Java，RSA加解密算法
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RSAUtils:
import java.io.ByteArrayOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
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;
/** *//**
* <p>
* RSA公钥/私钥/签名工具包
* </p>
* <p>
* 罗纳德·李维斯特（Ron [R]ivest）、阿迪·萨莫尔（Adi [S]hamir）和伦纳德·阿德曼（Leonard [A]dleman）
* </p>
* <p>
* 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/>
* 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/>
* 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全
* </p>
*
* @author IceWee
* @date 2012-4-26
* @version 1.0
*/
public class RSAUtils
/** *//**
* 加密算法RSA
*/
public static final String KEY_ALGORITHM = "RSA";
/** *//**
* 签名算法
*/
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
/** *//**
* 获取公钥的key
*/
private static final String PUBLIC_KEY = "RSAPublicKey";
/** *//**
* 获取私钥的key
*/
private static final String PRIVATE_KEY = "RSAPrivateKey";
/** *//**
* RSA最大加密明文大小
*/
private static final int MAX_ENCRYPT_BLOCK = 117;
/** *//**
* RSA最大解密密文大小
*/
private static final int MAX_DECRYPT_BLOCK = 128;
/** *//**
* <p>
* 生成密钥对(公钥和私钥)
* </p>
*
* @return
* @throws Exception
*/
public static Map<String, Object> genKeyPair() throws Exception
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
/** *//**
* <p>
* 用私钥对信息生成数字签名
* </p>
*
* @param data 已加密数据
* @param privateKey 私钥(BASE64编码)
*
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception
byte[] keyBytes = Base64Coder.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(data);
return new String(Base64Coder.encode(signature.sign()));
/** *//**
* <p>
* 校验数字签名
* </p>
*
* @param data 已加密数据
* @param publicKey 公钥(BASE64编码)
* @param sign 数字签名
*
* @return
* @throws Exception
*
*/
public static boolean verify(byte[] data, String publicKey, String sign)
throws Exception
byte[] keyBytes = Base64Coder.decode(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64Coder.decode(sign));
/** *//**
* <P>
* 私钥解密
* </p>
*
* @param encryptedData 已加密数据
* @param privateKey 私钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
throws Exception
byte[] keyBytes = Base64Coder.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateK);
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 > MAX_DECRYPT_BLOCK)
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
else
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
/** *//**
* <p>
* 公钥解密
* </p>
*
* @param encryptedData 已加密数据
* @param publicKey 公钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
throws Exception
byte[] keyBytes = Base64Coder.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicK);
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 > MAX_DECRYPT_BLOCK)
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
else
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
/** *//**
* <p>
* 公钥加密
* </p>
*
* @param data 源数据
* @param publicKey 公钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(byte[] data, String publicKey)
throws Exception
byte[] keyBytes = Base64Coder.decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 对数据加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicK);
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 > MAX_ENCRYPT_BLOCK)
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
else
cache = cipher.doFinal(data, offSet, inputLen - offSet);
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
/** *//**
* <p>
* 私钥加密
* </p>
*
* @param data 源数据
* @param privateKey 私钥(BASE64编码)
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
throws Exception
byte[] keyBytes = Base64Coder.decode(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateK);
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 > MAX_ENCRYPT_BLOCK)
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
else
cache = cipher.doFinal(data, offSet, inputLen - offSet);
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
/** *//**
* <p>
* 获取私钥
* </p>
*
* @param keyMap 密钥对
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap)
throws Exception
Key key = (Key) keyMap.get(PRIVATE_KEY);
return new String(Base64Coder.encode(key.getEncoded()));
/** *//**
* <p>
* 获取公钥
* </p>
*
* @param keyMap 密钥对
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap)
throws Exception
Key key = (Key) keyMap.get(PUBLIC_KEY);
return new String(Base64Coder.encode(key.getEncoded()));
Base64Coder:
public class Base64Coder
private static final String systemLineSeparator = System.getProperty("line.separator");
// Mapping table from 6-bit nibbles to Base64 characters.
private static final char[] map1 = new char[64];
static
int i = 0;
for (char c = 'A'; c <= 'Z'; c++)
map1[i++] = c;
for (char c = 'a'; c <= 'z'; c++)
map1[i++] = c;
for (char c = '0'; c <= '9'; c++)
map1[i++] = c;
map1[i++] = '+';
map1[i++] = '/';
// Mapping table from Base64 characters to 6-bit nibbles.
private static final byte[] map2 = new byte[128];
static
for (int i = 0; i < map2.length; i++)
map2[i] = -1;
for (int i = 0; i < 64; i++)
map2[map1[i]] = (byte) i;
/**
* Encodes a string into Base64 format. No blanks or line breaks are
* inserted.
*
* @param s
* A String to be encoded.
* @return A String containing the Base64 encoded data.
*/
public static String encodeString(String s)
return new String(encode(s.getBytes()));
/**
* Encodes a byte array into Base 64 format and breaks the output into lines
* of 76 characters. This method is compatible with
* <code>sun.misc.BASE64Encoder.encodeBuffer(byte[])</code>.
