rsa算法代码java,rsa算法代码实现

请高手指教如何用java编写RSA算法?谢谢

你是用rsa算法去加密,还是要自己编写一个rsa算法?

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RSA是非对称加密算法,可以用它通过KeyPairGenerator来生成KeyPari,它里面有公钥和私钥。

通过Cipher.getInstance("PBEWithMD5AndDES")得到Cipher对象并初始化为加密/解密模式。最doFinal即可完成加解密。除了生成KeyPari外,还可以通过RSA算法的证书和密钥库来得到公/私钥。如果阁下想自己编写一个RSA算法的,本人就无能为力了。

求JAVA编写的RSA加密算法

代码如下:main方法用于测试的,不是算法本身。

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.security.SecureRandom;

import javax.crypto.Cipher;

public class RSACrypto

{

private final static String RSA = "RSA";

public static PublicKey uk;

public static PrivateKey rk;

public static void generateKey() throws Exception

{

KeyPairGenerator gen = KeyPairGenerator.getInstance(RSA);

gen.initialize(512, new SecureRandom());

KeyPair keyPair = gen.generateKeyPair();

uk = keyPair.getPublic();

rk = keyPair.getPrivate();

}

private static byte[] encrypt(String text, PublicKey pubRSA) throws Exception

{

Cipher cipher = Cipher.getInstance(RSA);

cipher.init(Cipher.ENCRYPT_MODE, pubRSA);

return cipher.doFinal(text.getBytes());

}

public final static String encrypt(String text)

{

try {

return byte2hex(encrypt(text, uk));

}

catch(Exception e)

{

e.printStackTrace();

}

return null;

}

public final static String decrypt(String data)

{

try{

return new String(decrypt(hex2byte(data.getBytes())));

}

catch (Exception e)

{

e.printStackTrace();

}

return null;

}

private static byte[] decrypt(byte[] src) throws Exception

{

Cipher cipher = Cipher.getInstance(RSA);

cipher.init(Cipher.DECRYPT_MODE, rk);

return cipher.doFinal(src);

}

public static String byte2hex(byte[] b)

{

String hs = "";

String stmp = "";

for (int n = 0; n b.length; n ++)

{

stmp = Integer.toHexString(b[n] 0xFF);

if (stmp.length() == 1)

hs += ("0" + stmp);

else

hs += stmp;

}

return hs.toUpperCase();

}

public static byte[] hex2byte(byte[] b)

{

if ((b.length % 2) != 0)

throw new IllegalArgumentException("长度不是偶数");

byte[] b2 = new byte[b.length / 2];

for (int n = 0; n b.length; n += 2)

{

String item = new String(b, n, 2);

b2[n/2] = (byte)Integer.parseInt(item, 16);

}

return b2;

}

//just for test

public static void main(String args[])

{

try

{

RSACrypto.generateKey();

String cipherText = RSACrypto.encrypt("asdfghjh");

System.out.println(cipherText);

String plainText = RSACrypto.decrypt(cipherText);

System.out.println(plainText);

}

catch(Exception e)

{

e.printStackTrace();

}

}

}

如何用java实现128位密钥的RSA算法

import javax.crypto.Cipher;

import sun.misc.BASE64Decoder;

import sun.misc.BASE64Encoder;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.security.Key;

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.SecureRandom;

public class RSA_Encrypt {

/** 指定加密算法为DESede */

private static String ALGORITHM = "RSA";

/** 指定key的大小 */

private static int KEYSIZE = 128;

/** 指定公钥存放文件 */

private static String PUBLIC_KEY_FILE = "PublicKey";

/** 指定私钥存放文件 */

private static String PRIVATE_KEY_FILE = "PrivateKey";

// private static String PUBLIC_KEY_FILE = "D://PublicKey.a";

// private static String PRIVATE_KEY_FILE = "D://PrivateKey.a";

/**

* 生成密钥对

*/

private static void generateKeyPair() throws Exception{

/** RSA算法要求有一个可信任的随机数源 */

SecureRandom sr = new SecureRandom();

