本文目录一览:
- 1、java对文件编写明文密文问题
- 2、关于Java的AES加密问题
- 3、求java大佬指点一、 编写一个Java应用程序:Ex3_1.java,对下面的明文进行加密处理并输出:
- 4、写一个java加密程序
- 5、JAVA简单文件加密 求JAVA源代码
- 6、关于java直接进行密文运算的问题
java对文件编写明文密文问题
看样子你是想把输入的字母 根据ALPHABET 码字表 换成 REPLACEMENT 里的内容。比如输入了“fuck”,那么转换以后差不多是 “rfdw” 对吧。如果这样的话。你的问题错在
for(int i = 0;iline.length();i++) {
for(int j = 0;jALPHABET.length();j++) {
if(line.charAt(i) == ALPHABET.charAt(j) ) {s
ALPHABET.charAt(i) = REPLACEMENT.charAt(j);//这里错了。目的是要替换line的第i个字符 } else {
}
}
可以改成:
String A="";
for(int i = 0;iline.length();i++) {
int x = ALPHABET.indexOf(line.charAt(i));
if(x 0)
A+= REPLACEMENT.charAt(i);
else
A+= line.charAt(i);
}
return A;
关于Java的AES加密问题
使用AES加密时,当密钥大于128时,代码会抛出java.security.InvalidKeyException: Illegal key size or default parameters
Illegal key size or default parameters是指密钥长度是受限制的,java运行时环境读到的是受限的policy文件。文件位于${java_home}/jre/lib/security
这种限制是因为美国对软件出口的控制。
解决办法:
去掉这种限制需要下载Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files.网址如下。
下载包的readme.txt 有安装说明。就是替换${java_home}/jre/lib/security/ 下面的local_policy.jar和US_export_policy.jar
jdk 5:
求java大佬指点一、 编写一个Java应用程序:Ex3_1.java,对下面的明文进行加密处理并输出:
你好提问者:
如果解决了你的问题,请采纳,若有疑问,请追问,谢谢!
package com.gc.action.baiduTest;
public class ShowHello {
/**
* 加密:大写+5 数字+3 其他不变
* @param str
*/
public static void mdm(String str){
System.out.println("加密前"+str);
StringBuffer sb =new StringBuffer();
for (int i = 0; i str.length(); i++) {
char ch = str.charAt(i);
if(ch=65 ch=85){//A:65 U:85
ch = (char) (ch+5);
sb.append(ch);
}else if (ch85 ch =90) {
ch = (char) (ch-21);
sb.append(ch);
}else if(ch=48 ch=54){
ch =(char) (ch+3);
sb.append(ch);
}else if(ch54 ch=57){
ch =(char) (ch-7);
sb.append(ch);
}else{
sb.append(ch);
}
}
System.out.println("加密后"+sb);
}
public static void main(String[] args) {
String str ="ABC_ 0123 _XZY_ 789";//OPERATION OVERLORD: THE NORMANDY LANDINGS WILL TAKE PLACE ON JUNE 6th ,1944,AT 6:30
mdm(str);
}
}
结果:
加密前ABC_ 0123 _XZY_ 789
加密后FGH_ 3456 _CED_ 012
----------------------------
加密前OPERATION OVERLORD: THE NORMANDY LANDINGS WILL TAKE PLACE ON JUNE 6th ,1944,AT 6:30
加密后TUJWFYNTS TAJWQTWI: YMJ STWRFSID QFSINSLX BNQQ YFPJ UQFHJ TS OZSJ 9th ,4277,FY 9:63
写一个java加密程序
/**
* SHA-1加密函数
*
*
*/
public class SsytemSha1 {
private final int[] abcde = {
0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0
};
// 摘要数据存储数组
private int[] digestInt = new int[5];
// 计算过程中的临时数据存储数组
private int[] tmpData = new int[80];
// 计算sha-1摘要
private int process_input_bytes(byte[] bytedata) {
// 初试化常量
System.arraycopy(abcde, 0, digestInt, 0, abcde.length);
// 格式化输入字节数组,补10及长度数据
byte[] newbyte = byteArrayFormatData(bytedata);
// 获取数据摘要计算的数据单元个数
int MCount = newbyte.length / 64;
// 循环对每个数据单元进行摘要计算
for (int pos = 0; pos MCount; pos++) {
// 将每个单元的数据转换成16个整型数据,并保存到tmpData的前16个数组元素中
for (int j = 0; j 16; j++) {
tmpData[j] = byteArrayToInt(newbyte, (pos * 64) + (j * 4));
}
// 摘要计算函数
encrypt();
}
return 20;
}
// 格式化输入字节数组格式
private byte[] byteArrayFormatData(byte[] bytedata) {
// 补0数量
int zeros = 0;
// 补位后总位数
int size = 0;
// 原始数据长度
int n = bytedata.length;
// 模64后的剩余位数
int m = n % 64;
// 计算添加0的个数以及添加10后的总长度
if (m 56) {
zeros = 55 - m;
size = n - m + 64;
} else if (m == 56) {
zeros = 63;
size = n + 8 + 64;
} else {
zeros = 63 - m + 56;
size = (n + 64) - m + 64;
}
// 补位后生成的新数组内容
byte[] newbyte = new byte[size];
// 复制数组的前面部分
System.arraycopy(bytedata, 0, newbyte, 0, n);
// 获得数组Append数据元素的位置
int l = n;
// 补1操作
newbyte[l++] = (byte) 0x80;
// 补0操作
for (int i = 0; i zeros; i++) {
newbyte[l++] = (byte) 0x00;
}
// 计算数据长度,补数据长度位共8字节,长整型
long N = (long) n * 8;
byte h8 = (byte) (N 0xFF);
byte h7 = (byte) ((N 8) 0xFF);
byte h6 = (byte) ((N 16) 0xFF);
byte h5 = (byte) ((N 24) 0xFF);
byte h4 = (byte) ((N 32) 0xFF);
byte h3 = (byte) ((N 40) 0xFF);
byte h2 = (byte) ((N 48) 0xFF);
byte h1 = (byte) (N 56);
newbyte[l++] = h1;
newbyte[l++] = h2;
newbyte[l++] = h3;