*
* @param in
* An array containing the data bytes to be encoded.
* @return A String containing the Base64 encoded data, broken into lines.
*/
public static String encodeLines(byte[] in)
return encodeLines(in, 0, in.length, 76, systemLineSeparator);
/**
* Encodes a byte array into Base 64 format and breaks the output into
* lines.
*
* @param in
* An array containing the data bytes to be encoded.
* @param iOff
* Offset of the first byte in <code>in</code> to be processed.
* @param iLen
* Number of bytes to be processed in <code>in</code>, starting
* at <code>iOff</code>.
* @param lineLen
* Line length for the output data. Should be a multiple of 4.
* @param lineSeparator
* The line separator to be used to separate the output lines.
* @return A String containing the Base64 encoded data, broken into lines.
*/
public static String encodeLines(byte[] in, int iOff, int iLen,
int lineLen, String lineSeparator)
int blockLen = (lineLen * 3) / 4;
if (blockLen <= 0)
throw new IllegalArgumentException();
int lines = (iLen + blockLen - 1) / blockLen;
int bufLen = ((iLen + 2) / 3) * 4 + lines * lineSeparator.length();
StringBuilder buf = new StringBuilder(bufLen);
int ip = 0;
while (ip < iLen)
int l = Math.min(iLen - ip, blockLen);
buf.append(encode(in, iOff + ip, l));
buf.append(lineSeparator);
ip += l;
return buf.toString();
/**
* Encodes a byte array into Base64 format. No blanks or line breaks are
* inserted in the output.
*
* @param in
* An array containing the data bytes to be encoded.
* @return A character array containing the Base64 encoded data.
*/
public static char[] encode(byte[] in)
return encode(in, 0, in.length);
/**
* Encodes a byte array into Base64 format. No blanks or line breaks are
* inserted in the output.
*
* @param in
* An array containing the data bytes to be encoded.
* @param iLen
* Number of bytes to process in <code>in</code>.
* @return A character array containing the Base64 encoded data.
*/
public static char[] encode(byte[] in, int iLen)
return encode(in, 0, iLen);
/**
* Encodes a byte array into Base64 format. No blanks or line breaks are
* inserted in the output.
*
* @param in
* An array containing the data bytes to be encoded.
* @param iOff
* Offset of the first byte in <code>in</code> to be processed.
* @param iLen
* Number of bytes to process in <code>in</code>, starting at
* <code>iOff</code>.
* @return A character array containing the Base64 encoded data.
*/
public static char[] encode(byte[] in, int iOff, int iLen)
int oDataLen = (iLen * 4 + 2) / 3; // output length without padding
int oLen = ((iLen + 2) / 3) * 4; // output length including padding
char[] out = new char[oLen];
int ip = iOff;
int iEnd = iOff + iLen;
int op = 0;
while (ip < iEnd)
int i0 = in[ip++] & 0xff;
int i1 = ip < iEnd ? in[ip++] & 0xff : 0;
int i2 = ip < iEnd ? in[ip++] & 0xff : 0;
int o0 = i0 >>> 2;
int o1 = ((i0 & 3) << 4) | (i1 >>> 4);
int o2 = ((i1 & 0xf) << 2) | (i2 >>> 6);
int o3 = i2 & 0x3F;
out[op++] = map1[o0];
out[op++] = map1[o1];
out[op] = op < oDataLen ? map1[o2] : '=';
op++;
out[op] = op < oDataLen ? map1[o3] : '=';
op++;
return out;
/**
* Decodes a string from Base64 format. No blanks or line breaks are allowed
* within the Base64 encoded input data.
*
* @param s
* A Base64 String to be decoded.
* @return A String containing the decoded data.
* @throws IllegalArgumentException
* If the input is not valid Base64 encoded data.
*/
public static String decodeString(String s)
return new String(decode(s));
/**
* Decodes a byte array from Base64 format and ignores line separators, tabs
* and blanks. CR, LF, Tab and Space characters are ignored in the input
* data. This method is compatible with
* <code>sun.misc.BASE64Decoder.decodeBuffer(String)</code>.
*
* @param s
* A Base64 String to be decoded.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException
* If the input is not valid Base64 encoded data.
*/
public static byte[] decodeLines(String s)
char[] buf = new char[s.length()];
int p = 0;
for (int ip = 0; ip < s.length(); ip++)
char c = s.charAt(ip);
if (c != ' ' && c != '\\r' && c != '\\n' && c != '\\t')
buf[p++] = c;
return decode(buf, 0, p);
/**
* Decodes a byte array from Base64 format. No blanks or line breaks are
* allowed within the Base64 encoded input data.
*
* @param s
* A Base64 String to be decoded.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException
* If the input is not valid Base64 encoded data.
*/
public static byte[] decode(String s)
return decode(s.toCharArray());
/**
* Decodes a byte array from Base64 format. No blanks or line breaks are
* allowed within the Base64 encoded input data.
*
* @param in
* A character array containing the Base64 encoded data.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException
* If the input is not valid Base64 encoded data.
