java代码实现RSA加解密，java代码rsa解密
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java代码实现RSA加解密，java代码rsa解密
一.前言
RSA加密算法是一种非对称加密算法。在公开密钥加密和电子商业中RSA被广泛使用。
二.示例代码
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
/**
* RSA加解密工具类
* @author 丶晓权
* 在Linux中使用openssl
* 生成私钥：openssl genrsa -out rsa_private_key.pem 1024
* 把RSA私钥转换成PKCS8格式：openssl pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform PEM -nocrypt
* 生成RSA公钥：openssl rsa -in rsa_private_key.pem -pubout -out rsa_public_key.pem
* 或使用程序中的方法生成密钥对
*
*/
public class SignatureUtil {
/**
* 公钥加密
* @param content加密前内容
* @param publicKey公钥
* @param charset加密编码
* @return 返回加密后的数据
* @throws Exception
*/
public static String rsaEncrypt(String content, String publicKey, String charset) throws Exception {
PublicKey pubKey = getPublicKeyFromX509(new ByteArrayInputStream(publicKey.getBytes()));
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] data = (charset==null||charset.isEmpty()) content.getBytes() : content.getBytes(charset);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > 117) {
cache = cipher.doFinal(data, offSet, 117);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * 117;
}
byte[] encryptedData = Base64.encodeBase64(out.toByteArray());
out.close();
return (charset==null||charset.isEmpty()) new String(encryptedData) : new String(encryptedData, charset);
}
/**
* 私钥解密
* @param content待解密字符串
* @param privateKey 私钥key
* @param charset 编码
* @return 返回的解密后信息
* @throws Exception 异常
*/
public static String rsaDecrypt(String content, String privateKey, String charset) throws Exception {
try {
PrivateKey priKey = getPrivateKeyFromPKCS8(new ByteArrayInputStream(privateKey.getBytes()));
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, priKey);
byte[] encryptedData = (charset==null||charset.isEmpty()) Base64.decodeBase64(content.getBytes())
: Base64.decodeBase64(content.getBytes(charset));
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > 128) {
cache = cipher.doFinal(encryptedData, offSet, 128);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * 128;
}
byte[] decryptedData = out.toByteArray();
out.close();
return (charset==null||charset.isEmpty()) new String(decryptedData) : new String(decryptedData, charset);
} catch (Exception e) {
throw new Exception("EncodeContent = " + content + ",charset = " + charset, e);
}
}
/**
* RSA签名
* @param content
* @param privateKey
* @param charset
* @return
* @throws Exception
*/
public static String rsaSign(String content, String privateKey, String charset) throws Exception {
try {
PrivateKey priKey = getPrivateKeyFromPKCS8(new ByteArrayInputStream(privateKey.getBytes()));
java.security.Signature signature = java.security.Signature.getInstance("SHA1WithRSA");
signature.initSign(priKey);
if (charset==null||charset.isEmpty()) {
signature.update(content.getBytes());
} else {
signature.update(content.getBytes(charset));
}
byte[] signed = signature.sign();
return new String(Base64.encodeBase64(signed));
} catch (Exception e) {
throw new Exception("RSAcontent = " + content + "; charset = " + charset, e);
}
}
/**
* 签名校验
* @param content
* @param sign
* @param publicKey
* @param charset
* @return
* @throws Exception
*/
public static boolean rsaCheckContent(String content, String sign, String publicKey, String charset) throws Exception {
try {
PublicKey pubKey = getPublicKeyFromX509(new ByteArrayInputStream(publicKey.getBytes()));
java.security.Signature signature = java.security.Signature.getInstance("SHA1WithRSA");
signature.initVerify(pubKey);
if (charset==null||charset.isEmpty()) {
signature.update(content.getBytes());
} else {
signature.update(content.getBytes(charset));
}