newbyte[l++] = h4;
newbyte[l++] = h5;
newbyte[l++] = h6;
newbyte[l++] = h7;
newbyte[l++] = h8;
return newbyte;
}
private int f1(int x, int y, int z) {
return (x y) | (~x z);
}
private int f2(int x, int y, int z) {
return x ^ y ^ z;
}
private int f3(int x, int y, int z) {
return (x y) | (x z) | (y z);
}
private int f4(int x, int y) {
return (x y) | x (32 - y);
}
// 单元摘要计算函数
private void encrypt() {
for (int i = 16; i = 79; i++) {
tmpData[i] = f4(tmpData[i - 3] ^ tmpData[i - 8] ^ tmpData[i - 14] ^
tmpData[i - 16], 1);
}
int[] tmpabcde = new int[5];
for (int i1 = 0; i1 tmpabcde.length; i1++) {
tmpabcde[i1] = digestInt[i1];
}
for (int j = 0; j = 19; j++) {
int tmp = f4(tmpabcde[0], 5) +
f1(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
tmpData[j] + 0x5a827999;
tmpabcde[4] = tmpabcde[3];
tmpabcde[3] = tmpabcde[2];
tmpabcde[2] = f4(tmpabcde[1], 30);
tmpabcde[1] = tmpabcde[0];
tmpabcde[0] = tmp;
}
for (int k = 20; k = 39; k++) {
int tmp = f4(tmpabcde[0], 5) +
f2(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
tmpData[k] + 0x6ed9eba1;
tmpabcde[4] = tmpabcde[3];
tmpabcde[3] = tmpabcde[2];
tmpabcde[2] = f4(tmpabcde[1], 30);
tmpabcde[1] = tmpabcde[0];
tmpabcde[0] = tmp;
}
for (int l = 40; l = 59; l++) {
int tmp = f4(tmpabcde[0], 5) +
f3(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
tmpData[l] + 0x8f1bbcdc;
tmpabcde[4] = tmpabcde[3];
tmpabcde[3] = tmpabcde[2];
tmpabcde[2] = f4(tmpabcde[1], 30);
tmpabcde[1] = tmpabcde[0];
tmpabcde[0] = tmp;
}
for (int m = 60; m = 79; m++) {
int tmp = f4(tmpabcde[0], 5) +
f2(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
tmpData[m] + 0xca62c1d6;
tmpabcde[4] = tmpabcde[3];
tmpabcde[3] = tmpabcde[2];
tmpabcde[2] = f4(tmpabcde[1], 30);
tmpabcde[1] = tmpabcde[0];
tmpabcde[0] = tmp;
}
for (int i2 = 0; i2 tmpabcde.length; i2++) {
digestInt[i2] = digestInt[i2] + tmpabcde[i2];
}
for (int n = 0; n tmpData.length; n++) {
tmpData[n] = 0;
}
}
// 4字节数组转换为整数
private int byteArrayToInt(byte[] bytedata, int i) {
return ((bytedata[i] 0xff) 24) | ((bytedata[i + 1] 0xff) 16) |
((bytedata[i + 2] 0xff) 8) | (bytedata[i + 3] 0xff);
}
// 整数转换为4字节数组
private void intToByteArray(int intValue, byte[] byteData, int i) {
byteData[i] = (byte) (intValue 24);
byteData[i + 1] = (byte) (intValue 16);
byteData[i + 2] = (byte) (intValue 8);
byteData[i + 3] = (byte) intValue;
}
// 将字节转换为十六进制字符串
private static String byteToHexString(byte ib) {
char[] Digit = {
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C',
'D', 'E', 'F'
};
char[] ob = new char[2];
ob[0] = Digit[(ib 4) 0X0F];
ob[1] = Digit[ib 0X0F];
String s = new String(ob);
return s;
}
// 将字节数组转换为十六进制字符串
private static String byteArrayToHexString(byte[] bytearray) {
String strDigest = "";
for (int i = 0; i bytearray.length; i++) {
strDigest += byteToHexString(bytearray[i]);
}
return strDigest;
}
// 计算sha-1摘要,返回相应的字节数组
public byte[] getDigestOfBytes(byte[] byteData) {
process_input_bytes(byteData);
byte[] digest = new byte[20];
for (int i = 0; i digestInt.length; i++) {
intToByteArray(digestInt[i], digest, i * 4);
}
return digest;
}
// 计算sha-1摘要,返回相应的十六进制字符串
public String getDigestOfString(byte[] byteData) {
return byteArrayToHexString(getDigestOfBytes(byteData));
}
public static void main(String[] args) { //测试通过
String data = "123";
String digest = new SsytemSha1().getDigestOfString(data.getBytes());
}
}
JAVA简单文件加密 求JAVA源代码
md5加密:
package com.ncs.pki.util;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class MD5Test {
private static MessageDigest digest = null;
public synchronized static final String hash(String data) {
if (digest == null) {
try {
digest = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException nsae) {
System.err.println(
"Failed to load the MD5 MessageDigest. "
+ "Jive will be unable to function normally.");
nsae.printStackTrace();
}
}
// Now, compute hash.