/** 为RSA算法创建一个KeyPairGenerator对象 */

KeyPairGenerator kpg = KeyPairGenerator.getInstance(ALGORITHM);

/** 利用上面的随机数据源初始化这个KeyPairGenerator对象 */

kpg.initialize(KEYSIZE, sr);

/** 生成密匙对 */

KeyPair kp = kpg.generateKeyPair();

/** 得到公钥 */

Key publicKey = kp.getPublic();

/** 得到私钥 */

Key privateKey = kp.getPrivate();

/** 用对象流将生成的密钥写入文件 */

ObjectOutputStream oos1 = new ObjectOutputStream(new FileOutputStream(PUBLIC_KEY_FILE));

ObjectOutputStream oos2 = new ObjectOutputStream(new FileOutputStream(PRIVATE_KEY_FILE));

oos1.writeObject(publicKey);

oos2.writeObject(privateKey);

/** 清空缓存,关闭文件输出流 */

oos1.close();

oos2.close();

}

/**

* 加密方法

* source: 源数据

*/

public static String encrypt(String source) throws Exception{

generateKeyPair();

/** 将文件中的公钥对象读出 */

ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PUBLIC_KEY_FILE));

Key key = (Key) ois.readObject();

ois.close();

/** 得到Cipher对象来实现对源数据的RSA加密 */

Cipher cipher = Cipher.getInstance(ALGORITHM);

cipher.init(Cipher.ENCRYPT_MODE, key);

byte[] b = source.getBytes();

/** 执行加密操作 */

byte[] b1 = cipher.doFinal(b);

BASE64Encoder encoder = new BASE64Encoder();

return encoder.encode(b1);

}

/**

* 解密算法

* cryptograph:密文

*/

public static String decrypt(String cryptograph) throws Exception{

/** 将文件中的私钥对象读出 */

ObjectInputStream ois = new ObjectInputStream(new FileInputStream(PRIVATE_KEY_FILE));

Key key = (Key) ois.readObject();

/** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */

Cipher cipher = Cipher.getInstance(ALGORITHM);

cipher.init(Cipher.DECRYPT_MODE, key);

BASE64Decoder decoder = new BASE64Decoder();

byte[] b1 = decoder.decodeBuffer(cryptograph);

/** 执行解密操作 */

byte[] b = cipher.doFinal(b1);

return new String(b);

}

public static void main(String[] args) {

try {

String source = "Hello World!";//要加密的字符串

String cryptograph = encrypt(source);

System.out.println(cryptograph);

String target = decrypt(cryptograph);//解密密文

System.out.println(target);

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}//生成的密文

}

}

高分求java的RSA 和IDEA 加密解密算法

RSA算法非常简单,概述如下:

找两素数p和q

取n=p*q

取t=(p-1)*(q-1)

取任何一个数e,要求满足et并且e与t互素(就是最大公因数为1)

取d*e%t==1

这样最终得到三个数: n d e

设消息为数M (M n)

设c=(M**d)%n就得到了加密后的消息c

设m=(c**e)%n则 m == M,从而完成对c的解密。

注:**表示次方,上面两式中的d和e可以互换。

在对称加密中:

n d两个数构成公钥,可以告诉别人;

n e两个数构成私钥,e自己保留,不让任何人知道。

给别人发送的信息使用e加密,只要别人能用d解开就证明信息是由你发送的,构成了签名机制。

别人给你发送信息时使用d加密,这样只有拥有e的你能够对其解密。

rsa的安全性在于对于一个大数n,没有有效的方法能够将其分解

从而在已知n d的情况下无法获得e;同样在已知n e的情况下无法

求得d。

二实践

接下来我们来一个实践,看看实际的操作:

找两个素数:

p=47

q=59

这样

n=p*q=2773

t=(p-1)*(q-1)=2668

取e=63,满足et并且e和t互素

用perl简单穷举可以获得满主 e*d%t ==1的数d:

C:\Tempperl -e "foreach $i (1..9999){ print($i),last if $i*63%2668==1 }"

847

即d=847

最终我们获得关键的

n=2773

d=847

e=63

取消息M=244我们看看

加密:

c=M**d%n = 244**847%2773

用perl的大数计算来算一下:

C:\Tempperl -Mbigint -e "print 244**847%2773"

465

即用d对M加密后获得加密信息c=465

解密:

我们可以用e来对加密后的c进行解密,还原M:

m=c**e%n=465**63%2773 :

C:\Tempperl -Mbigint -e "print 465**63%2773"

244

即用e对c解密后获得m=244 , 该值和原始信息M相等。

三字符串加密

把上面的过程集成一下我们就能实现一个对字符串加密解密的示例了。

每次取字符串中的一个字符的ascii值作为M进行计算,其输出为加密后16进制

的数的字符串形式,按3字节表示,如01F

代码如下:

#!/usr/bin/perl -w

#RSA 计算过程学习程序编写的测试程序

#watercloud 2003-8-12

#

use strict;

use Math::BigInt;

my %RSA_CORE = (n=2773,e=63,d=847); #p=47,q=59

my $N=new Math::BigInt($RSA_CORE{n});

my $E=new Math::BigInt($RSA_CORE{e});

my $D=new Math::BigInt($RSA_CORE{d});

print "N=$N D=$D E=$E\n";

sub RSA_ENCRYPT

{

my $r_mess = shift @_;

my ($c,$i,$M,$C,$cmess);

for($i=0;$i length($$r_mess);$i++)

{

$c=ord(substr($$r_mess,$i,1));

$M=Math::BigInt-new($c);

$C=$M-copy(); $C-bmodpow($D,$N);

$c=sprintf "%03X",$C;

$cmess.=$c;

}

return \$cmess;

}

sub RSA_DECRYPT

{

my $r_mess = shift @_;

my ($c,$i,$M,$C,$dmess);

for($i=0;$i length($$r_mess);$i+=3)

{

$c=substr($$r_mess,$i,3);

$c=hex($c);

$M=Math::BigInt-new($c);

$C=$M-copy(); $C-bmodpow($E,$N);

$c=chr($C);

$dmess.=$c;

}

return \$dmess;

}

my $mess="RSA 娃哈哈哈~~~";

$mess=$ARGV[0] if @ARGV = 1;

print "原始串:",$mess,"\n";

my $r_cmess = RSA_ENCRYPT(\$mess);

print "加密串:",$$r_cmess,"\n";

my $r_dmess = RSA_DECRYPT($r_cmess);

print "解密串:",$$r_dmess,"\n";

#EOF

测试一下:

C:\Tempperl rsa-test.pl

N=2773 D=847 E=63

原始串:RSA 娃哈哈哈~~~

加密串:5CB6CD6BC58A7709470AA74A0AA74A0AA74A6C70A46C70A46C70A4

解密串:RSA 娃哈哈哈~~~

C:\Tempperl rsa-test.pl 安全焦点(xfocus)

N=2773 D=847 E=63

原始串:安全焦点(xfocus)

加密串:3393EC12F0A466E0AA9510D025D7BA0712DC3379F47D51C325D67B

解密串:安全焦点(xfocus)

四提高

前面已经提到,rsa的安全来源于n足够大,我们测试中使用的n是非常小的,根本不能保障安全性,

我们可以通过RSAKit、RSATool之类的工具获得足够大的N 及D E。

通过工具,我们获得1024位的N及D E来测试一下:

n=0x328C74784DF31119C526D18098EBEBB943B0032B599CEE13CC2BCE7B5FCD15F90B66EC3A85F5005D

BDCDED9BDFCB3C4C265AF164AD55884D8278F791C7A6BFDAD55EDBC4F017F9CCF1538D4C2013433B383B

47D80EC74B51276CA05B5D6346B9EE5AD2D7BE7ABFB36E37108DD60438941D2ED173CCA50E114705D7E2

BC511951

d=0x10001

e=0xE760A3804ACDE1E8E3D7DC0197F9CEF6282EF552E8CEBBB7434B01CB19A9D87A3106DD28C523C2995

4C5D86B36E943080E4919CA8CE08718C3B0930867A98F635EB9EA9200B25906D91B80A47B77324E66AFF2

C4D70D8B1C69C50A9D8B4B7A3C9EE05FFF3A16AFC023731D80634763DA1DCABE9861A4789BD782A592D2B

1965

设原始信息

M=0x11111111111122222222222233333333333

完成这么大数字的计算依赖于大数运算库,用perl来运算非常简单:

A) 用d对M进行加密如下:

c=M**d%n :

C:\Tempperl -Mbigint -e " $x=Math::BigInt-bmodpow(0x11111111111122222222222233

333333333, 0x10001, 0x328C74784DF31119C526D18098EBEBB943B0032B599CEE13CC2BCE7B5F

CD15F90B66EC3A85F5005DBDCDED9BDFCB3C4C265AF164AD55884D8278F791C7A6BFDAD55EDBC4F0

17F9CCF1538D4C2013433B383B47D80EC74B51276CA05B5D6346B9EE5AD2D7BE7ABFB36E37108DD6

0438941D2ED173CCA50E114705D7E2BC511951);print $x-as_hex"

0x17b287be418c69ecd7c39227ab681ac422fcc84bb35d8a632543b304de288a8d4434b73d2576bd

45692b007f3a2f7c5f5aa1d99ef3866af26a8e876712ed1d4cc4b293e26bc0a1dc67e247715caa6b

3028f9461a3b1533ec0cb476441465f10d8ad47452a12db0601c5e8beda686dd96d2acd59ea89b91

f1834580c3f6d90898

即用d对M加密后信息为:

c=0x17b287be418c69ecd7c39227ab681ac422fcc84bb35d8a632543b304de288a8d4434b73d2576bd

45692b007f3a2f7c5f5aa1d99ef3866af26a8e876712ed1d4cc4b293e26bc0a1dc67e247715caa6b

3028f9461a3b1533ec0cb476441465f10d8ad47452a12db0601c5e8beda686dd96d2acd59ea89b91

f1834580c3f6d90898

B) 用e对c进行解密如下:

m=c**e%n :

C:\Tempperl -Mbigint -e " $x=Math::BigInt-bmodpow(0x17b287be418c69ecd7c39227ab

681ac422fcc84bb35d8a632543b304de288a8d4434b73d2576bd45692b007f3a2f7c5f5aa1d99ef3

866af26a8e876712ed1d4cc4b293e26bc0a1dc67e247715caa6b3028f9461a3b1533ec0cb4764414

65f10d8ad47452a12db0601c5e8beda686dd96d2acd59ea89b91f1834580c3f6d90898, 0xE760A

3804ACDE1E8E3D7DC0197F9CEF6282EF552E8CEBBB7434B01CB19A9D87A3106DD28C523C29954C5D

86B36E943080E4919CA8CE08718C3B0930867A98F635EB9EA9200B25906D91B80A47B77324E66AFF

2C4D70D8B1C69C50A9D8B4B7A3C9EE05FFF3A16AFC023731D80634763DA1DCABE9861A4789BD782A

592D2B1965, 0x328C74784DF31119C526D18098EBEBB943B0032B599CEE13CC2BCE7B5FCD15F90

B66EC3A85F5005DBDCDED9BDFCB3C4C265AF164AD55884D8278F791C7A6BFDAD55EDBC4F017F9CCF

1538D4C2013433B383B47D80EC74B51276CA05B5D6346B9EE5AD2D7BE7ABFB36E37108DD60438941

D2ED173CCA50E114705D7E2BC511951);print $x-as_hex"

