使用DES加解密

这里使用框架提供的des加解密库： 首先引入头文件 #import <CommonCrypto/CommonCryptor.h>

主要的加解密函数如下:

/*字符串加密

 *参数

 *plainText : 加密明文

 *key        : 密钥 64位

 */

+ (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));

    Byte iv[] = {1,2,3,4,5,6,7,8};

    size_t numBytesEncrypted = 0;

    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,

                                          kCCOptionPKCS7Padding,

                                          [key UTF8String], kCCKeySizeDES,

                                          iv,

                                          textBytes, dataLength,

                                          buffer, 1024,

                                          &numBytesEncrypted);

    if (cryptStatus == kCCSuccess) {

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

        

        ciphertext = [[[NSString alloc] initWithData:[GTMBase64 encodeData:data] encoding:NSUTF8StringEncoding] autorelease];

    }

    return ciphertext;

}

 

//解密

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

{

    NSData* cipherData = [GTMBase64 decodeString:cipherText];

    unsigned char buffer[1024];

    memset(buffer, 0, sizeof(char));

    size_t numBytesDecrypted = 0;

    Byte iv[] = {1,2,3,4,5,6,7,8};

    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, 

                                          kCCAlgorithmDES, 

                                          kCCOptionPKCS7Padding, 

                                          [key UTF8String], 

                                          kCCKeySizeDES, 

                                          iv, 

                                          [cipherData bytes], 

                                          [cipherData length], 

                                          buffer, 

                                          1024, 

                                          &numBytesDecrypted);

    NSString* plainText = nil;

    if (cryptStatus == kCCSuccess) {

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

        plainText = [[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease];

    }

    return plainText;

}

注：函数中使用到了Base64的编解码，请到下面地址中下载相应库
http://www.jguoer.com/blog/wp-content/uploads/2010/1/base64.zip