关于Objective-c和Java下DES加密保持一致的方式

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http://www.cnblogs.com/janken/archive/2012/04/05/2432930.html

首先谢谢4楼id0096替我修改的bug,当时由于只用于密码加密,所以没有测试中文,本次更新添加了objective-c的des解密和中文加密失败的修正。

最近做了一个移动项目,是有服务器和客户端类型的项目,客户端是要登录才行的,登录的密码要用DES加密,服务器是用Java开发的,客户端要同时支持多平台(Android、iOS),在处理iOS的DES加密的时候遇到了一些问题,起初怎么调都调不成和Android端生成的密文相同。最终一个忽然的想法让我找到了问题的所在,现在将代码总结一下,以备自己以后查阅。

首先,Java端的DES加密的实现方式,代码如下:

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 1 public class DES {
2 private static byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };
3
4 public static String encryptDES(String encryptString, String encryptKey)
5 throws Exception {
6 IvParameterSpec zeroIv = new IvParameterSpec(iv);
7 SecretKeySpec key = new SecretKeySpec(encryptKey.getBytes(), "DES");
8 Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
9 cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
10 byte[] encryptedData = cipher.doFinal(encryptString.getBytes());
11 return Base64.encode(encryptedData);
12 }
13 }
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上述代码用到了一个Base64的编码类,其代码的实现方式如下:

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 1 public class Base64 {
2 private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
3 .toCharArray();
4
5 /**
6 * data[]进行编码
7 *
8 * @param data
9 * @return
10 */
11 public static String encode(byte[] data) {
12 int start = 0;
13 int len = data.length;
14 StringBuffer buf = new StringBuffer(data.length * 3 / 2);
15
16 int end = len - 3;
17 int i = start;
18 int n = 0;
19
20 while (i <= end) {
21 int d = ((((int) data[i]) & 0x0ff) << 16)
22 | ((((int) data[i + 1]) & 0x0ff) << 8)
23 | (((int) data[i + 2]) & 0x0ff);
24
25 buf.append(legalChars[(d >> 18) & 63]);
26 buf.append(legalChars[(d >> 12) & 63]);
27 buf.append(legalChars[(d >> 6) & 63]);
28 buf.append(legalChars[d & 63]);
29
30 i += 3;
31
32 if (n++ >= 14) {
33 n = 0;
34 buf.append(" ");
35 }
36 }
37
38 if (i == start + len - 2) {
39 int d = ((((int) data[i]) & 0x0ff) << 16)
40 | ((((int) data[i + 1]) & 255) << 8);
41
42 buf.append(legalChars[(d >> 18) & 63]);
43 buf.append(legalChars[(d >> 12) & 63]);
44 buf.append(legalChars[(d >> 6) & 63]);
45 buf.append("=");
46 } else if (i == start + len - 1) {
47 int d = (((int) data[i]) & 0x0ff) << 16;
48
49 buf.append(legalChars[(d >> 18) & 63]);
50 buf.append(legalChars[(d >> 12) & 63]);
51 buf.append("==");
52 }
53
54 return buf.toString();
55 }
56
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以上便是Java端的DES加密方法的全部实现过程。

我还编写了一个将byte的二进制转换成16进制的方法,以便调试的时候使用打印输出加密后的byte数组的内容,这个方法不是加密的部分,只是为调试而使用的:

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 1     /**将二进制转换成16进制 
2 * @param buf
3 * @return String
4 */
5 public static String parseByte2HexStr(byte buf[]) {
6 StringBuffer sb = new StringBuffer();
7 for (int i = 0; i < buf.length; i++) {
8 String hex = Integer.toHexString(buf[i] & 0xFF);
9 if (hex.length() == 1) {
10 hex = '0' + hex;
11 }
12 sb.append(hex.toUpperCase());
13 }
14 return sb.toString();
15 }
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下面是Objective-c在iOS上实现的DES加密算法:

