey) keyFactory.generatePublic(keySpec); } catch(NoSuchAlgorithmException e) { throw new Exception("无此算法"); } catch(InvalidKeySpecException e) { throw new Exception("公钥非法"); } catch(NullPointerException e) { throw new Exception("公钥数据为空"); } } /*** 4、从本地文件中读取私钥 * * @parampath 私钥文件路径 * @return私钥字符串 * @throwsException 异常信息 */ public String loadPrivateKeyByFile(String path) throwsException { try{ BufferedReader br = new BufferedReader(newFileReader(path)); String readLine = null; StringBuilder sb = newStringBuilder(); while ((readLine = br.readLine()) != null) { //去除私钥头部底部 if (!readLine.equals(PRIVATE_BEGIN) && !readLine.equals(PRIVATE_END)) { sb.append(readLine); } else{ } } br.close(); returnsb.toString(); } catch(IOException e) { throw new Exception("私钥数据读取错误"); } catch(NullPointerException e) { throw new Exception("私钥输入流为空"); } } /*** 5、字符串公钥转公钥对象 * * @paramprivateKeyStr 私钥字符串类型 * @return私钥对象 * @throwsException 异常信息 */ publicRSAPrivateKey loadPrivateKeyByStr(String privateKeyStr) throwsException { try{ Base64 base64 = newBase64(); byte[] buffer =base64.decode(privateKeyStr); PKCS8EncodedKeySpec keySpec = newPKCS8EncodedKeySpec(buffer); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); return(RSAPrivateKey) keyFactory.generatePrivate(keySpec); } catch(NoSuchAlgorithmException e) { throw new Exception("无此算法"); } catch(InvalidKeySpecException e) { throw new Exception("私钥非法"); } catch(NullPointerException e) { throw new Exception("私钥数据为空"); } } /*** 6、公钥加密过程 * * @parampublicKey 公钥 * @paramplainTextData 明文数据 * @return* @throwsException 加密过程中的异常信息 */ public byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) throwsException { if (publicKey == null) { throw new Exception("加密公钥为空, 请设置"); } Cipher cipher = null; try{ //使用默认RSA cipher = Cipher.getInstance("RSA"); //cipher= Cipher.getInstance("RSA", new BouncyCastleProvider()); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] output =cipher.doFinal(plainTextData); returnoutput; } catch(NoSuchAlgorithmException e) { throw new Exception("无此加密算法"); } catch(NoSuchPaddingException e) { e.printStackTrace(); return null; } catch(InvalidKeyException e) { throw new Exception("加密公钥非法,请检查"); } catch(IllegalBlockSizeException e) { throw new Exception("明文长度非法"); } catch(BadPaddingException e) { throw new Exception("明文数据已损坏"); } } /*** 7、私钥加密过程 * * @paramprivateKey 私钥 * @paramplainTextData 明文数据 * @return* @throwsException 加密过程中的异常信息 */ public byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData) throwsException { if (privateKey == null) { throw new Exception("加密私钥为空, 请设置"); } Cipher cipher = null; try{ //使用默认RSA cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, privateKey); byte[] output =cipher.doFinal(plainTextData); returnoutput; } catch(NoSuchAlgorithmException e) { throw new Exception("无此加密算法"); } catch(NoSuchPaddingException e) { e.printStackTrace(); return null; } catch(InvalidKeyException e) { throw new Exception("加密私钥非法,请检查"); } catch(IllegalBlockSizeException e) { throw new Exception("明文长度非法"); } catch(BadPaddingException e) { throw new Exception("明文数据已损坏"); } } /*** 8、私钥解密过程 * * @paramprivateKey 私钥 * @paramcipherData 密文数据 * @return明文 * @throwsException 解密过程中的异常信息 */ public byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) throwsException { if (privateKey == null) { throw new Exception("解密私钥为空, 请设置"); } Cipher cipher = null; try{ //使用默认RSA cipher = Cipher.getInstance("RSA"); //cipher= Cipher.getInstance("RSA", new BouncyCastleProvider()); cipher.init(Cipher.DECRYPT_MODE, privateKey); byte[] output =cipher.doFinal(cipherData); returnoutput; } catch(NoSuchAlgorithmException