digest.update(data.getBytes());
return encodeHex(digest.digest());
}
public static final String encodeHex(byte[] bytes) {
StringBuffer buf = new StringBuffer(bytes.length * 2);
int i;
for (i = 0; i bytes.length; i++) {
if (((int) bytes[i] 0xff) 0x10) {
buf.append("0");
}
buf.append(Long.toString((int) bytes[i] 0xff, 16));
}
return buf.toString();
}
public static String test(){
return null;
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println(MD5Test.hash("123456"));
}
}
3des加密:
package com.ncs.pki.util;
import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class DesEncrypt {
/**
*
* 使用DES加密与解密,可对byte[],String类型进行加密与解密 密文可使用String,byte[]存储.
*
* 方法: void getKey(String strKey)从strKey的字条生成一个Key
*
* String getEncString(String strMing)对strMing进行加密,返回String密文 String
* getDesString(String strMi)对strMin进行解密,返回String明文
*
*byte[] getEncCode(byte[] byteS)byte[]型的加密 byte[] getDesCode(byte[]
* byteD)byte[]型的解密
*/
Key key;
/**
* 根据参数生成KEY
*
* @param strKey
*/
public void getKey(String strKey) {
try {
KeyGenerator _generator = KeyGenerator.getInstance("DES");
_generator.init(new SecureRandom(strKey.getBytes()));
this.key = _generator.generateKey();
_generator = null;
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 加密String明文输入,String密文输出
*
* @param strMing
* @return
*/
public String getEncString(String strMing) {
byte[] byteMi = null;
byte[] byteMing = null;
String strMi = "";
BASE64Encoder base64en = new BASE64Encoder();
try {
byteMing = strMing.getBytes("UTF8");
byteMi = this.getEncCode(byteMing);
strMi = base64en.encode(byteMi);
} catch (Exception e) {
e.printStackTrace();
} finally {
base64en = null;
byteMing = null;
byteMi = null;
}
return strMi;
}
/**
* 解密 以String密文输入,String明文输出
*
* @param strMi
* @return
*/
public String getDesString(String strMi) {
BASE64Decoder base64De = new BASE64Decoder();
byte[] byteMing = null;
byte[] byteMi = null;
String strMing = "";
try {
byteMi = base64De.decodeBuffer(strMi);
byteMing = this.getDesCode(byteMi);
strMing = new String(byteMing, "UTF8");
} catch (Exception e) {
e.printStackTrace();
} finally {
base64De = null;
byteMing = null;
byteMi = null;
}
return strMing;
}
/**
* 加密以byte[]明文输入,byte[]密文输出
*
* @param byteS
* @return
*/
private byte[] getEncCode(byte[] byteS) {
byte[] byteFina = null;
Cipher cipher;
try {
cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, key);
byteFina = cipher.doFinal(byteS);
} catch (Exception e) {
e.printStackTrace();
} finally {
cipher = null;
}
return byteFina;
}
/**
* 解密以byte[]密文输入,以byte[]明文输出
*
* @param byteD
* @return
*/
private byte[] getDesCode(byte[] byteD) {
Cipher cipher;
byte[] byteFina = null;
try {
cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, key);
byteFina = cipher.doFinal(byteD);
} catch (Exception e) {
e.printStackTrace();
} finally {
cipher = null;
}
return byteFina;
}
public static void main(String[] args) {
System.out.println("des demo");
DesEncrypt des = new DesEncrypt();// 实例化一个对像
des.getKey("MYKEY");// 生成密匙
System.out.println("key=MYKEY");
String strEnc = des.getEncString("111111");// 加密字符串,返回String的密文
System.out.println("密文=" + strEnc);
String strDes = des.getDesString(strEnc);// 把String 类型的密文解密
System.out.println("明文=" + strDes);
}
}
关于java直接进行密文运算的问题
你说的要么很先进,要么就是乱套概念,没事干啥这么做?这是小问题? 乘法根本跟字节没关系,也不等于RSA运算,非要这么做得正确结果只能改为enc(12*12)。