return signature.verify(Base64.decodeBase64(sign.getBytes()));
} catch (Exception e) {
throw new Exception("RSAcontent=" + content + ",sign=" + sign + ",charset=" + charset, e);
}
}
/**
* 获取公钥
* @param algorithm
* @param ins
* @return
* @throws Exception
*/
public static PublicKey getPublicKeyFromX509(InputStream is) throws Exception {
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
StringWriter writer = new StringWriter();
Reader in=new InputStreamReader(is);
char[] buffer = new char[4096];
int amount;
while ((amount = in.read(buffer)) >= 0) {
writer.write(buffer, 0, amount);
}
byte[] encodedKey = writer.toString().getBytes();
encodedKey = Base64.decodeBase64(encodedKey);
return keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
}
/**
* 获取私钥
* @param algorithm
* @param is
* @return
* @throws Exception
*/
public static PrivateKey getPrivateKeyFromPKCS8(InputStream is) throws Exception {
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
StringWriter writer = new StringWriter();
Reader in=new InputStreamReader(is);
char[] buffer = new char[4096];
int amount;
while ((amount = in.read(buffer)) >= 0) {
writer.write(buffer, 0, amount);
}
byte[] encodedKey = writer.toString().getBytes();
encodedKey = Base64.decodeBase64(encodedKey);
return keyFactory.generatePrivate(new PKCS8EncodedKeySpec(encodedKey));
}
/**
* 生成密钥
* @return
* @throws Exception
*/
public static KeyPair generateKeyPair() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
keyPairGen.initialize(1024);
return keyPairGen.generateKeyPair();
}
/**
* 根据密钥对获取公钥
* @param keyPair
* @return
* @throws UnsupportedEncodingException
*/
public static String getRSAPublicKey(KeyPair keyPair,String charset) throws UnsupportedEncodingException {
PublicKey publicKey = keyPair.getPublic();
byte[] encodeBase64 = Base64.encodeBase64(publicKey.getEncoded());
return (charset==null||charset.isEmpty()) new String(encodeBase64) : new String(encodeBase64, charset);
}
/**
* 根据密钥对获取公钥
* @param keyPair
* @return
* @throws UnsupportedEncodingException
*/
public static String getRSAPrivateKey(KeyPair keyPair,String charset) throws UnsupportedEncodingException {
PrivateKey privateKey = keyPair.getPrivate();
byte[] encodeBase64 = Base64.encodeBase64(privateKey.getEncoded());
return (charset==null||charset.isEmpty()) new String(encodeBase64) : new String(encodeBase64, charset);
}
}
三.测试代码
KeyPair keyPair = SignatureUtil.generateKeyPair();
String privateKey=SignatureUtil.getRSAPrivateKey(keyPair, "utf-8");
String publicKey=SignatureUtil.getRSAPublicKey(keyPair, "utf-8");
String rsaEncrypt = SignatureUtil.rsaEncrypt("测试", publicKey, "UTF-8");//加密
System.out.println(rsaEncrypt);
String rsaEncrypt2 = SignatureUtil.rsaEncrypt("测试", publicKey, "GBK");//加密
System.out.println(rsaEncrypt2);
System.out.println(SignatureUtil.rsaDecrypt(rsaEncrypt, privateKey, "UTF-8"));//解密
System.out.println(SignatureUtil.rsaDecrypt(rsaEncrypt, privateKey, "GBK"));//测试错误解密
System.out.println(SignatureUtil.rsaDecrypt(rsaEncrypt2, privateKey, "GBK"));//解密
String rsaSign = SignatureUtil.rsaSign("测试", privateKey, "UTF-8");//加签
String rsaSign2 = SignatureUtil.rsaSign("测试", privateKey, "GBK");//加签
System.out.println(rsaSign);
System.out.println(rsaSign2);
System.out.println(SignatureUtil.rsaCheckContent("测试", rsaSign, publicKey, "UTF-8"));//验签
System.out.println(SignatureUtil.rsaCheckContent("测试", rsaSign, publicKey, "GBK"));//测试错误验签
System.out.println(SignatureUtil.rsaCheckContent("测试", rsaSign2, publicKey, "GBK"));//验签
四.运行结果