0x11111111111122222222222233333333333

(我的P4 1.6G的机器上计算了约5秒钟)

得到用e解密后的m=0x11111111111122222222222233333333333 == M

C) RSA通常的实现

RSA简洁幽雅,但计算速度比较慢,通常加密中并不是直接使用RSA 来对所有的信息进行加密,

最常见的情况是随机产生一个对称加密的密钥,然后使用对称加密算法对信息加密,之后用

RSA对刚才的加密密钥进行加密。

最后需要说明的是,当前小于1024位的N已经被证明是不安全的

自己使用中不要使用小于1024位的RSA,最好使用2048位的。

----------------------------------------------------------

一个简单的RSA算法实现JAVA源代码:

filename:RSA.java

/*

* Created on Mar 3, 2005

*

* TODO To change the template for this generated file go to

* Window - Preferences - Java - Code Style - Code Templates

*/

import java.math.BigInteger;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.FileWriter;

import java.io.FileReader;

import java.io.BufferedReader;

import java.util.StringTokenizer;

/**

* @author Steve

*

* TODO To change the template for this generated type comment go to

* Window - Preferences - Java - Code Style - Code Templates

*/

public class RSA {

/**

* BigInteger.ZERO

*/

private static final BigInteger ZERO = BigInteger.ZERO;

/**

* BigInteger.ONE

*/

private static final BigInteger ONE = BigInteger.ONE;

/**

* Pseudo BigInteger.TWO

*/

private static final BigInteger TWO = new BigInteger("2");

private BigInteger myKey;

private BigInteger myMod;

private int blockSize;

public RSA (BigInteger key, BigInteger n, int b) {

myKey = key;

myMod = n;

blockSize = b;

}

public void encodeFile (String filename) {

byte[] bytes = new byte[blockSize / 8 + 1];

byte[] temp;

int tempLen;

InputStream is = null;

FileWriter writer = null;

try {

is = new FileInputStream(filename);

writer = new FileWriter(filename + ".enc");

}

catch (FileNotFoundException e1){

System.out.println("File not found: " + filename);

}

catch (IOException e1){

System.out.println("File not found: " + filename + ".enc");

}

/**

* Write encoded message to 'filename'.enc

*/

try {

while ((tempLen = is.read(bytes, 1, blockSize / 8)) 0) {

for (int i = tempLen + 1; i bytes.length; ++i) {

bytes[i] = 0;

}

writer.write(encodeDecode(new BigInteger(bytes)) + " ");

}

}

catch (IOException e1) {

System.out.println("error writing to file");

}

/**

* Close input stream and file writer

*/

try {

is.close();

writer.close();

}

catch (IOException e1) {

System.out.println("Error closing file.");

}

}

public void decodeFile (String filename) {

FileReader reader = null;

OutputStream os = null;

try {

reader = new FileReader(filename);

os = new FileOutputStream(filename.replaceAll(".enc", ".dec"));

}

catch (FileNotFoundException e1) {

if (reader == null)

System.out.println("File not found: " + filename);

else

System.out.println("File not found: " + filename.replaceAll(".enc", "dec"));

}

BufferedReader br = new BufferedReader(reader);

int offset;

byte[] temp, toFile;

StringTokenizer st = null;

try {

while (br.ready()) {

st = new StringTokenizer(br.readLine());

while (st.hasMoreTokens()){

toFile = encodeDecode(new BigInteger(st.nextToken())).toByteArray();

System.out.println(toFile.length + " x " + (blockSize / 8));

if (toFile[0] == 0 toFile.length != (blockSize / 8)) {

temp = new byte[blockSize / 8];

offset = temp.length - toFile.length;

for (int i = toFile.length - 1; (i = 0) ((i + offset) = 0); --i) {

temp[i + offset] = toFile[i];

}

toFile = temp;

}

/*if (toFile.length != ((blockSize / 8) + 1)){

temp = new byte[(blockSize / 8) + 1];

System.out.println(toFile.length + " x " + temp.length);

for (int i = 1; i temp.length; i++) {

temp[i] = toFile[i - 1];

}

toFile = temp;

}

else

System.out.println(toFile.length + " " + ((blockSize / 8) + 1));*/

os.write(toFile);

}

}

}

catch (IOException e1) {

System.out.println("Something went wrong");

}

/**

* close data streams

*/

try {

os.close();

reader.close();

}

catch (IOException e1) {

System.out.println("Error closing file.");

}

}

/**

* Performs ttbase/tt^supttpow/tt/sup within the modular

* domain of ttmod/tt.

