ios--加密、解密
2015-01-26 16:55 doudo 阅读(267) 评论(0) 编辑 收藏 举报一、des加、解密:
1.原理:DES加密 :用CCCrypt函数加密一下,然后用base64编码下,传过去
DES解密 :把收到的数据根据base64,decode一下,然后再用CCCrypt函数解密,得到原本的数据
2.需要包含:
#import <CommonCrypto/CommonCryptor.h> (CCCrypt所在的文件)
#import "GTMBase64.h"(base64算法)
3.具体实现:
const Byte iv[] = {1,2,3,4,5,6,7,8};
//加密
+(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key
{
NSString *ciphertext = nil;
NSData *textData = [plainText dataUsingEncoding:NSUTF8StringEncoding];
NSUInteger dataLength = [textData length];
unsigned char buffer[1024];
memset(buffer, 0, sizeof(char));
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,
kCCOptionPKCS7Padding,
[key UTF8String], kCCKeySizeDES,
iv,
[textData bytes], dataLength,
buffer, 1024,
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];
ciphertext = [[NSString alloc] initWithData:[GTMBase64 encodeData:data] encoding:NSUTF8StringEncoding];
}
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];
}
return plainText;
}
附:Java端的DES加解密的实现方式,代码如下:
public class DES {
private static byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };
public static String encryptDES(String encryptString, String encryptKey)
throws Exception {
IvParameterSpec zeroIv = new IvParameterSpec(iv);
SecretKeySpec key = new SecretKeySpec(encryptKey.getBytes(), "DES");
Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
byte[] encryptedData = cipher.doFinal(encryptString.getBytes());
return Base64.encode(encryptedData);
}
}
上述代码用到了一个Base64的编码类,其代码的实现方式如下:
public class Base64 {
private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
.toCharArray();
/**
* data[]进行编码
*
* @param data
* @return
*/
public static String encode(byte[] data) {
int start = 0;
int len = data.length;
StringBuffer buf = new StringBuffer(data.length * 3 / 2);
int end = len - 3;
int i = start;
int n = 0;
while (i <= end) {
int d = ((((int) data[i]) & 0x0ff) << 16)
| ((((int) data[i + 1]) & 0x0ff) << 8)
| (((int) data[i + 2]) & 0x0ff);
buf.append(legalChars[(d >> 18) & 63]);
buf.append(legalChars[(d >> 12) & 63]);
buf.append(legalChars[(d >> 6) & 63]);
buf.append(legalChars[d & 63]);
i += 3;
if (n++ >= 14) {
n = 0;
buf.append(" ");
}
}
if (i == start + len - 2) {
int d = ((((int) data[i]) & 0x0ff) << 16)
| ((((int) data[i + 1]) & 255) << 8);
buf.append(legalChars[(d >> 18) & 63]);
buf.append(legalChars[(d >> 12) & 63]);
buf.append(legalChars[(d >> 6) & 63]);
buf.append("=");
} else if (i == start + len - 1) {
int d = (((int) data[i]) & 0x0ff) << 16;
buf.append(legalChars[(d >> 18) & 63]);
buf.append(legalChars[(d >> 12) & 63]);
buf.append("==");
}
return buf.toString();
}
}
二、MD5加密
不可逆
128位或者64位串,byte数字长度就是16和8,一般表示是使用16进制来表示的话,1个byte转换成2个16bit,分别表示高地位,所以生成的字符串是16位或者是32位的,16位其实是从32位中的中间部分抽出来的。
我们所说的密码多少位,是表示多少bit,转换成byte数组的话,就是除以8,但是如果输出16进制的话就是除以4,因为"1111 1111"="FF";
举例来说:256位 byte数组或者NSData的length就是256/8=32 输出16进制就是32*2=64位
JAVA代码:
//byte字节转换成16进制的字符串MD5Utils.hexString
public static String hexString(byte[] bytes){
StringBuffer hexValue = new StringBuffer();
for (int i = 0; i < bytes.length; i++) {
int val = ((int) bytes[i]) & 0xff;
if (val < 16)
hexValue.append("0");
hexValue.append(Integer.toHexString(val));
}
return hexValue.toString();
}
public byte[] eccrypt(String info) throws NoSuchAlgorithmException{
MessageDigest md5 = MessageDigest.getInstance("MD5");
byte[] srcBytes = info.getBytes();
//使用srcBytes更新摘要
md5.update(srcBytes);
//完成哈希计算,得到result
byte[] resultBytes = md5.digest();
return resultBytes;
}
public static void main(String args[]) throws NoSuchAlgorithmException{
String msg = "欢迎光临JerryVon的博客";
EncrypMD5 md5 = new EncrypMD5();
byte[] resultBytes = md5.eccrypt(msg);
System.out.println("密文是:" + MD5Utils.hexString(resultBytes));
System.out.println("明文是:" + msg);
}
Objective-C代码:(此处一般用32位)
最后结果是:
明文:欢迎光临JerryVon的博客
密文(32位):3635dc132ba0e49f17534e749b8a99d1
密文(16位):2ba0e49f17534e74
只要比较最后的HEX值,就可以查看原来的串是否相等。
还可以对MD5进行二次加密,也就是对原串进行2次MD5加密