欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

使用 DES 算法对数据加密

程序员文章站 2022-05-15 19:30:01
...

使用 DES 算法对数据加密

DES算法

提供高质量的数据保护,防止数据未经授权的泄露和未被察觉的修改

具有相当高的复杂性,使得破译的开销超过可能获得的利益,同时又要便于理解和掌握

DES密码*的安全性应该不依赖于算法的保密,其安全性仅以加***的保密为基础

实现经济,运行有效,并且适用于多种完全不同的应用

 

苹果本身支持DES加密,在项目中引入头文件 CommonCrypto/CommonCryptor.h 即可使用相关函数.

我自己对其进行了封装,支持ARC与非ARC

YXCrypto.h

//
//  YXCrypto.h
//  用秘钥给字符串加密或者解密
//
//  Created by YouXian on 14-3-18.
//  Copyright (c) 2014年 YouXian. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface YXCrypto : NSObject

/*!
 * 给字符串加密
 */
+ (NSString *)DesEncryptString:(NSString*)src WithKey:(NSString *)key;

/*!
 * 给字符串解密
 */
+ (NSString *)DesDecryptString:(NSString*)src WithKey:(NSString *)key;

@end

YXCrypto.m
//
//  YXCrypto.m
//  用秘钥给字符串加密或者解密
//
//  Created by YouXian on 14-3-18.
//  Copyright (c) 2014年 YouXian. All rights reserved.
//

#import "YXCrypto.h"
#import <CommonCrypto/CommonCryptor.h>

#if __has_feature(objc_arc)
// ARC
#define Auto_Release(obj)
#define Safe_Release(obj)
#else
// 非ARC
#define Auto_Release(obj) [obj autorelease]
#define Safe_Release(obj) [obj release]; obj = nil
#endif

static YXCrypto *shareInstance = nil;

@implementation YXCrypto

/*!
 * 给字符串加密
 */
+ (NSString *)DesEncryptString:(NSString*)src WithKey:(NSString *)key {
    NSString* strRet = @"";
    
    if (shareInstance == nil)
    {
        shareInstance = [[YXCrypto alloc] init];
    }
    
    // encrypt source content
    NSData* bytes = [src dataUsingEncoding:NSUTF8StringEncoding];
    NSData* data = [shareInstance DesCryptWithOperation:kCCEncrypt
                                                  bytes:bytes
                                                    key:key];
    
    // format bytes to visible string
    char* pBuff = (char*)[data bytes];
    for (int i=0; i<data.length; i++) {
        strRet = [strRet stringByAppendingFormat:@"%02X", pBuff[i]& 0xFF];
    }
    return strRet;
}

/*!
 * 给字符串解密
 */
+ (NSString *)DesDecryptString:(NSString*)src WithKey:(NSString *)key
{
    if (shareInstance == nil)
    {
        shareInstance = [[YXCrypto alloc] init];
    }
    
    static unsigned char _map_ch2hex[] =
    {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
        0, 0, 0, 0, 0, 0, 0,    // :, ;, <, =, >, ?, @,
        0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
    };
    
    // decode source content to bytes
    unsigned char* bytes = (unsigned char*)malloc((src.length+1)*sizeof(unsigned char));
    [[src uppercaseString] getCString:(char*)bytes maxLength:src.length+1 encoding:NSUTF8StringEncoding];
    unsigned char *p1 = bytes, *p2 = bytes;
    int n = src.length/2;
    for (int i=0; i<n; i++) {
        *p1 = _map_ch2hex[*p2-'0'] * 0x10 + _map_ch2hex[*(p2+1)-'0'];
        p1++;
        p2+=2;
    }
    NSData* data = [NSData dataWithBytes:bytes
                                  length:n];
    
    // decrypt source bytes
    NSData* dataOut = [shareInstance DesCryptWithOperation:kCCDecrypt
                                                     bytes:data
                                                       key:key];
    free(bytes);
    
    NSString* strRet = [[NSString alloc] initWithData:dataOut
                                             encoding:NSUTF8StringEncoding];
    Auto_Release(strRet);
    
    return strRet;
}

- (NSData *)DesCryptWithOperation:(CCOperation)operation bytes:(NSData*)bytes key:(NSString *)key {
    
    NSUInteger dataLength = [bytes length];
    
    size_t bufferSize = ([bytes length] + kCCBlockSizeDES) & ~(kCCBlockSizeDES - 1);
    unsigned char *buffer = (unsigned char *)malloc(bufferSize*sizeof(unsigned char));
    memset((void*)buffer, 0, bufferSize);
    
    size_t numBytesCrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(operation,
                                          kCCAlgorithmDES,
                                          kCCOptionPKCS7Padding | kCCOptionECBMode,
                                          (void const*)[key UTF8String],
                                          kCCKeySizeDES,
                                          NULL,
                                          [bytes bytes], dataLength,
                                          (void*)buffer, bufferSize,
                                          &numBytesCrypted);
    NSData* dataRet = nil;
    if (cryptStatus == kCCSuccess) {
        dataRet = [[NSData alloc] initWithBytes:buffer length:numBytesCrypted];
        Auto_Release(dataRet);
    }
    free(buffer);
    return dataRet;
}

