Java/IOS通用异或加解密字符串

1、Java的异或加解密算法

在使用异或加解密时，加密和解密的密钥必须保持相同，否则解密时无法恢复为原来的内容。

 [java] 

public class XOREncryptAndDecrypt {

    //密钥 加解密的密钥必须相同 可自定义
    private static final String secretKey ="abcdefghijklmnopqrstuvwxyz";

    /**
     * 字符串加密
     * @param plainText 要加密的字符串
     * @return 加密后的字符串
     */
    public static String encrypt(String plainText){
         String encryption = "";
         try {
             plainText =  new String(plainText.getBytes("UTF-8"),"iso-8859-1");
            } catch (Exception e) {
            }
         char[] cipher=new char[plainText.length()];
         for(int i=0,j=0;i<plainText.length();i++,j++){
             if(j==secretKey.length())
                 j=0;
             cipher[i]=(char) (plainText.charAt(i)^secretKey.charAt(j));
             String strCipher= Integer.toHexString(cipher[i]);
             if(strCipher.length() == 1){
                 encryption+="0"+strCipher;
             }else{
                 encryption+=strCipher;
             }
         }
         return encryption;
     }

    /**
     * 解密字符串
     * @param encryption 要解密的字符串
     * @return 解密后的字符串
     */
    public static String decrypt(String encryption) {
         char[] decryption=new char[encryption.length()/2];
         for(int i=0,j=0;i<encryption.length()/2;i++,j++){
             if(j==secretKey.length())
                 j=0;
             char n=(char)(int)Integer.valueOf(encryption.substring(i*2,i*2+2),16);
             decryption[i]=(char)(n^secretKey.charAt(j));
         }
         String decoding="";
         try {
             decoding = new String(String.valueOf(decryption).getBytes("iso-8859-1"),"UTF-8");
                } catch (Exception e) {
            }
         return decoding;
     }

    /**
     * @param args
     */
    public static void main(String[] args) {
        String name="你好";
         String tem=XOREncryptAndDecrypt.encrypt(name);
         System.out.println(tem);
         System.out.println(XOREncryptAndDecrypt.decrypt(tem));

    }

}

2、IOS加解密算法

 在使用异或加解密时，加密和解密的密钥必须保持相同，否则解密时无法恢复为原来的内容。如果想在iOS与Java中通用，必须保持Java与IOS中的密钥一致。

1）.h文件内容

 [objc] 

#import <Foundation/Foundation.h>

@interface XOREncryptAndDecrypt : NSObject

/**
 *  字符串加密
 *
 *  @param plainText 要加密的字符串
 *
 *  @return 加密后的字符串
 */
+ (NSString *)encryptForPlainText:(NSString *)plainText;

/**
 *  解密字符串
 *
 *  @param encryption 要解密的字符串
 *
 *  @return 要解密的字符串 如果不为加密字符则返回原字符串
 */
+ (NSString *)decryptForEncryption:(NSString *)encryption;

@end

2）.m文件内容

 [objc] 

#import "XOREncryptAndDecrypt.h"
@implementation XOREncryptAndDecrypt
static NSString *secretKey =@"abcdefghijklmnopqrstuvwxyz"; ///<密钥 加解密的密钥必须相同 可自定义
#pragma mark 加密字符串
+ (NSString *)encryptForPlainText:(NSString *)plainText
{
//保存加密后的字符
NSMutableString *encryption=[NSMutableString string];
//编码转换后的字符串 UTF_8->iso-8859-1
NSString *encoding=[[NSString alloc]initWithData:[plainText dataUsingEncoding:NSUTF8StringEncoding] encoding:NSISOLatin1StringEncoding];
for(int i=0,j=0;i<encoding.length;i++,j++){
if(j==secretKey.length){
            j=0;
        }
//异或后的字符
char cipher=(char)([encoding characterAtIndex:i]^[secretKey characterAtIndex:j]);
//NSLog(@"%c转成16进制的字符串：%@,%@",cipher,[NSString stringWithFormat:@"%hhx",cipher],[NSString stringWithFormat:@"%x",cipher&0xff]);
//转成16进制形式的字符串 x8b转成8b字符串
NSString *strCipher= [NSString stringWithFormat:@"%hhx",cipher];
if(strCipher.length == 1){
            [encryption appendFormat:@"0%@",strCipher];
        }else{
            [encryption appendString:strCipher];
        }
    }
return encryption;
}
#pragma mark 解密 如果不为加密字符则返回原字符
+ (NSString *)decryptForEncryption:(NSString *)encryption {
//保存解密后的字符
NSMutableString *decryption=[NSMutableString string];
//解码字符
NSString *decoding=nil;
for(int i=0,j=0;i<encryption.length/2;i++,j++){
if(j==secretKey.length){
            j=0;
        }
//截取16进制形式的字符串 x8b中的8b
NSString *tem=[encryption substringWithRange:NSMakeRange(i*2, 2)];
char  *endptr;
//把16进制形式的字符串转为字符
char n=(char)(int)strtoul([tem UTF8String],&endptr,16);
//判断是否为加密字符
if (n==''&&*endptr!='') {
            [decryption setString:@""];
break;
        }
        [decryption appendFormat:@"%c",(char)(n^[secretKey characterAtIndex:j])];
    }
if (![decryption isEqualToString:@""]) {
//编码后的字符串 iso-8859-1 -> UTF_8
        decoding=[[NSString alloc]initWithData:[[decryption copy] dataUsingEncoding:NSISOLatin1StringEncoding] encoding:NSUTF8StringEncoding];
    }
if (decoding==nil) {
        decoding=encryption;
    }
return decoding;
}
@end