*

* @param base the base to be raised

* @param pow the power to which the base will be raisded

* @param mod the modular domain over which to perform this operation

* @return ttbase/tt^supttpow/tt/sup within the modular

* domain of ttmod/tt.

*/

public BigInteger encodeDecode(BigInteger base) {

BigInteger a = ONE;

BigInteger s = base;

BigInteger n = myKey;

while (!n.equals(ZERO)) {

if(!n.mod(TWO).equals(ZERO))

a = a.multiply(s).mod(myMod);

s = s.pow(2).mod(myMod);

n = n.divide(TWO);

}

return a;

}

}

在这里提供两个版本的RSA算法JAVA实现的代码下载:

1. 来自于 的RSA算法实现源代码包:

2. 来自于 的实现:

- 源代码包

- 编译好的jar包

另外关于RSA算法的php实现请参见文章:

php下的RSA算法实现

关于使用VB实现RSA算法的源代码下载(此程序采用了psc1算法来实现快速的RSA加密):

RSA加密的JavaScript实现:

求RSA算法JAVA实现源代码(带界面的)

import javax.crypto.Cipher;

import java.security.*;

import java.security.spec.RSAPublicKeySpec;

import java.security.spec.RSAPrivateKeySpec;

import java.security.spec.InvalidKeySpecException;

import java.security.interfaces.RSAPrivateKey;

import java.security.interfaces.RSAPublicKey;

import java.io.*;

import java.math.BigInteger;

/**

* RSA 工具类。提供加密,解密,生成密钥对等方法。

* 需要到下载bcprov-jdk14-123.jar。

* @author xiaoyusong

* mail: xiaoyusong@etang.com

* msn:xiao_yu_song@hotmail.com

* @since 2004-5-20

*

*/

public class RSAUtil {

/**

* 生成密钥对

* @return KeyPair

* @throws EncryptException

*/

public static KeyPair generateKeyPair() throws EncryptException {

try {

KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",

new org.bouncycastle.jce.provider.BouncyCastleProvider());

final int KEY_SIZE = 1024;//没什么好说的了,这个值关系到块加密的大小,可以更改,但是不要太大,否则效率会低

keyPairGen.initialize(KEY_SIZE, new SecureRandom());

KeyPair keyPair = keyPairGen.genKeyPair();

return keyPair;

} catch (Exception e) {

throw new EncryptException(e.getMessage());

}

}

/**

* 生成公钥

* @param modulus

* @param publicExponent

* @return RSAPublicKey

* @throws EncryptException

*/

public static RSAPublicKey generateRSAPublicKey(byte[] modulus, byte[] publicExponent) throws EncryptException {

KeyFactory keyFac = null;

try {

keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());

} catch (NoSuchAlgorithmException ex) {

throw new EncryptException(ex.getMessage());

}

RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(modulus), new BigInteger(publicExponent));

try {

return (RSAPublicKey) keyFac.generatePublic(pubKeySpec);

} catch (InvalidKeySpecException ex) {

throw new EncryptException(ex.getMessage());

}

}

/**

* 生成私钥

* @param modulus

* @param privateExponent

* @return RSAPrivateKey

* @throws EncryptException

*/

public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus, byte[] privateExponent) throws EncryptException {

KeyFactory keyFac = null;

try {

keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());

} catch (NoSuchAlgorithmException ex) {

throw new EncryptException(ex.getMessage());