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 1 const Byte iv[] = {1,2,3,4,5,6,7,8}; 2 +(NSString *) encryptUseDES:(NSString *)plainText key:(NSString *)key 3 { 4     NSString *ciphertext = nil; 5     NSData *textData = [plainText dataUsingEncoding:NSUTF8StringEncoding]; 6     NSUInteger dataLength = [textData length]; 7     unsigned char buffer[1024]; 8     memset(buffer, 0, sizeof(char)); 9     size_t numBytesEncrypted = 0;10     CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmDES,11                                           kCCOptionPKCS7Padding,12                                           [key UTF8String], kCCKeySizeDES,13                                           iv,14                                           [textData bytes], dataLength,15                                           buffer, 1024,16                                           &numBytesEncrypted);17     if (cryptStatus == kCCSuccess) {18         NSData *data = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesEncrypted];19         ciphertext = [Base64 encode:data];20     }21     return ciphertext;22 }
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下面也是Objective-c的一个二进制转换为16进制的方法,也是为了测试方便查看写的:

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 1 +(NSString *) parseByte2HexString:(Byte *) bytes
2 {
3 NSMutableString *hexStr = [[NSMutableString alloc]init];
4 int i = 0;
5 if(bytes)
6 {
7 while (bytes[i] != '\0')
8 {
9 NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];///16进制数
10 if([hexByte length]==1)
11 [hexStr appendFormat:@"0%@", hexByte];
12 else
13 [hexStr appendFormat:@"%@", hexByte];
14
15 i++;
16 }
17 }
18 NSLog(@"bytes 的16进制数为:%@",hexStr);
19 return hexStr;
20 }
21
22 +(NSString *) parseByteArray2HexString:(Byte[]) bytes
23 {
24 NSMutableString *hexStr = [[NSMutableString alloc]init];
25 int i = 0;
26 if(bytes)
27 {
28 while (bytes[i] != '\0')
29 {
30 NSString *hexByte = [NSString stringWithFormat:@"%x",bytes[i] & 0xff];///16进制数
31 if([hexByte length]==1)
32 [hexStr appendFormat:@"0%@", hexByte];
33 else
34 [hexStr appendFormat:@"%@", hexByte];
35
36 i++;
37 }
38 }
39 NSLog(@"bytes 的16进制数为:%@",hexStr);
40 return hexStr;
41 }
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以上的加密方法所在的包是CommonCrypto/CommonCryptor.h。

以上便实现了Objective-c和Java下在相同的明文和密钥的情况下生成相同明文的算法。

Base64的算法可以用你们自己写的那个,不一定必须使用我提供的这个。解密的时候还要用Base64进行密文的转换。

iOS下的Base64算法在后面 。

JAVA下的解密算法如下:

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 1   private static byte[] iv = { 1, 2, 3, 4, 5, 6, 7, 8 };    
2   public static String decryptDES(String decryptString, String decryptKey)
3 throws Exception {
4 byte[] byteMi = Base64.decode(decryptString);
5 IvParameterSpec zeroIv = new IvParameterSpec(iv);
6 SecretKeySpec key = new SecretKeySpec(decryptKey.getBytes(), "DES");
7 Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
8 cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);
9 byte decryptedData[] = cipher.doFinal(byteMi);
10
11 return new String(decryptedData);
12 }
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Base64的decode方法如下:

