iOS DES 加密转base64

//用法 加密转base 64
NSString *str = [self base64StringFromText:@"qingjoin" withKey:@"key"];

//转base 64 解密
 NSString *stred = [self textFromBase64String:str withKey:@"key"];

//文本先进行DES加密。然后再转成base64
+ (NSString *)base64StringFromText:(NSString *)text withKey:(NSString*)key
{
    if (text && ![text isEqualToString:@""]) {
        //取项目的bundleIdentifier作为KEY
        //NSString *key = [[NSBundle mainBundle] bundleIdentifier];
        NSData *data = [text dataUsingEncoding:NSUTF8StringEncoding];
        //IOS 自带DES加密 Begin
        data = [self DESEncrypt:data WithKey:key];
        //IOS 自带DES加密 End
        return [self base64EncodedStringFrom:data];
    }
    else {
        return @"";
    }
}

//先把base64转为文本。然后再DES解密
+ (NSString *)textFromBase64String:(NSString *)base64 withKey:(NSString*)key
{
    if (base64 && ![base64 isEqualToString:@""]) {
        //取项目的bundleIdentifier作为KEY
        //NSString *key = [[NSBundle mainBundle] bundleIdentifier];
        NSData *data = [self dataWithBase64EncodedString:base64];
        //IOS 自带DES解密 Begin
        data = [self DESDecrypt:data WithKey:key];
        //IOS 自带DES加密 End
        return [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    }
    else {
        return @"";
    }
}

/******************************************************************************
 函数名称 : + (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key
 函数描述 : 文本数据进行DES加密
 输入参数 : (NSData *)data
 (NSString *)key
 输出参数 : N/A
 返回参数 : (NSData *)
 备注信息 : 此函数不可用于过长文本
 ******************************************************************************/
+ (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key
{
    char keyPtr[kCCKeySizeAES256+];
    bzero(keyPtr, sizeof(keyPtr));

    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [data length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    size_t numBytesEncrypted = ;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          keyPtr, kCCBlockSizeDES,
                                          NULL,
                                          [data bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }

    free(buffer);
    return nil;
}

/******************************************************************************
 函数名称 : + (NSData *)DESEncrypt:(NSData *)data WithKey:(NSString *)key
 函数描述 : 文本数据进行DES解密
 输入参数 : (NSData *)data
 (NSString *)key
 输出参数 : N/A
 返回参数 : (NSData *)
 备注信息 : 此函数不可用于过长文本
 ******************************************************************************/
+ (NSData *)DESDecrypt:(NSData *)data WithKey:(NSString *)key
{
    char keyPtr[kCCKeySizeAES256+];
    bzero(keyPtr, sizeof(keyPtr));

    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

    NSUInteger dataLength = [data length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    size_t numBytesDecrypted = ;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          keyPtr, kCCBlockSizeDES,
                                          NULL,
                                          [data bytes], dataLength,
                                          buffer, bufferSize,
                                          &numBytesDecrypted);

    if (cryptStatus == kCCSuccess) {
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }

    free(buffer);
    return nil;
}

/******************************************************************************
 函数名称 : + (NSData *)dataWithBase64EncodedString:(NSString *)string
 函数描述 : base64格式字符串转换为文本数据
 输入参数 : (NSString *)string
 输出参数 : N/A
 返回参数 : (NSData *)
 备注信息 :
 ******************************************************************************/
static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

+ (NSData *)dataWithBase64EncodedString:(NSString *)string
{
    if (string == nil)
        [NSException raise:NSInvalidArgumentException format:nil];
    if ([string length] == )
        return [NSData data];

    static char *decodingTable = NULL;
    if (decodingTable == NULL)
    {
        decodingTable = malloc();
        if (decodingTable == NULL)
            return nil;
        memset(decodingTable, CHAR_MAX, );
        NSUInteger i;
        for (i = ; i < ; i++)
            decodingTable[(short)encodingTable[i]] = i;
    }

    const char *characters = [string cStringUsingEncoding:NSASCIIStringEncoding];
    if (characters == NULL)     //  Not an ASCII string!
        return nil;
    char *bytes = malloc((([string length] + ) / ) * );
    if (bytes == NULL)
        return nil;
    NSUInteger length = ;

    NSUInteger i = ;
    while (YES)
    {
        char buffer[];
        short bufferLength;
        for (bufferLength = ; bufferLength < ; i++)
        {
            if (characters[i] == '\0')
                break;
            if (isspace(characters[i]) || characters[i] == '=')
                continue;
            buffer[bufferLength] = decodingTable[(short)characters[i]];
            if (buffer[bufferLength++] == CHAR_MAX)      //  Illegal character!
            {
                free(bytes);
                return nil;
            }
        }

        if (bufferLength == )
            break;
        if (bufferLength == )      //  At least two characters are needed to produce one byte!
        {
            free(bytes);
            return nil;
        }

        //  Decode the characters in the buffer to bytes.
        bytes[length++] = (buffer[] << ) | (buffer[] >> );
        if (bufferLength > )
            bytes[length++] = (buffer[] << ) | (buffer[] >> );
        if (bufferLength > )
            bytes[length++] = (buffer[] << ) | buffer[];
    }

    bytes = realloc(bytes, length);
    return [NSData dataWithBytesNoCopy:bytes length:length];
}

/******************************************************************************
 函数名称 : + (NSString *)base64EncodedStringFrom:(NSData *)data
 函数描述 : 文本数据转换为base64格式字符串
 输入参数 : (NSData *)data
 输出参数 : N/A
 返回参数 : (NSString *)
 备注信息 :
 ******************************************************************************/
+ (NSString *)base64EncodedStringFrom:(NSData *)data
{
    if ([data length] == )
        return @"";

    char *characters = malloc((([data length] + ) / ) * );
    if (characters == NULL)
        return nil;
    NSUInteger length = ;

    NSUInteger i = ;
    while (i < [data length])
    {
        char buffer[] = {,,};
        short bufferLength = ;
        while (bufferLength <  && i < [data length])
            buffer[bufferLength++] = ((char *)[data bytes])[i++];

        //  Encode the bytes in the buffer to four characters, including padding "=" characters if necessary.
        characters[length++] = encodingTable[(buffer[] & 0xFC) >> ];
        characters[length++] = encodingTable[((buffer[] & 0x03) << ) | ((buffer[] & 0xF0) >> )];
        if (bufferLength > )
            characters[length++] = encodingTable[((buffer[] & 0x0F) << ) | ((buffer[] & 0xC0) >> )];
        else characters[length++] = '=';
        if (bufferLength > )
            characters[length++] = encodingTable[buffer[] & 0x3F];
        else characters[length++] = '=';
    }

    return [[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES];
}

原文地址： http://www.cnblogs.com/thefeelingofsimple/archive/2012/11/29/2794724.html

demo下载地址：https://github.com/qingjoin/iOSDESEncryptDemo