前言：
此刻姐妹们对“rsa算法的应用范围”大约比较关切，各位老铁们都想要剖析一些“rsa算法的应用范围”的相关知识。那么小编同时在网上网罗了一些有关“rsa算法的应用范围””的相关内容，希望姐妹们能喜欢，姐妹们一起来学习一下吧！RSA算法简介
RSA 算法
RSA公开密钥密码体制是一种使用不同的加密密钥与解密密钥，“由已知加密密钥推导出解密密钥在计算上是不可行的”密码体制。
在公开密钥密码体制中，加密密钥（即公开密钥）PK是公开信息，而解密密钥（即秘密密钥）SK是需要保密的。加密算法E和解密算法D也都是公开的。虽然解密密钥SK是由公开密钥PK决定的，但却不能根据PK计算出SK。
RSA允许你选择公钥的大小。512位的密钥被视为不安全的；768位的密钥不用担心受到除了国家安全管理（NSA）外的其他事物的危害；1024位的密钥几乎是安全的。
关于RSA概念性的内容不做过多介绍，大家可以自行百度。
Maven 依赖
工具类对于加密后使用Base64进行编码，所以需要依赖Apache Commons Codec。
<dependency> <groupId>commons-codec</groupId> <artifactId>commons-codec</artifactId> <version>1.9</version></dependency><dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.17</version></dependency>
工具类实现
RSAUtil提供了针对文本内容、字节数组内容的加解密实现，RSAUtil工具类可以直接复制使用，代码如下：
package com.arhorchin.securitit.enordecryption.rsa;import java.io.ByteArrayOutputStream;import java.security.Key;import java.security.KeyFactory;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.interfaces.RSAPrivateKey;import java.security.interfaces.RSAPublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;import java.util.HashMap;import java.util.Map;import javax.crypto.Cipher;import org.apache.commons.codec.binary.Base64;import org.apache.log4j.Logger;/** * @author Securitit. * @note RSA加密算法实现. */public class RSAUtil { /** * logger. */ private static Logger logger = Logger.getLogger(RSAUtil.class); /** * 数据编码. */ private static final String CHARSET_UTF8 = "UTF-8"; /** * 加密算法RSA. */ public static final String RSA_NAME = "RSA"; /** * 获取公钥的key. */ public static final String PUBLIC_KEY = "RSAPublicKey"; /** * 获取私钥的key. */ public static final String PRIVATE_KEY = "RSAPrivateKey"; /** * RSA最大加密明文大小. */ public static final int MAX_ENCRYPT_BLOCK = 117; /** * RSA最大解密密文大小. */ public static final int MAX_DECRYPT_BLOCK = 128; /** * RSA密钥长度必须是64的倍数，在512~65536之间。默认是1024. */ public static final int KEY_SIZE = 1024; /** * 生成RSA算法的密钥对. * @return 返回存储密钥对的Map. * @throws Exception 可能的异常. */ public static Map<String, String> generateDesKey() throws Exception { Map<String, String> keysMap = null; KeyPair keyPair = null; RSAPublicKey publicKey = null; RSAPrivateKey privateKey = null; KeyPairGenerator keyPairGenerator = null; // Key存储Map. keysMap = new HashMap<String, String>(2); // 生成RSA秘钥对. keyPairGenerator = KeyPairGenerator.getInstance(RSA_NAME); keyPairGenerator.initialize(KEY_SIZE); keyPair = keyPairGenerator.generateKeyPair(); publicKey = (RSAPublicKey) keyPair.getPublic(); privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 放置到存储Map. keysMap.put(PUBLIC_KEY, Base64.encodeBase64String(publicKey.getEncoded())); keysMap.put(PRIVATE_KEY, Base64.encodeBase64String(privateKey.getEncoded())); return keysMap; } /** * RAS基于Private密钥加密. * @param plainText 原文内容. * @param privateKey 私钥. * @return 加密后内容. * @throws Exception 可能的异常. */ public static String encodeTextByPrivateKey(String plainText, String