HO2vj3HrzvuWPdF3gW0aqFqD4Ye5BONUcBWwcPEcX02SzD/tyMqsJFcRD1MHYzhlVArRW9+URzUGOpgqCo5oABP5GKP618T1UabJyCzv5sHgADURtERJDF7AXV+ud/5UD8h4koDMCFOa8EVP2CJW4MOWEgiRkY/zJJ9d09XwWyA= j7WKo6Qs1V+D2mq+eBkPJzlnyAH9crx9lSg0rS1/5lxbFQQN5n+XlD6g3JFBng1Y8M5gwJfALKIK2u+i43Ch0utbJF6XsILfKU5ILI2WBoTMbmHcxR+CGS3Tv+ueD5BtfqI1P1R0P1ayMbUDLeHWRcDFs+s3YI3vrB3ZIrXEnyk= 测试 娴嬭瘯 测试 lqi3ve6TO2yYs6rUEf6NuoTGDz6FbvL6XYxyYQbT1L18iSHNolJ+m71V8MYIenkEtVPl75KDs1UMrSTbxA/V5+2O1nWP4Iw+80Eg3536zvI4J1Od/6UVUOZzhubNctVpUXYD7LY4vncvAV/mGSpl6BRqW20HnP9MMVDek1YaF/8= ozcUhv19xhp/FveSQiU6MbBrwrjJBuMp1SiPdRkm4HJD+24r3tOcoHJrawSN99E/EYIAHZlcDPbOkABcMYKRJyHCdc18aRDWO/Sbf5121EWnk2NMdRKOtkuqfEbmSxjTjS/gUmcHEJd8Al4vvtz1kUHF7OdexXn++E38cWdBdIM= true false true
四.Base64工具类
public class Base64 {
static final int CHUNK_SIZE = 76;
static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes();
static final int BASELENGTH = 255;
static final int LOOKUPLENGTH = 64;
static final int EIGHTBIT = 8;
static final int SIXTEENBIT = 16;
static final int TWENTYFOURBITGROUP = 24;
static final int FOURBYTE = 4;
static final int SIGN = -128;
static final byte PAD = (byte) '=';
private static byte[] base64Alphabet = new byte[BASELENGTH];
private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];
static {
for (int i = 0; i < BASELENGTH; i++) {
base64Alphabet[i] = (byte) -1;
}
for (int i = 'Z'; i >= 'A'; i--) {
base64Alphabet[i] = (byte) (i - 'A');
}
for (int i = 'z'; i >= 'a'; i--) {
base64Alphabet[i] = (byte) (i - 'a' + 26);
}
for (int i = '9'; i >= '0'; i--) {
base64Alphabet[i] = (byte) (i - '0' + 52);
}
base64Alphabet['+'] = 62;
base64Alphabet['/'] = 63;
for (int i = 0; i <= 25; i++) {
lookUpBase64Alphabet[i] = (byte) ('A' + i);
}
for (int i = 26, j = 0; i <= 51; i++, j++) {
lookUpBase64Alphabet[i] = (byte) ('a' + j);
}
for (int i = 52, j = 0; i <= 61; i++, j++) {
lookUpBase64Alphabet[i] = (byte) ('0' + j);
}
lookUpBase64Alphabet[62] = (byte) '+';
lookUpBase64Alphabet[63] = (byte) '/';
}
private static boolean isBase64(byte octect) {
if (octect == PAD) {
return true;
} else if (base64Alphabet[octect] == -1) {
return false;
} else {
return true;
}
}
public static boolean isArrayByteBase64(byte[] arrayOctect) {
arrayOctect = discardWhitespace(arrayOctect);
int length = arrayOctect.length;
if (length == 0) {
return true;
}
for (int i = 0; i < length; i++) {
if (!isBase64(arrayOctect[i])) {
return false;
}
}
return true;
}
public static byte[] encodeBase64(byte[] binaryData) {
return encodeBase64(binaryData, false);
}
public static byte[] encodeBase64Chunked(byte[] binaryData) {
return encodeBase64(binaryData, true);
}
public Object decode(Object pObject) throws Exception {
if (!(pObject instanceof byte[])) {
throw new Exception("Parameter supplied to Base64 decode is not a byte[]");
}
return decode((byte[]) pObject);
}
public byte[] decode(byte[] pArray) {
return decodeBase64(pArray);
}
public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) {
int lengthDataBits = binaryData.length * EIGHTBIT;
int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
byte encodedData[] = null;
int encodedDataLength = 0;
int nbrChunks = 0;
if (fewerThan24bits != 0) {
encodedDataLength = (numberTriplets + 1) * 4;
} else {
encodedDataLength = numberTriplets * 4;
}
if (isChunked) {
nbrChunks = (CHUNK_SEPARATOR.length == 0 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE));
encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length;
}
encodedData = new byte[encodedDataLength];
byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;
int encodedIndex = 0;
int dataIndex = 0;
int i = 0;
int nextSeparatorIndex = CHUNK_SIZE;
int chunksSoFar = 0;
for (i = 0; i < numberTriplets; i++) {
dataIndex = i * 3;
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
b3 = binaryData[dataIndex + 2];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