@end

使用:

使用 DES 算法对数据加密

 

 

附录1:https://github.com/alfaromeodev/Cryptor



//
//  Cryptor.h
//  test
//
//  Created by Da Zhang on 11/5/12.
//  Copyright 2012 __MyCompanyName__. All rights reserved.
//

#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonDigest.h>
#import <CommonCrypto/CommonCryptor.h>


@interface Cryptor : NSObject {
    
}

/*
 all the methods below only support utf8 string
 */
+ (NSString *)encodeMD5:(NSString *)str;

+ (NSString *)encodeDES:(NSString *)plainString key:(NSString *)key;
+ (NSString *)decodeDES:(NSString *)decodedString key:(NSString*)key;

+ (NSString *)encodeBase64:(NSString *)plainString;
+ (NSString *)decodeBase64:(NSString *)decodedString;

@end


//
//  Cryptor.m
//  test
//
//  Created by Da Zhang on 11/5/12.
//  Copyright 2012 __MyCompanyName__. All rights reserved.
//

#import "Cryptor.h"

@interface Cryptor ()

+ (NSString *)encodeBase64WithData:(NSData *)objData;
+ (NSData *)decodeBase64WithUTF8String:(NSString *)strBase64;
+ (NSString *)parseByte2HexString:(Byte *)bytes;

@end


static const char _base64EncodingTable[64] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
static const short _base64DecodingTable[256] = {
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1, -2, -1, -1, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, 62, -2, -2, -2, 63,
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -2, -2, -2, -2, -2, -2,
    -2,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14,
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -2, -2, -2, -2, -2,
    -2, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2,
    -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2
};


@implementation Cryptor


#pragma mark private section
+ (NSData *)decodeBase64WithUTF8String:(NSString *)strBase64 {
    const char * objPointer = [strBase64 cStringUsingEncoding:NSUTF8StringEncoding];
    int intLength = strlen(objPointer);
    int intCurrent;
    int i = 0, j = 0, k;

    unsigned char * objResult;
    objResult = calloc(intLength, sizeof(char));

    // Run through the whole string, converting as we go
    while ( ((intCurrent = *objPointer++) != '\0') && (intLength-- > 0) ) {
        if (intCurrent == '=') {
            if (*objPointer != '=' && ((i % 4) == 1)) {// || (intLength > 0)) {
                // the padding character is invalid at this point -- so this entire string is invalid
                free(objResult);
                return nil;
            }
            continue;
        }

        intCurrent = _base64DecodingTable[intCurrent];
        if (intCurrent == -1) {
            // we're at a whitespace -- simply skip over
            continue;
        } else if (intCurrent == -2) {
            // we're at an invalid character
            free(objResult);
            return nil;
        }

        switch (i % 4) {
            case 0:
                objResult[j] = intCurrent << 2;
                break;

            case 1:
                objResult[j++] |= intCurrent >> 4;
                objResult[j] = (intCurrent & 0x0f) << 4;
                break;

            case 2:
                objResult[j++] |= intCurrent >>2;
                objResult[j] = (intCurrent & 0x03) << 6;
                break;

            case 3:
                objResult[j++] |= intCurrent;
                break;
        }
        i++;
    }

    // mop things up if we ended on a boundary
    k = j;
    if (intCurrent == '=') {
        switch (i % 4) {
            case 1:
                // Invalid state
                free(objResult);
                return nil;

            case 2:
                k++;
                // flow through
            case 3:
                objResult[k] = 0;
        }
    }

    // Cleanup and setup the return NSData
    NSData * objData = [[[NSData alloc] initWithBytes:objResult length:j] autorelease];
    free(objResult);
    return objData;
}

+ (NSString *)encodeBase64WithData:(NSData *)objData {
    const unsigned char * objRawData = [objData bytes];
    char * objPointer;
    char * strResult;

    // Get the Raw Data length and ensure we actually have data
    int intLength = [objData length];
    if (intLength == 0) return nil;

    // Setup the String-based Result placeholder and pointer within that placeholder
    strResult = (char *)calloc(((intLength + 2) / 3) * 4, sizeof(char));
    objPointer = strResult;

    // Iterate through everything
    while (intLength > 2) { // keep going until we have less than 24 bits
        *objPointer++ = _base64EncodingTable[objRawData[0] >> 2];
        *objPointer++ = _base64EncodingTable[((objRawData[0] & 0x03) << 4) + (objRawData[1] >> 4)];
        *objPointer++ = _base64EncodingTable[((objRawData[1] & 0x0f) << 2) + (objRawData[2] >> 6)];
        *objPointer++ = _base64EncodingTable[objRawData[2] & 0x3f];