}

RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(modulus), new BigInteger(privateExponent));

try {

return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);

} catch (InvalidKeySpecException ex) {

throw new EncryptException(ex.getMessage());

}

}

/**

* 加密

* @param key 加密的密钥

* @param data 待加密的明文数据

* @return 加密后的数据

* @throws EncryptException

*/

public static byte[] encrypt(Key key, byte[] data) throws EncryptException {

try {

Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());

cipher.init(Cipher.ENCRYPT_MODE, key);

int blockSize = cipher.getBlockSize();//获得加密块大小,如:加密前数据为128个byte,而key_size=1024 加密块大小为127 byte,加密后为128个byte;因此共有2个加密块,第一个127 byte第二个为1个byte

int outputSize = cipher.getOutputSize(data.length);//获得加密块加密后块大小

int leavedSize = data.length % blockSize;

int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize;

byte[] raw = new byte[outputSize * blocksSize];

int i = 0;

while (data.length - i * blockSize 0) {

if (data.length - i * blockSize blockSize)

cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize);

else

cipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize);

//这里面doUpdate方法不可用,查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte[]放到ByteArrayOutputStream中,而最后doFinal的时候才将所有的byte[]进行加密,可是到了此时加密块大小很可能已经超出了OutputSize所以只好用dofinal方法。

i++;

}

return raw;

} catch (Exception e) {

throw new EncryptException(e.getMessage());

}

}

/**

* 解密

* @param key 解密的密钥

* @param raw 已经加密的数据

* @return 解密后的明文

* @throws EncryptException

*/

public static byte[] decrypt(Key key, byte[] raw) throws EncryptException {

try {

Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider());

cipher.init(cipher.DECRYPT_MODE, key);

int blockSize = cipher.getBlockSize();

ByteArrayOutputStream bout = new ByteArrayOutputStream(64);

int j = 0;

while (raw.length - j * blockSize 0) {

bout.write(cipher.doFinal(raw, j * blockSize, blockSize));

j++;

}

return bout.toByteArray();

} catch (Exception e) {

throw new EncryptException(e.getMessage());

}

}

/**

*

* @param args

* @throws Exception

*/

public static void main(String[] args) throws Exception {

File file = new File("test.html");

FileInputStream in = new FileInputStream(file);

ByteArrayOutputStream bout = new ByteArrayOutputStream();

byte[] tmpbuf = new byte[1024];

int count = 0;

while ((count = in.read(tmpbuf)) != -1) {

bout.write(tmpbuf, 0, count);

tmpbuf = new byte[1024];

}

in.close();

byte[] orgData = bout.toByteArray();

KeyPair keyPair = RSAUtil.generateKeyPair();

RSAPublicKey pubKey = (RSAPublicKey) keyPair.getPublic();

RSAPrivateKey priKey = (RSAPrivateKey) keyPair.getPrivate();

byte[] pubModBytes = pubKey.getModulus().toByteArray();

byte[] pubPubExpBytes = pubKey.getPublicExponent().toByteArray();

byte[] priModBytes = priKey.getModulus().toByteArray();

byte[] priPriExpBytes = priKey.getPrivateExponent().toByteArray();

RSAPublicKey recoveryPubKey = RSAUtil.generateRSAPublicKey(pubModBytes,pubPubExpBytes);

RSAPrivateKey recoveryPriKey = RSAUtil.generateRSAPrivateKey(priModBytes,priPriExpBytes);

byte[] raw = RSAUtil.encrypt(priKey, orgData);

file = new File("encrypt_result.dat");

OutputStream out = new FileOutputStream(file);

out.write(raw);

out.close();

byte[] data = RSAUtil.decrypt(recoveryPubKey, raw);

file = new File("decrypt_result.html");

out = new FileOutputStream(file);

out.write(data);

out.flush();

out.close();

}

}

这个行吧

再参考这个吧


本文标题:rsa算法代码java,rsa算法代码实现
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