IOS常用加密DES

NSString+DES.h

//

//  NSString+DES.h

//  haochang

//

//  Created by Administrator on 14-4-15.

//  Copyright (c) 2014年 Administrator. All rights reserved.

//



#import <Foundation/Foundation.h>



@interface NSString (DES)



//加密

+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key;

//解密

+(NSString *) decryptUseDES:(NSString *)plainText key:(NSString *)key;



@end

NSString+DES.m

//

//  NSString+DES.m

//  haochang

//

//  Created by Administrator on 14-4-15.

//  Copyright (c) 2014年 Administrator. All rights reserved.

//



#import "NSString+DES.h"

#import <CommonCrypto/CommonCrypto.h>



@implementation NSString (DES)



//加密

+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key;

{

    NSString *ciphertext = nil;

    const char *textBytes = [plainText UTF8String];

    NSUInteger dataLength = [plainText length];

    unsigned char buffer[1024];

    memset(buffer, 0, sizeof(char));

    size_t numBytesEncrypted = 0;

    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,

                                          kCCOptionPKCS7Padding,

                                          [key UTF8String], kCCKeySizeDES,

                                          NULL,

                                          textBytes, dataLength,

                                          buffer, 1024,

                                          &numBytesEncrypted);

    if (cryptStatus == kCCSuccess) {

        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];

        ciphertext = [self dataTohexString:data];

    }

    

    return ciphertext;

}



//解密

+(NSString *) decryptUseDES:(NSString *)plainText key:(NSString *)key

{

    NSString *cleartext = nil;

    NSData *textData = [self hexStringToData:plainText];

    NSUInteger dataLength = [textData length];

    unsigned char buffer[1024];

    memset(buffer, 0, sizeof(char));

    size_t numBytesEncrypted = 0;

    

    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES,kCCOptionPKCS7Padding,

                                          [key UTF8String], kCCKeySizeDES,

                                          NULL,

                                          [textData bytes]  , dataLength,

                                          buffer, 1024,

                                          &numBytesEncrypted);

    if (cryptStatus == kCCSuccess) {

        //NSLog(@"DES解密成功");

        NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];

        cleartext = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

    }else{

        //NSLog(@"DES解密失败");

    }

    return cleartext;

}



+ (NSString *)dataTohexString:(NSData*)data

{

    Byte *bytes = (Byte *)[data bytes];

    NSString *hexStr=@"";

    for(int i=0;i<[data length];i++)

    {

        NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];//16进制数

        if([newHexStr length]==1)

            hexStr = [NSString  stringWithFormat:@"%@0%@",hexStr,newHexStr];

        else

            hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];

    }

    return hexStr;

}





+ (NSData*)hexStringToData:(NSString*)hexString

{

    //NSString *hexString = @"3e435fab9c34891f"; //16进制字符串

    int j=0;

    Byte bytes[hexString.length];  ///3ds key的Byte 数组， 128位

    for(int i=0;i<[hexString length];i++)

    {

        int int_ch;  /// 两位16进制数转化后的10进制数

        

        unichar hex_char1 = [hexString characterAtIndex:i]; ////两位16进制数中的第一位(高位*16)

        int int_ch1;

        if(hex_char1 >= '0' && hex_char1 <='9')

            int_ch1 = (hex_char1-48)*16;   //// 0 的Ascll - 48

        else if(hex_char1 >= 'A' && hex_char1 <='F')

            int_ch1 = (hex_char1-55)*16; //// A 的Ascll - 65

        else

            int_ch1 = (hex_char1-87)*16; //// a 的Ascll - 97

        i++;

        

        unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)

        int int_ch2;

        if(hex_char2 >= '0' && hex_char2 <='9')

            int_ch2 = (hex_char2-48); //// 0 的Ascll - 48

        else if(hex_char1 >= 'A' && hex_char1 <='F')

            int_ch2 = hex_char2-55; //// A 的Ascll - 65

        else

            int_ch2 = hex_char2-87; //// a 的Ascll - 97

        

        int_ch = int_ch1+int_ch2;

        //NSLog(@"int_ch=%x",int_ch);

        bytes[j] = int_ch;  ///将转化后的数放入Byte数组里

        j++;

    }

    //    NSData *newData = [[NSData alloc] initWithBytes:bytes length:j];

    NSData *newData = [[NSData alloc] initWithBytes:bytes length:j];

    //NSLog(@"newData=%@",newData);

    return newData;

}



@end