byte val3 = ((b3 & SIGN) == 0) (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3];
encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
encodedIndex += 4;
if (isChunked) {
if (encodedIndex == nextSeparatorIndex) {
System.arraycopy(CHUNK_SEPARATOR, 0, encodedData, encodedIndex, CHUNK_SEPARATOR.length);
chunksSoFar++;
nextSeparatorIndex = (CHUNK_SIZE * (chunksSoFar + 1)) + (chunksSoFar * CHUNK_SEPARATOR.length);
encodedIndex += CHUNK_SEPARATOR.length;
}
}
}
dataIndex = i * 3;
if (fewerThan24bits == EIGHTBIT) {
b1 = binaryData[dataIndex];
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
encodedData[encodedIndex + 2] = PAD;
encodedData[encodedIndex + 3] = PAD;
} else if (fewerThan24bits == SIXTEENBIT) {
b1 = binaryData[dataIndex];
b2 = binaryData[dataIndex + 1];
l = (byte) (b2 & 0x0f);
k = (byte) (b1 & 0x03);
byte val1 = ((b1 & SIGN) == 0) (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
byte val2 = ((b2 & SIGN) == 0) (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
encodedData[encodedIndex + 3] = PAD;
}
if (isChunked) {
if (chunksSoFar < nbrChunks) {
System.arraycopy(CHUNK_SEPARATOR, 0, encodedData, encodedDataLength - CHUNK_SEPARATOR.length,
CHUNK_SEPARATOR.length);
}
}
return encodedData;
}
public static byte[] decodeBase64(byte[] base64Data) {
base64Data = discardNonBase64(base64Data);
if (base64Data.length == 0) {
return new byte[0];
}
int numberQuadruple = base64Data.length / FOURBYTE;
byte decodedData[] = null;
byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
int encodedIndex = 0;
int dataIndex = 0;
int lastData = base64Data.length;
while (base64Data[lastData - 1] == PAD) {
if (--lastData == 0) {
return new byte[0];
}
}
decodedData = new byte[lastData - numberQuadruple];
for (int i = 0; i < numberQuadruple; i++) {
dataIndex = i * 4;
marker0 = base64Data[dataIndex + 2];
marker1 = base64Data[dataIndex + 3];
b1 = base64Alphabet[base64Data[dataIndex]];
b2 = base64Alphabet[base64Data[dataIndex + 1]];
if (marker0 != PAD && marker1 != PAD) {
b3 = base64Alphabet[marker0];
b4 = base64Alphabet[marker1];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
decodedData[encodedIndex + 2] = (byte) (b3 << 6 | b4);
} else if (marker0 == PAD) {
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
} else if (marker1 == PAD) {
b3 = base64Alphabet[marker0];
decodedData[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
decodedData[encodedIndex + 1] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
}
encodedIndex += 3;
}
return decodedData;
}
static byte[] discardWhitespace(byte[] data) {
byte groomedData[] = new byte[data.length];
int bytesCopied = 0;
for (int i = 0; i < data.length; i++) {
switch (data[i]) {
case (byte) ' ':
case (byte) '\n':
case (byte) '\r':
case (byte) '\t':
break;
default:
groomedData[bytesCopied++] = data[i];
}
}
byte packedData[] = new byte[bytesCopied];
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
return packedData;
}
static byte[] discardNonBase64(byte[] data) {
byte groomedData[] = new byte[data.length];
int bytesCopied = 0;
for (int i = 0; i < data.length; i++) {
if (isBase64(data[i])) {
groomedData[bytesCopied++] = data[i];
}
}
byte packedData[] = new byte[bytesCopied];
System.arraycopy(groomedData, 0, packedData, 0, bytesCopied);
return packedData;
}
public Object encode(Object pObject) throws Exception {
if (!(pObject instanceof byte[])) {
throw new Exception("Parameter supplied to Base64 encode is not a byte[]");
}
return encode((byte[]) pObject);
}
public byte[] encode(byte[] pArray) {
return encodeBase64(pArray, false);
}
}
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