EncryptTool

EncryptTool.h

//
//  Des.h
//  HungryBear
//
//  Created by Bruce Yang on 12-5-26.
//  Copyright (c) 2012年 EricGameStudio. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonCryptor.h>
#import "GTMBase64.h"

@interface EncryptTool : NSObject {
    
}

+(EncryptTool*) et;

+(NSString*) parseByte2HexString:(Byte*)bytes;

+(NSString*) parseByteArray2HexString:(Byte[])bytes;

-(id) init;

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

-(NSString*) decryptUseDES:(NSString*)cipherText key:(NSString*)key;

@end

EncryptTool.mm

//
//  Des.mm
//  HungryBear
//
//  Created by Bruce Yang on 12-5-26.
//  Copyright (c) 2012年 EricGameStudio. All rights reserved.
//

#import "EncryptTool.h"

@implementation EncryptTool

static Byte _iv_[] = {1, 2, 3, 4, 5, 6, 7, 8};

+(EncryptTool*) et {
    return [[[self alloc] init] autorelease];
}

+(NSString*) parseByte2HexString:(Byte*) bytes {
    NSMutableString *hexStr = [[NSMutableString alloc]init];
    int i = 0;
    if(bytes) {
        while (bytes[i] != '\0') {
            NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];///16进制数
            if([hexByte length]==1) {
                [hexStr appendFormat:@"0%@", hexByte];
            } else {
                [hexStr appendFormat:@"%@", hexByte];
            }
            i ++;
        }
    }
    NSLog(@"bytes 的16进制数为:%@",hexStr);
    return hexStr;
}


+(NSString*) parseByteArray2HexString:(Byte[]) bytes {
    NSMutableString *hexStr = [[NSMutableString alloc]init];
    int i = 0;
    if(bytes) {
        while (bytes[i] != '\0') {
            NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];///16进制数
            if([hexByte length]==1) {
                [hexStr appendFormat:@"0%@", hexByte];
            } else {
                [hexStr appendFormat:@"%@", hexByte];
            }
            i ++;
        }
    }
    NSLog(@"bytes 的16进制数为:%@",hexStr);
    return hexStr;
}


-(id) init {
    if((self = [super init])) {
        
    }
    return self;
}


-(NSString*) encryptUseDES:(NSString*)plainText key:(NSString*)key {
    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, 
                                          _iv_, 
                                          textBytes, 
                                          dataLength, 
                                          buffer, 
                                          1024, 
                                          &numBytesEncrypted);
    
    NSString* cipherText = nil;
    if (cryptStatus == kCCSuccess) {
        NSData* data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
        cipherText = [GTMBase64 stringByEncodingData:data];
    }
    return cipherText;
}


-(NSString*) decryptUseDES:(NSString*)cipherText key:(NSString*)key {
    NSData* cipherData = [GTMBase64 decodeString:cipherText];
    
    // 8kB~
    unsigned char buffer[8196];
    memset(buffer, 0, sizeof(char));
    size_t numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, 
                                          kCCAlgorithmDES, 
                                          kCCOptionPKCS7Padding, 
                                          [key UTF8String], 
                                          kCCKeySizeDES, 
                                          _iv_, 
                                          [cipherData bytes], 
                                          [cipherData length], 
                                          buffer, 
                                          8196, 
                                          &numBytesDecrypted);
    NSString* plainText = nil;
    
    /**
     * 2012.05.27.09.34,中间遇到一个问题，
     * 查看了一下返回的状态码，皆是因为 buffer 的尺寸过小所致
     * 最开始 buffer 的长度是 1024~
     */
//    NSLog(@"%d", cryptStatus);
    
    if (cryptStatus == kCCSuccess) {
        NSData* data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesDecrypted];
        plainText = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];
    }
    return plainText;
}


@end