DES加密

创建一个NSData的类目（category）

#import <Foundation/Foundation.h>
@interface NSData (DES)
- (NSString *)base64Encoding;
+(NSString *) parseByte2HexString:(Byte *) bytes;

@end

类目方法的实现

#import "NSData+DES.h"

@implementation NSData (DES)
static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";

- (NSString *)base64Encoding;
{
if (self.length == 0)
return @"";

char *characters = malloc(self.length*3/2);

if (characters == NULL)
return @"";

int end = self.length - 3;
int index = 0;
int charCount = 0;
int n = 0;

while (index <= end) {
int d = (((int)(((char *)[self bytes])[index]) & 0x0ff) << 16)
| (((int)(((char *)[self bytes])[index + 1]) & 0x0ff) << 8)
| ((int)(((char *)[self bytes])[index + 2]) & 0x0ff);

characters[charCount++] = encodingTable[(d >> 18) & 63];
characters[charCount++] = encodingTable[(d >> 12) & 63];
characters[charCount++] = encodingTable[(d >> 6) & 63];
characters[charCount++] = encodingTable[d & 63];

index += 3;

if(n++ >= 14)
{
n = 0;
characters[charCount++] = ' ';
}
}

if(index == self.length - 2)
{
int d = (((int)(((char *)[self bytes])[index]) & 0x0ff) << 16)
| (((int)(((char *)[self bytes])[index + 1]) & 255) << 8);
characters[charCount++] = encodingTable[(d >> 18) & 63];
characters[charCount++] = encodingTable[(d >> 12) & 63];
characters[charCount++] = encodingTable[(d >> 6) & 63];
characters[charCount++] = '=';
}
else if(index == self.length - 1)
{
int d = ((int)(((char *)[self bytes])[index]) & 0x0ff) << 16;
characters[charCount++] = encodingTable[(d >> 18) & 63];
characters[charCount++] = encodingTable[(d >> 12) & 63];
characters[charCount++] = '=';
characters[charCount++] = '=';
}
NSString * rtnStr = [[NSString alloc] initWithBytesNoCopy:characters length:charCount encoding:NSUTF8StringEncoding freeWhenDone:YES];
return rtnStr;
}

+(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;
}

@end

创建一个管理类

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

@interface MSEncryptUtil : NSObject
+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key;
@end

方法的实现

#import "NSData+DES.h"
#import "MSEncryptUtil.h"

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

@implementation MSEncryptUtil

+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key
{
NSString *ciphertext = nil;
//先编码后再加密
plainText = [plainText stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
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);
if (cryptStatus == kCCSuccess) {
NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
ciphertext = [data base64Encoding];
}
return ciphertext;
}

@end