privateKey) throws Exception { byte[] privateKeyBytes = null; byte[] cipherBytes = null; try { privateKeyBytes = Base64.decodeBase64(privateKey); cipherBytes = encodeByRsa(plainText.getBytes(CHARSET_UTF8), privateKeyBytes, true); return Base64.encodeBase64String(cipherBytes); } catch (Exception ex) { logger.error("RSAUtil.encodeTextByPrivateKey.", ex); return ""; } } /** * RAS基于Private密钥解密. * @param cipherText 密文内容. * @param privateKey 私钥. * @return 解密后内容. * @throws Exception 可能的异常. */ public static String decodeTextByPrivateKey(String cipherText, String privateKey) throws Exception { byte[] privateKeyBytes = null; byte[] plainBytes = null; try { privateKeyBytes = Base64.decodeBase64(privateKey); plainBytes = decodeByRsa(Base64.decodeBase64(cipherText), privateKeyBytes, true); return new String(plainBytes, CHARSET_UTF8); } catch (Exception ex) { logger.error("RSAUtil.decodeTextByPrivateKey.", ex); return ""; } } /** * RAS基于Public密钥加密. * @param plainText 原文内容. * @param PublicKey 公钥. * @return 加密后内容. * @throws Exception 可能的异常. */ public static String encodeTextByPublicKey(String plainText, String publicKey) throws Exception { byte[] publicKeyBytes = null; byte[] cipherBytes = null; try { publicKeyBytes = Base64.decodeBase64(publicKey); cipherBytes = encodeByRsa(plainText.getBytes(CHARSET_UTF8), publicKeyBytes, false); return Base64.encodeBase64String(cipherBytes); } catch (Exception ex) { logger.error("RSAUtil.encodeTextByPublicKey.", ex); return ""; } } /** * RAS基于Public密钥解密. * @param cipherText 密文内容. * @param publicKey 公钥. * @return 解密后内容. * @throws Exception 可能的异常. */ public static String decodeTextByPublicKey(String cipherText, String publicKey) throws Exception { byte[] publicKeyBytes = null; byte[] plainBytes = null; try { publicKeyBytes = Base64.decodeBase64(publicKey); plainBytes = decodeByRsa(Base64.decodeBase64(cipherText), publicKeyBytes, false); return new String(plainBytes, CHARSET_UTF8); } catch (Exception ex) { logger.error("RSAUtil.decodeTextByPublicKey.", ex); return ""; } } /** * RAS基于Private密钥加密. * @param plainBytes 原文内容. * @param privateKey 私钥. * @return 加密后内容. * @throws Exception 可能的异常. */ public static byte[] encodeBytesByPrivateKey(byte[] plainBytes, String privateKey) throws Exception { byte[] privateKeyBytes = null; byte[] cipherBytes = null; try { privateKeyBytes = Base64.decodeBase64(privateKey); cipherBytes = encodeByRsa(plainBytes, privateKeyBytes, true); return cipherBytes; } catch (Exception ex) { logger.error("RSAUtil.encodeTextByPrivateKey.", ex); return new byte[0]; } } /** * RAS基于Private密钥解密. * @param cipherBytes 密文内容. * @param privateKey 私钥. * @return 解密后内容. * @throws Exception 可能的异常. */ public static byte[] decodeBytesByPrivateKey(byte[] cipherBytes, String privateKey) throws Exception { byte[] privateKeyBytes = null; byte[] plainBytes = null; try { privateKeyBytes = Base64.decodeBase64(privateKey); plainBytes = decodeByRsa(cipherBytes, privateKeyBytes, true); return plainBytes; } catch (Exception ex) { logger.error("RSAUtil.decodeTextByPrivateKey.", ex); return new byte[0]; } } /** * RAS基于Public密钥加密. * @param plainBytes 原文内容. * @param PublicKey 公钥. * @return 加密后内容. * @throws Exception 可能的异常. */ public static byte[] encodeBytesByPublicKey(byte[] plainBytes, String publicKey) throws Exception { byte[] publicKeyBytes = null; byte[] cipherBytes = null; try { publicKeyBytes = Base64.decodeBase64(publicKey); cipherBytes = encodeByRsa(plainBytes, publicKeyBytes, false); return cipherBytes; } catch (Exception ex) { logger.error("RSAUtil.encodeTextByPublicKey.", ex); return new byte[0]; } } /** * RAS基于Public密钥解密. * @param cipherBytes 密文内容. * @param publicKey 公钥. * @return 解密后内容. * @throws Exception 可能的异常. */ public static byte[] decodeBytesByPublicKey(byte[] cipherBytes, String publicKey) throws Exception { byte[] publicKeyBytes = null; byte[] plainBytes = null; try { publicKeyBytes = Base64.decodeBase64(publicKey); plainBytes = decodeByRsa(cipherBytes, publicKeyBytes, false); return plainBytes; } catch (Exception ex) { logger.error("RSAUtil.decodeTextByPublicKey.", ex); return new byte[0]; } } /** * 利用RSA进行加密，支持公钥和私钥. * @param plainBytes 待加密原文内容. * @param rsaKeyBytes RSA密钥. * @param isPrivateKey 是否私钥. * @return 加密结果. * @throws Exception 可能的异常. */ public static byte[] encodeByRsa(byte[] plainBytes, byte[] rsaKeyBytes, boolean isPrivateKey) throws Exception { KeyFactory keyFactory = null; Key rsaKeyObj = null; Cipher cipher = null; PKCS8EncodedKeySpec pkcs8KeySpec = null; X509EncodedKeySpec x509KeySpec = null; int plainLength = plainBytes.length; byte[] cipherCacheBytes = null; int cipherPartTotal = 0; ByteArrayOutputStream baos = null; baos = new ByteArrayOutputStream(); // 生成密钥算法对象. keyFactory = KeyFactory.getInstance(RSA_NAME); // 处理加密使用的Key. if (isPrivateKey) { pkcs8KeySpec = new PKCS8EncodedKeySpec(rsaKeyBytes); rsaKeyObj = keyFactory.generatePrivate(pkcs8KeySpec); } else { x509KeySpec = new X509EncodedKeySpec(rsaKeyBytes); rsaKeyObj = keyFactory.generatePublic(x509KeySpec); } cipher = Cipher.getInstance(keyFactory.getAlgorithm()); // 初始化算法密钥. cipher.init(Cipher.ENCRYPT_MODE, rsaKeyObj); // 计算分组，对报文进行分段加密. plainLength = plainBytes.length; cipherPartTotal = (int) Math.ceil((float) plainLength / MAX_ENCRYPT_BLOCK); for (int partIndex = 0; partIndex < cipherPartTotal; partIndex++) { if (partIndex == cipherPartTotal - 1) { cipherCacheBytes = cipher.doFinal(plainBytes, MAX_ENCRYPT_BLOCK * partIndex, plainLength); } else { cipherCacheBytes = cipher.doFinal(plainBytes, MAX_ENCRYPT_BLOCK * partIndex, MAX_ENCRYPT_BLOCK * (partIndex + 1)); } baos.write(cipherCacheBytes, 0, cipherCacheBytes.length); } return baos.toByteArray(); } /** * 利用RSA进行解密，支持公钥和私钥. * @param cipherBytes 待解密原文内容. * @param