        // we just handled 3 octets (24 bits) of data
        objRawData += 3;
        intLength -= 3;
    }

    // now deal with the tail end of things
    if (intLength != 0) {
        *objPointer++ = _base64EncodingTable[objRawData[0] >> 2];
        if (intLength > 1) {
            *objPointer++ = _base64EncodingTable[((objRawData[0] & 0x03) << 4) + (objRawData[1] >> 4)];
            *objPointer++ = _base64EncodingTable[(objRawData[1] & 0x0f) << 2];
            *objPointer++ = '=';
        } else {
            *objPointer++ = _base64EncodingTable[(objRawData[0] & 0x03) << 4];
            *objPointer++ = '=';
            *objPointer++ = '=';
        }
    }

    // Terminate the string-based result
    *objPointer = '\0';

    // Return the results as an NSString object
    return [NSString stringWithCString:strResult encoding:NSUTF8StringEncoding];
}

+ (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;
}


#pragma mark public section
+ (NSString *)encodeMD5:(NSString *)str {

    const char *cStr = [str UTF8String];

    unsigned char result[CC_MD5_DIGEST_LENGTH];

    CC_MD5( cStr, strlen(cStr), result );

    return [NSString 

            stringWithFormat: @"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",

            result[0], result[1],

            result[2], result[3],

            result[4], result[5],

            result[6], result[7],

            result[8], result[9],

            result[10], result[11],

            result[12], result[13],

            result[14], result[15]

            ];

}

+ (NSString *)encodeBase64:(NSString *)plainString {
    return [Cryptor encodeBase64WithData:[plainString dataUsingEncoding:NSUTF8StringEncoding]];
}

+ (NSString *)decodeBase64:(NSString *)decodedString {
    NSData * objData = [Cryptor decodeBase64WithUTF8String:decodedString];
    return [[NSString alloc] initWithData:objData encoding:NSUTF8StringEncoding];
}

+ (NSString *)encodeDES:(NSString *)plainString key:(NSString *)key {
    NSString *ciphertext = nil;
    const char *textBytes = [plainString UTF8String];
    NSUInteger dataLength = strlen(textBytes);
    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 = [[Cryptor encodeBase64WithData:data] autorelease];
    }
    return ciphertext;
}

+ (NSString *)decodeDES:(NSString*)decodedString key:(NSString*)key {
    NSData* cipherData = [Cryptor decodeBase64WithUTF8String:decodedString];
    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;
}

@end

附录2:AES加密

NSData+AES.h + NSData+AES.m


#import <Foundation/Foundation.h>

/**
 * Adds AES encryption and decryption capabilities to NSData.
 */
@interface NSData (AES)

/**
 * Encrypt NSData using AES256 with a given symmetric encryption key.
 * @param key The symmetric encryption key
 */
- (NSData *)AES256EncryptWithKey:(NSString *)key;

/**
 * Decrypt NSData using AES256 with a given symmetric encryption key.
 * @param key The symmetric encryption key
 */
- (NSData *)AES256DecryptWithKey:(NSString *)key;

@end


#import "NSData+AES.h"
#import <CommonCrypto/CommonCryptor.h>

@implementation NSData (AES)

- (NSData *)AES256EncryptWithKey:(NSString *)key
{
    // 'key' should be 32 bytes for AES256, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
    
    // fetch key data
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSUInteger dataLength = [self length];
    
    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    
    size_t numBytesEncrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                          keyPtr, kCCKeySizeAES256,
                                          NULL /* initialization vector (optional) */,
                                          [self bytes], dataLength, /* input */
                                          buffer, bufferSize, /* output */
                                          &numBytesEncrypted);
    if (cryptStatus == kCCSuccess) {
        //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
    }
    
    free(buffer); //free the buffer;
    return nil;
}

- (NSData *)AES256DecryptWithKey:(NSString *)key {
    // 'key' should be 32 bytes for AES256, will be null-padded otherwise
    char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)
    
    // fetch key data
    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];
    
    NSUInteger dataLength = [self length];
    
    //See the doc: For block ciphers, the output size will always be less than or
    //equal to the input size plus the size of one block.
    //That's why we need to add the size of one block here
    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);
    
    size_t numBytesDecrypted = 0;
    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                          keyPtr, kCCKeySizeAES256,
                                          NULL /* initialization vector (optional) */,
                                          [self bytes], dataLength, /* input */
                                          buffer, bufferSize, /* output */
                                          &numBytesDecrypted);
    
    if (cryptStatus == kCCSuccess) {
        //the returned NSData takes ownership of the buffer and will free it on deallocation
        return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];
    }
    
    free(buffer); //free the buffer;
    return nil;
}

@end