e) { throw new Exception("无此解密算法"); } catch(NoSuchPaddingException e) { e.printStackTrace(); return null; } catch(InvalidKeyException e) { throw new Exception("解密私钥非法,请检查"); } catch(IllegalBlockSizeException e) { throw new Exception("密文长度非法"); } catch(BadPaddingException e) { throw new Exception("密文数据已损坏"); } } /*** 9、公钥解密过程 * * @parampublicKey 公钥 * @paramcipherData 密文数据 * @return明文 * @throwsException 解密过程中的异常信息 */ public byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData) throwsException { if (publicKey == null) { throw new Exception("解密公钥为空, 请设置"); } Cipher cipher = null; try{ //使用默认RSA cipher = Cipher.getInstance("RSA"); //cipher= Cipher.getInstance("RSA", new BouncyCastleProvider()); cipher.init(Cipher.DECRYPT_MODE, publicKey); byte[] output =cipher.doFinal(cipherData); returnoutput; } catch(NoSuchAlgorithmException e) { throw new Exception("无此解密算法"); } catch(NoSuchPaddingException e) { e.printStackTrace(); return null; } catch(InvalidKeyException e) { throw new Exception("解密公钥非法,请检查"); } catch(IllegalBlockSizeException e) { throw new Exception("密文长度非法"); } catch(BadPaddingException e) { throw new Exception("密文数据已损坏"); } } /*** 10、字节数据转十六进制字符串 * * @paramdata 输入数据 * @return十六进制内容 */ public String byteArrayToString(byte[] data) { StringBuilder stringBuilder = newStringBuilder(); for (int i = 0; i < data.length; i++) { //取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移 stringBuilder.append(HEX_CHAR[(data[i] & 0xf0) >>> 4]); //取出字节的低四位 作为索引得到相应的十六进制标识符 stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]); if (i < data.length - 1) { stringBuilder.append(' '); } } returnstringBuilder.toString(); } }
二、调用
/*** 生成加密后文件 * * @paramoldFilePath 需要加密文件路径+名称 * @paramnewFilePath 加密后文件路径+名称 * @paramprivatePath 私钥文件路径+名称 */ public voidfileEncrypt(String oldFilePath, String newFilePath, String privatePath) { ByteUtil byteUtil = newByteUtil(); //文件格式：特征码+原始升级包长度+数字签名长度+原始包内容+数字签名 byte[] code = byteUtil.intToByteArray(0x9F2308DC); RSAEncrypt rsaEncrypt = newRSAEncrypt(); try{ //1、特征码写入 OutputStream out = new FileOutputStream(newFile(newFilePath)); out.write(code, 0, 4); //2、原始升级包长度写入 byte[] fileByte =byteUtil.File2byte(oldFilePath); int L1 =fileByte.length; byte[] a =byteUtil.intToByteArray(L1); out.write(a, 0, 4); //文件摘要生成 MsgDigestDemo msgDigestDemo = newMsgDigestDemo(); MessageDigest md5Digest = MessageDigest.getInstance("MD5"); md5Digest.update(msgDigestDemo.fileBytes(oldFilePath)); byte[] md5Encoded =md5Digest.digest(); log.info("==========MD5摘要:{}==========", Base64.encodeBase64URLSafeString(md5Encoded)); String privateKey =rsaEncrypt.loadPrivateKeyByFile(privatePath); RSAPrivateKey privateKeyfile =rsaEncrypt.loadPrivateKeyByStr(privateKey); //生成签名(摘要加密过程) byte[] signature =rsaEncrypt.encrypt(privateKeyfile, md5Encoded); //3、签名长度 int L2 =signature.length; byte[] c =byteUtil.intToByteArray(L2); out.write(c, 0, 4); //4、原始升级包内容写入 out.write(fileByte, 0, L1); //5、数字签名写入 out.write(signature, 0, L2); out.flush(); out.close(); } catch(IOException e) { e.printStackTrace(); } catch(Exception e) { e.printStackTrace(); } }
MD5摘要计算
public classMsgDigestDemo { public byte[] fileBytes(String filePath) { try{ File file = newFile(filePath); ByteArrayOutputStream out = new ByteArrayOutputStream(1024); FileInputStream in = newFileInputStream(file); byte[] fileByte = new byte[1024]; intn; while ((n = in.read(fileByte)) != -1) { out.write(fileByte, 0, n); } in.close(); byte[] data =out.toByteArray(); out.close(); returndata; } catch(IOException e) { e.printStackTrace(); } return null; } }