rsaKeyBytes RSA密钥. * @param isPrivateKey 是否私钥. * @return 加密结果. * @throws Exception 可能的异常. */ public static byte[] decodeByRsa(byte[] cipherBytes, byte[] rsaKeyBytes, boolean isPrivateKey) throws Exception { KeyFactory keyFactory = null; Key rsaKeyObj = null; Cipher cipher = null; PKCS8EncodedKeySpec pkcs8KeySpec = null; X509EncodedKeySpec x509KeySpec = null; int plainLength = cipherBytes.length; byte[] cipherCacheBytes = null; int cipherPartTotal = 0; ByteArrayOutputStream baos = null; baos = new ByteArrayOutputStream(); // 生成密钥算法对象. keyFactory = KeyFactory.getInstance(RSA_NAME); // 处理加密使用的Key. if (isPrivateKey) { pkcs8KeySpec = new PKCS8EncodedKeySpec(rsaKeyBytes); rsaKeyObj = keyFactory.generatePrivate(pkcs8KeySpec); } else { x509KeySpec = new X509EncodedKeySpec(rsaKeyBytes); rsaKeyObj = keyFactory.generatePublic(x509KeySpec); } cipher = Cipher.getInstance(keyFactory.getAlgorithm()); // 初始化算法密钥. cipher.init(Cipher.DECRYPT_MODE, rsaKeyObj); // 计算分组，对报文进行分段解密. plainLength = cipherBytes.length; cipherPartTotal = (int) ((float) plainLength / MAX_ENCRYPT_BLOCK); for (int partIndex = 0; partIndex < cipherPartTotal; partIndex++) { if (partIndex == cipherPartTotal - 1) { cipherCacheBytes = cipher.doFinal(cipherBytes, MAX_ENCRYPT_BLOCK * partIndex, plainLength); } else { cipherCacheBytes = cipher.doFinal(cipherBytes, MAX_ENCRYPT_BLOCK * partIndex, MAX_ENCRYPT_BLOCK * (partIndex + 1)); } baos.write(cipherCacheBytes, 0, cipherCacheBytes.length); } return baos.toByteArray(); }}工具类测试
package com.arhorchin.securitit.enordecryption.rsa;import java.util.Map;import org.apache.commons.codec.binary.Base64;/** * @author Securitit. * @note RSAUtil测试类. */public class RSAUtilTester { public static void main(String[] args) throws Exception { Map<String, String> keyMap = null; String publicKey = null; String privateKey = null; String plaintext = null; String ciphertext = null; byte[] cipherBytes = null; String dePlaintext = null; byte[] dePlainBytes = null; System.out.println("----------------------- 获取RSA密钥对 -------------------------"); keyMap = RSAUtil.generateDesKey(); publicKey = keyMap.get(RSAUtil.PUBLIC_KEY); privateKey = keyMap.get(RSAUtil.PRIVATE_KEY); System.out.println("公钥：" + publicKey); System.out.println("私钥：" + privateKey); System.out.println(); System.out.println("----------------------- 字符串 公钥加密、私钥解密 -------------------------"); plaintext = "这是一段数据原文-公钥加密的原文."; // 公钥进行加密示例. ciphertext = RSAUtil.encodeTextByPublicKey(plaintext, publicKey); System.out.println("公钥加密密文：" + ciphertext); // 私钥进行解密示例. dePlaintext = RSAUtil.decodeTextByPrivateKey(ciphertext, privateKey); System.out.println("私钥解密明文：" + dePlaintext); System.out.println(); System.out.println("----------------------- 字符串 私钥加密、公钥解密 -------------------------"); plaintext = "这是一段数据原文-私钥加密的原文."; // 私钥进行加密示例. ciphertext = RSAUtil.encodeTextByPrivateKey(plaintext, privateKey); System.out.println("私钥加密密文：" + ciphertext); // 公钥进行解密示例. dePlaintext = RSAUtil.decodeTextByPublicKey(ciphertext, publicKey); System.out.println("公钥解密明文：" + dePlaintext); System.out.println("----------------------- 字节数组 公钥加密、私钥解密 -------------------------"); plaintext = "这是一段数据原文-公钥加密的原文."; // 公钥进行加密示例. cipherBytes = RSAUtil.encodeBytesByPublicKey(plaintext.getBytes("UTF-8"), publicKey); ciphertext = Base64.encodeBase64String(cipherBytes); System.out.println("公钥加密密文：" + ciphertext); // 私钥进行解密示例. dePlainBytes = RSAUtil.decodeBytesByPrivateKey(Base64.decodeBase64(ciphertext), privateKey); dePlaintext = new String(dePlainBytes, "UTF-8"); System.out.println("私钥解密明文：" + dePlaintext); System.out.println(); System.out.println("----------------------- 字节数组 私钥加密、公钥解密 -------------------------"); plaintext = "这是一段数据原文-私钥加密的原文."; // 私钥进行加密示例. cipherBytes = RSAUtil.encodeBytesByPrivateKey(plaintext.getBytes("UTF-8"), privateKey); ciphertext = Base64.encodeBase64String(cipherBytes); System.out.println("私钥加密密文：" + ciphertext); // 公钥进行解密示例. dePlainBytes = RSAUtil.decodeBytesByPublicKey(Base64.decodeBase64(ciphertext), publicKey); dePlaintext = new String(dePlainBytes, "UTF-8"); System.out.println("公钥解密明文：" + dePlaintext); }}控制台输出
查看Console中的控制台内容，明文和解密后明文对比，可以确认RSAUtil可以正常工作，控制台如下图：
----------------------- 获取RSA密钥对 -------------------------公钥：MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCQAJFIhf5nNviRgssUabOvM8iqcrXCYmPBX9s37y9z41THaF3B+7Au1+jhGl482LFBRivVl6yeBpfHGT/uNyO9ld9oBo5qbIx7hEApkxHtfd6P4i2zWxlDyqcSxy5QyrZclH7wci8UFzrbQBKD/wKFu80Tft3Neu03HnbD70zOjQIDAQAB私钥：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----------------------- 字符串 公钥加密、私钥解密 -------------------------公钥加密密文：f0T4XxT6L2/t10/hhFD1NWriDgdAQNe9wLp34+Dkyn+w568GUDb8WZPbelmLoARzfz0DXI5fRFyRmbb9Zq5zqrxW1i/Ea0bs7cNnDQ23okPUNyIRdguMneAlrfi+WQgFJWXu9GUSMmFWMVgCAdtAX2I4YPXSmKuS3JX7fIslDxw=私钥解密明文：这是一段数据原文-公钥加密的原文.----------------------- 字符串 私钥加密、公钥解密 -------------------------私钥加密密文：BYI5K56BuSuXp/0Thxc94Tck4W92+bDkeJEIP2qxjyQFst2RB+J6YXWp6LQBCMqEpwwEWgMDBv+U42V9nVMDCTDmugx2oqzT2xys7mMOIhQQsrccISCDzF/lk+CfrxY0hdEc4PJGrqn7vvCoKslBuJEgTL0uUxQirlJ6EVXc76g=公钥解密明文：这是一段数据原文-私钥加密的原文.----------------------- 字节数组 公钥加密、私钥解密 -------------------------公钥加密密文：hvITbYLCnOhrCWDX/DgJNbuJTQWXXFzdPK6bVgep1MH99UyLO7nGKhqNViuVxuTqdVn1nh28Oz1ueA/PMNtiWCXHRUpVYgU957jfvoL17Eugyn9If81EJMpelBP9tdAb7lZJJiECkoUZpQvGImTNIYtONZA9dXGrakT15xO5m+I=私钥解密明文：这是一段数据原文-公钥加密的原文.----------------------- 字节数组 私钥加密、公钥解密 -------------------------私钥加密密文：BYI5K56BuSuXp/0Thxc94Tck4W92+bDkeJEIP2qxjyQFst2RB+J6YXWp6LQBCMqEpwwEWgMDBv+U42V9nVMDCTDmugx2oqzT2xys7mMOIhQQsrccISCDzF/lk+CfrxY0hdEc4PJGrqn7vvCoKslBuJEgTL0uUxQirlJ6EVXc76g=公钥解密明文：这是一段数据原文-私钥加密的原文.
总结
算法实现都很类似，本文只是对算法实现做了整理，在Maven依赖引入的情况下，RSAUtil已经做了简单测试，可以直接使用。
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标签： #rsa算法的应用范围