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 1   public static byte[] decode(String s) {
2
3 ByteArrayOutputStream bos = new ByteArrayOutputStream();
4 try {
5 decode(s, bos);
6 } catch (IOException e) {
7 throw new RuntimeException();
8 }
9 byte[] decodedBytes = bos.toByteArray();
10 try {
11 bos.close();
12 bos = null;
13 } catch (IOException ex) {
14 System.err.println("Error while decoding BASE64: " + ex.toString());
15 }
16 return decodedBytes;
17 }
18 private static void decode(String s, OutputStream os) throws IOException {
19 int i = 0;
20
21 int len = s.length();
22
23 while (true) {
24 while (i < len && s.charAt(i) <= ' ')
25 i++;
26
27 if (i == len)
28 break;
29
30 int tri = (decode(s.charAt(i)) << 18)
31 + (decode(s.charAt(i + 1)) << 12)
32 + (decode(s.charAt(i + 2)) << 6)
33 + (decode(s.charAt(i + 3)));
34
35 os.write((tri >> 16) & 255);
36 if (s.charAt(i + 2) == '=')
37 break;
38 os.write((tri >> 8) & 255);
39 if (s.charAt(i + 3) == '=')
40 break;
41 os.write(tri & 255);
42
43 i += 4;
44 }
45 }
46 private static int decode(char c) {
47 if (c >= 'A' && c <= 'Z')
48 return ((int) c) - 65;
49 else if (c >= 'a' && c <= 'z')
50 return ((int) c) - 97 + 26;
51 else if (c >= '0' && c <= '9')
52 return ((int) c) - 48 + 26 + 26;
53 else
54 switch (c) {
55 case '+':
56 return 62;
57 case '/':
58 return 63;
59 case '=':
60 return 0;
61 default:
62 throw new RuntimeException("unexpected code: " + c);
63 }
64 }
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Objective-c在下的DES解密算法:

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 1 +(NSString *)decryptUseDES:(NSString *)cipherText key:(NSString *)key 2 { 3     NSString *plaintext = nil; 4     NSData *cipherdata = [Base64 decode:cipherText]; 5     unsigned char buffer[1024]; 6     memset(buffer, 0, sizeof(char)); 7     size_t numBytesDecrypted = 0; 8     CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmDES, 9                                           kCCOptionPKCS7Padding,10                                           [key UTF8String], kCCKeySizeDES,11                                           iv,12                                           [cipherdata bytes], [cipherdata length],13                                           buffer, 1024,14                                           &numBytesDecrypted);15     if(cryptStatus == kCCSuccess) {16         NSData *plaindata = [NSData dataWithBytes:buffer length:(NSUInteger)numBytesDecrypted];17         plaintext = [[NSString alloc]initWithData:plaindata encoding:NSUTF8StringEncoding];18     }19     return plaintext;20 }
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下面是objective-c 实现的Base64工具对象,当然你也可以选择使用google的那个Base64类——GTMBase64(功能很强大),初步测试使用GTMBase64和使用我写的这个Base64效果都是一样的。

