java rsa加解密
阿新 • • 發佈:2018-11-11
簡單實用java實現rsa加解密,java內部使用pkcs8格式私鑰,openssl預設為pkcs1私鑰,注意格式
maven專案
//pom.xml <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.dddd</groupId> <artifactId>jrsa</artifactId> <version>1.0</version> <dependencies> <dependency> <groupId>commons-codec</groupId> <artifactId>commons-codec</artifactId> <version>1.11</version> </dependency> <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.5</version> </dependency> </dependencies> </project>
//RSAUtils.java import org.apache.commons.codec.binary.Base64; import org.apache.commons.io.IOUtils; import javax.crypto.Cipher; import java.io.ByteArrayOutputStream; import java.security.*; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.*; import java.util.HashMap; import java.util.Map; public class RSAUtils { public static final String CHARSET = "UTF-8"; public static final String RSA_ALGORITHM = "RSA"; public static Map<String, String> createKeys(int keySize){ //為RSA演算法建立一個KeyPairGenerator物件 KeyPairGenerator kpg; try{ kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM); }catch(NoSuchAlgorithmException e){ throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]"); } //初始化KeyPairGenerator物件,金鑰長度 kpg.initialize(keySize); //生成密匙對 KeyPair keyPair = kpg.generateKeyPair(); //得到公鑰 Key publicKey = keyPair.getPublic(); String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded()); //得到私鑰 Key privateKey = keyPair.getPrivate(); System.out.println("私鑰格式:"+privateKey.getFormat()); String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded()); Map<String, String> keyPairMap = new HashMap<String, String>(); keyPairMap.put("publicKey", publicKeyStr); keyPairMap.put("privateKey", privateKeyStr); return keyPairMap; } /** * 得到公鑰 * @param publicKey 金鑰字串(經過base64編碼) * @throws Exception */ public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException { //通過X509編碼的Key指令獲得公鑰物件 KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM); X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey)); RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec); return key; } /** * 得到私鑰 * @param privateKey 金鑰字串(經過base64編碼) * @throws Exception */ public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException { //通過PKCS#8編碼的Key指令獲得私鑰物件 KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey)); RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec); return key; } /** * 公鑰加密 * @param data * @param publicKey * @return */ public static String publicEncrypt(String data, RSAPublicKey publicKey){ try{ Cipher cipher = Cipher.getInstance(RSA_ALGORITHM); cipher.init(Cipher.ENCRYPT_MODE, publicKey); return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength())); }catch(Exception e){ throw new RuntimeException("加密字串[" + data + "]時遇到異常", e); } } /** * 私鑰解密 * @param data * @param privateKey * @return */ public static String privateDecrypt(String data, RSAPrivateKey privateKey){ try{ Cipher cipher = Cipher.getInstance(RSA_ALGORITHM); cipher.init(Cipher.DECRYPT_MODE, privateKey); return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET); }catch(Exception e){ throw new RuntimeException("解密字串[" + data + "]時遇到異常", e); } } /** * 私鑰加密 * @param data * @param privateKey * @return */ public static String privateEncrypt(String data, RSAPrivateKey privateKey){ try{ Cipher cipher = Cipher.getInstance(RSA_ALGORITHM); cipher.init(Cipher.ENCRYPT_MODE, privateKey); return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength())); }catch(Exception e){ throw new RuntimeException("加密字串[" + data + "]時遇到異常", e); } } /** * 公鑰解密 * @param data * @param publicKey * @return */ public static String publicDecrypt(String data, RSAPublicKey publicKey){ try{ Cipher cipher = Cipher.getInstance(RSA_ALGORITHM); cipher.init(Cipher.DECRYPT_MODE, publicKey); return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET); }catch(Exception e){ throw new RuntimeException("解密字串[" + data + "]時遇到異常", e); } } private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){ int maxBlock = 0; if(opmode == Cipher.DECRYPT_MODE){ maxBlock = keySize / 8; }else{ maxBlock = keySize / 8 - 11; } ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] buff; int i = 0; try{ while(datas.length > offSet){ if(datas.length-offSet > maxBlock){ buff = cipher.doFinal(datas, offSet, maxBlock); }else{ buff = cipher.doFinal(datas, offSet, datas.length-offSet); } out.write(buff, 0, buff.length); i++; offSet = i * maxBlock; } }catch(Exception e){ throw new RuntimeException("加解密閥值為["+maxBlock+"]的資料時發生異常", e); } byte[] resultDatas = out.toByteArray(); IOUtils.closeQuietly(out); return resultDatas; } }
//Test.java import java.util.Map; public class Test { public static void main(String[] args) throws Exception{ Map<String, String> keyMap = RSAUtils.createKeys(1024); String publicKey = keyMap.get("publicKey"); String privateKey = keyMap.get("privateKey"); System.out.println("公鑰: \n\r" + publicKey); System.out.println("私鑰: \n\r" + privateKey); System.out.println("公鑰加密——私鑰解密"); String str = "內容測試--test!!!"; System.out.println("\r明文:\r\n" + str); System.out.println("\r明文大小:\r\n" + str.getBytes().length); String encodedData = RSAUtils.publicEncrypt(str, RSAUtils.getPublicKey(publicKey)); System.out.println("密文:\r\n" + encodedData); String decodedData = RSAUtils.privateDecrypt(encodedData, RSAUtils.getPrivateKey(privateKey)); System.out.println("解密後文字: \r\n" + decodedData); } }