ios des加密与解密（对应JAVA加解密）

//
//  NSString+DES.h
//  TestDES
//
//  Created by coooliang on 15/12/25.
//  Copyright © 2015年 coooliang. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface NSString (DES)

+(NSString *)des:(NSString *)str key:(NSString *)key;

+(NSString *)decryptDes:(NSString*)str key:(NSString*)key;

@end

//
//  NSString+DES.m
//  TestDES
//
//  Created by coooliang on 15/12/25.
//  Copyright © 2015年 coooliang. All rights reserved.
//

#import "NSString+DES.h"
#import "GTMBase64.h"
#import <CommonCrypto/CommonCryptor.h>
#import "NSData+DataToHexString.h"

@implementation NSString (DES)

+(NSString *)des:(NSString *)str key:(NSString *)key{
NSString *ciphertext = nil;

NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

char keyPtr[kCCKeySizeAES256+1];
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 = 0;

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

if (cryptStatus == kCCSuccess) {
NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
NSLog(@"data = %@",data);
ciphertext = [data dataToHexString];
NSLog(@"ciphertext = %@",ciphertext);
}
return ciphertext;
}

//解密
+(NSString *)decryptDes:(NSString*)hexString key:(NSString*)key{
NSData *data = [self hexStringToData:hexString];

char keyPtr[kCCKeySizeAES256+1];
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 = 0;

CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES, kCCOptionPKCS7Padding|kCCOptionECBMode, keyPtr, kCCBlockSizeDES, NULL, [data bytes], dataLength, buffer, bufferSize, &numBytesEncrypted);
if(cryptStatus == kCCSuccess){
NSString *string = [[NSString alloc]initWithData:[NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted] encoding:NSUTF8StringEncoding];
NSLog(@"string = %@",string);
return string;
}
free(buffer);
return nil;
}

+(NSData *)hexStringToData:(NSString *)hexString{
const char *chars = [hexString UTF8String];
int i = 0;
int len = (int)hexString.length;
NSMutableData *data = [NSMutableData dataWithCapacity:len/2];
char byteChars[3] = {'\0','\0','\0'};
unsigned long wholeByte;

while (i<len) {
byteChars[0] = chars[i++];
byteChars[1] = chars[i++];
wholeByte = strtoul(byteChars, NULL, 16);
[data appendBytes:&wholeByte length:1];
}
return data;
}

@end

/**
* DES加密，输入内容将被UTF-8编码后进行加密，密钥长度不要大于8位
*
* @param key 密钥
* @param content 明文
* @return 密文
*/
public static String encryptByDES(String key, String content) {
if ((key == null) || (content == null))
return null;

// 生成密钥，密钥长度限定为8位，如果超出8位取前8位
byte[] tmpBytes;
try {
tmpBytes = key.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
log.error("不支持的字符集。", e);
return null;
}
byte[] keyBytes = new byte[8];
for (int i = 0; i < tmpBytes.length && i < keyBytes.length; i++) {
keyBytes[i] = tmpBytes[i];
}
// DES加密成为密文
try {
Key k = new SecretKeySpec(keyBytes, "DES");
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, k);
byte[] output = cipher.doFinal(content.getBytes("UTF-8"));
return ConvertUtil.bytesToHexString(output);
} catch (Exception e) {
log.error("DES加密失败。", e);
}
return null;
}

/**
* DES解密，输入内容是密文，密钥长度不要大于8位
*
* @param key 密钥
* @param cipherText 密文
* @return 明文
*/
public static String decryptByDES(String key, String cipherText) {
if ((key == null) || (cipherText == null))
return null;

// 生成密钥，密钥长度限定为8位，如果超出8位取前8位
byte[] tmpBytes;
try {
tmpBytes = key.getBytes("UTF-8");
} catch (UnsupportedEncodingException e) {
log.error("不支持的字符集。", e);
return null;
}
byte[] keyBytes = new byte[8];
for (int i = 0; i < tmpBytes.length && i < keyBytes.length; i++) {
keyBytes[i] = tmpBytes[i];
}
// DES解密成为明文
try {
Key k = new SecretKeySpec(keyBytes, "DES");
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.DECRYPT_MODE, k);
byte[] output = cipher.doFinal(ConvertUtil.hexStringToBytes(cipherText));
return new String(output, "UTF-8");
} catch (Exception e) {
log.error("DES解密失败。", e);
}
return null;
}

public class ConvertUtil {

public static String bytesToHexString(byte[] src){
StringBuilder stringBuilder = new StringBuilder("");
if (src == null || src.length <= 0) {
return null;
}
for (int i = 0; i < src.length; i++) {
int v = src[i] & 0xFF;
String hv = Integer.toHexString(v);
if (hv.length() < 2) {
stringBuilder.append(0);
}
stringBuilder.append(hv);
}
return stringBuilder.toString();
}

public static byte[] hexStringToBytes(String hexString) {
if (hexString == null || hexString.equals("")) {
return null;
}
hexString = hexString.toUpperCase();
int length = hexString.length() / 2;
char[] hexChars = hexString.toCharArray();
byte[] d = new byte[length];
for (int i = 0; i < length; i++) {
int pos = i * 2;
d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
}
return d;
}

public static String stringToHexString(String str) {
return bytesToHexString(str.getBytes());
}

public static String hexStringtoString(String hexString) {
return new String(hexStringToBytes(hexString));
}

private static byte charToByte(char c) {
return (byte) "0123456789ABCDEF".indexOf(c);
}
}