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  1 static const char encodingTable[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";  2   3 @interface Base64()  4 +(int)char2Int:(char)c;  5 @end  6   7 @implementation Base64  8   9 +(NSString *)encode:(NSData *)data 10 { 11     if (data.length == 0) 12         return nil; 13      14     char *characters = malloc(data.length * 3 / 2); 15      16     if (characters == NULL) 17         return nil; 18      19     int end = data.length - 3; 20     int index = 0; 21     int charCount = 0; 22     int n = 0; 23      24     while (index <= end) { 25         int d = (((int)(((char *)[data bytes])[index]) & 0x0ff) << 16) 26         | (((int)(((char *)[data bytes])[index + 1]) & 0x0ff) << 8) 27         | ((int)(((char *)[data bytes])[index + 2]) & 0x0ff); 28          29         characters[charCount++] = encodingTable[(d >> 18) & 63]; 30         characters[charCount++] = encodingTable[(d >> 12) & 63]; 31         characters[charCount++] = encodingTable[(d >> 6) & 63]; 32         characters[charCount++] = encodingTable[d & 63]; 33          34         index += 3; 35          36         if(n++ >= 14) 37         { 38             n = 0; 39             characters[charCount++] = ' '; 40         } 41     } 42      43     if(index == data.length - 2) 44     { 45         int d = (((int)(((char *)[data bytes])[index]) & 0x0ff) << 16) 46         | (((int)(((char *)[data bytes])[index + 1]) & 255) << 8); 47         characters[charCount++] = encodingTable[(d >> 18) & 63]; 48         characters[charCount++] = encodingTable[(d >> 12) & 63]; 49         characters[charCount++] = encodingTable[(d >> 6) & 63]; 50         characters[charCount++] = '='; 51     } 52     else if(index == data.length - 1) 53     { 54         int d = ((int)(((char *)[data bytes])[index]) & 0x0ff) << 16; 55         characters[charCount++] = encodingTable[(d >> 18) & 63]; 56         characters[charCount++] = encodingTable[(d >> 12) & 63]; 57         characters[charCount++] = '='; 58         characters[charCount++] = '='; 59     } 60     NSString * rtnStr = [[NSString alloc] initWithBytesNoCopy:characters length:charCount encoding:NSUTF8StringEncoding freeWhenDone:YES]; 61     return rtnStr; 62  63 } 64  65 +(NSData *)decode:(NSString *)data 66 { 67     if(data == nil || data.length <= 0) { 68         return nil; 69     } 70     NSMutableData *rtnData = [[NSMutableData alloc]init]; 71     int slen = data.length; 72     int index = 0; 73     while (true) { 74         while (index < slen && [data characterAtIndex:index] <= ' ') { 75             index++; 76         } 77         if (index >= slen || index  + 3 >= slen) { 78             break; 79         } 80  81         int byte = ([self char2Int:[data characterAtIndex:index]] << 18) + ([self char2Int:[data characterAtIndex:index + 1]] << 12) + ([self char2Int:[data characterAtIndex:index + 2]] << 6) + [self char2Int:[data characterAtIndex:index + 3]]; 82         Byte temp1 = (byte >> 16) & 255; 83         [rtnData appendBytes:&temp1 length:1]; 84         if([data characterAtIndex:index + 2] == '=') { 85             break; 86         } 87         Byte temp2 = (byte >> 8) & 255; 88         [rtnData appendBytes:&temp2 length:1]; 89         if([data characterAtIndex:index + 3] == '=') { 90             break; 91         } 92         Byte temp3 = byte & 255; 93         [rtnData appendBytes:&temp3 length:1]; 94         index += 4; 95  96     } 97     return rtnData; 98 } 99 100 +(int)char2Int:(char)c101 {102     if (c >= 'A' && c <= 'Z') {103         return c - 65;104     } else if (c >= 'a' && c <= 'z') {105         return c - 97 + 26;106     } else if (c >= '0' && c <= '9') {107         return c - 48 + 26 + 26;108     } else {109         switch(c) {110             case '+':111                 return 62;112             case '/':113                 return 63;114             case '=':115                 return 0;116             default:117                 return -1;118         }119     }120 }121 122 @end
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这个和java端的Base64的是一个算法,只是根据语言的特点不同有少许的改动。

 

Java端的测试代码如下:

1     String plaintext = "abcd";
2 String ciphertext = DES.encryptDES(plaintext, "20120401");
3 System.out.println("明文:" + plaintext);
4 System.out.println("密钥:" + "20120401");
5 System.out.println("密文:" + ciphertext);
6 System.out.println("解密后:" + DES.decryptDES(ciphertext, "20120401"));

输出结果:

明文:abcd
密钥:20120401
密文:W7HR43/usys=
解密后:abcd


Objective-c端的测试代码如下:

1     NSString *plaintext = @"abcd";
2 NSString *ciphertext = [EncryptUtil encryptUseDES:plaintext key:@"20120401"];
3 NSLog(@"明文:%@",plaintext);
4 NSLog(@"秘钥:%@",@"20120401");
5 NSLog(@"密文:%@",ciphertext);

输出结果:

1 2012-04-05 12:00:47.348 TestEncrypt[806:f803] 明文:abcd
2 2012-04-05 12:00:47.350 TestEncrypt[806:f803] 秘钥:20120401
3 2012-04-05 12:00:47.350 TestEncrypt[806:f803] 密文:W7HR43/usys=


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