*/
public static byte[] decode(char[] in)
return decode(in, 0, in.length);
/**
* Decodes a byte array from Base64 format. No blanks or line breaks are
* allowed within the Base64 encoded input data.
*
* @param in
* A character array containing the Base64 encoded data.
* @param iOff
* Offset of the first character in <code>in</code> to be
* processed.
* @param iLen
* Number of characters to process in <code>in</code>, starting
* at <code>iOff</code>.
* @return An array containing the decoded data bytes.
* @throws IllegalArgumentException
* If the input is not valid Base64 encoded data.
*/
public static byte[] decode(char[] in, int iOff, int iLen)
if (iLen % 4 != 0)
throw new IllegalArgumentException(
"Length of Base64 encoded input string is not a multiple of 4.");
while (iLen > 0 && in[iOff + iLen - 1] == '=')
iLen--;
int oLen = (iLen * 3) / 4;
byte[] out = new byte[oLen];
int ip = iOff;
int iEnd = iOff + iLen;
int op = 0;
while (ip < iEnd)
int i0 = in[ip++];
int i1 = in[ip++];
int i2 = ip < iEnd ? in[ip++] : 'A';
int i3 = ip < iEnd ? in[ip++] : 'A';
if (i0 > 127 || i1 > 127 || i2 > 127 || i3 > 127)
throw new IllegalArgumentException(
"Illegal character in Base64 encoded data.");
int b0 = map2[i0];
int b1 = map2[i1];
int b2 = map2[i2];
int b3 = map2[i3];
if (b0 < 0 || b1 < 0 || b2 < 0 || b3 < 0)
throw new IllegalArgumentException(
"Illegal character in Base64 encoded data.");
int o0 = (b0 << 2) | (b1 >>> 4);
int o1 = ((b1 & 0xf) << 4) | (b2 >>> 2);
int o2 = ((b2 & 3) << 6) | b3;
out[op++] = (byte) o0;
if (op < oLen)
out[op++] = (byte) o1;
if (op < oLen)
out[op++] = (byte) o2;
return out;
// Dummy constructor.
private Base64Coder()
测试代码：
import java.util.Map;
public class RSATester
static String publicKey;
static String privateKey;
public static void main(String[] args) throws Exception
getKey();
test();
testSign();
static void getKey()
try
Map<String, Object> keyMap = RSAUtils.genKeyPair();
publicKey = RSAUtils.getPublicKey(keyMap);
privateKey = RSAUtils.getPrivateKey(keyMap);
System.out.println("公钥: \\n" + publicKey);
System.out.println("私钥： \\n" + privateKey);
catch (Exception e)
e.printStackTrace();
static void test() throws Exception
System.out.println("====================================================");
System.out.println("Test1:公钥加密——>私钥解密");
String source = "这是测试一:用公钥加密，私钥来解密!";
System.out.println("加密前文字：\\r\\n" + source);
byte[] data = source.getBytes();
byte[] encodedData = RSAUtils.encryptByPublicKey(data, publicKey);
System.out.println("加密后文字：\\r\\n" + new String(encodedData));
byte[] decodedData = RSAUtils.decryptByPrivateKey(encodedData, privateKey);
String target = new String(decodedData);
System.out.println("解密后文字: \\r\\n" + target);
System.out.println("====================================================");
static void testSign() throws Exception
System.out.println("Test2:私钥加密签名——>公钥验签解密");
String source = "这是测试二:用私钥加密并且签名，然后用公钥验签并解密!";
System.out.println("加密签名前文字：\\r\\n" + source);
System.out.println("私钥加密");
byte[] data = source.getBytes();
byte[] encodedData = RSAUtils.encryptByPrivateKey(data, privateKey);
System.out.println("加密后：\\r\\n" + new String(encodedData));
System.out.println("私钥签名");
String sign = RSAUtils.sign(encodedData, privateKey);
System.out.println("签名:\\r" + sign);
System.out.println("====================================================");
System.out.println("公钥验签");
boolean status = RSAUtils.verify(encodedData, publicKey, sign);
System.out.println("验证结果:" + status);
System.out.println("公钥解密");
byte[] decodedData = RSAUtils.decryptByPublicKey(encodedData, publicKey);
String target = new String(decodedData);
System.out.println("解密后: \\r\\n" + target);
另外，下面附上MD5加密的方法：
public static String getMD5(String instr)
String s = null;
char hexDigits[] = '0', '1', '2', '3', '4', '5', '6', '7', '8', '9','a', 'b', 'c', 'd', 'e', 'f' ;
try
java.security.MessageDigest md = java.security.MessageDigest.getInstance("MD5");
md.update(instr.getBytes());
byte tmp[] = md.digest();
char str[] = new char[16 * 2];
int k = 0;
for (int i = 0; i < 16; i++)
byte byte0 = tmp[i];
str[k++] = hexDigits[byte0 >>> 4 & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
s = new String(str).toUpperCase();
catch (Exception e)
e.printStackTrace();
return null;
return s;
友情链接：
http://blog.csdn.net/centralperk/article/details/8538697
http://blog.csdn.net/uikoo9/article/details/27983071
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