神刀安全网

iOS开发之AES+Base64数据混合加密与解密

"APP的数据安全已经牵动着我们开发者的心,简单的MD5/Base64等已经难以满足当下的数据安全标准,本文简单的介绍下AES与Base64的混合加密与解密"

AES:高级加密标准(英语:Advanced Encryption Standard,缩写:AES),在密码学中又称Rijndael加密法,是美国联邦政府采用的一种区块加密标准。这个标准用来替代原先的DES,已经被多方分析且广为全世界所使用。经过五年的甄选流程,高级加密标准由美国国家标准与技术研究院(NIST)于2001年11月26日发布于FIPS PUB 197,并在2002年5月26日成为有效的标准。2006年,高级加密标准已然成为对称密钥加密中最流行的算法之一。

以上是来自百度百科的解释。

下面我将用代码来阐述其使用方法。 首先我们创建一个NSData的类扩展,命名为AES,创建完如果对的话应该是这样的NSData+AES然后导入如下头文件

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

再增加加解密的方法,方便外部文件的调用,写完.h文件如下

#import <Foundation/Foundation.h> #import <CommonCrypto/CommonDigest.h> #import <CommonCrypto/CommonCryptor.h>  @interface NSData (AES)  //加密 - (NSData *) AES256_Encrypt:(NSString *)key;  //解密 - (NSData *) AES256_Decrypt:(NSString *)key;  //追加64编码 - (NSString *)newStringInBase64FromData;  //同上64编码 + (NSString*)base64encode:(NSString*)str;   @end 

.m文件中依次实现这几个方法,具体如下

#import "NSData+AES.h"  static char base64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";  @implementation NSData (AES)  //加密 - (NSData *) AES256_Encrypt:(NSString *)key{     char keyPtr[kCCKeySizeAES256+1];     bzero(keyPtr, sizeof(keyPtr));     [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];     NSUInteger dataLength = [self length];     size_t bufferSize = dataLength + kCCBlockSizeAES128;     void *buffer = malloc(bufferSize);     size_t numBytesEncrypted = 0;     CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128,     kCCOptionPKCS7Padding | kCCOptionECBMode,     keyPtr, kCCBlockSizeAES128,     NULL,     [self bytes], dataLength,     buffer, bufferSize,     &numBytesEncrypted);     if (cryptStatus == kCCSuccess) {         return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];     }     free(buffer);     return nil; }  //解密 - (NSData *) AES256_Decrypt:(NSString *)key{      char keyPtr[kCCKeySizeAES256+1];     bzero(keyPtr, sizeof(keyPtr));     [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];     NSUInteger dataLength = [self length];     size_t bufferSize = dataLength + kCCBlockSizeAES128;     void *buffer = malloc(bufferSize);     size_t numBytesDecrypted = 0;     CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128,     kCCOptionPKCS7Padding | kCCOptionECBMode,     keyPtr, kCCBlockSizeAES128,     NULL,     [self bytes], dataLength,     buffer, bufferSize,     &numBytesDecrypted);     if (cryptStatus == kCCSuccess) {         return [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted];      }     free(buffer);     return nil; }  //追加64编码 - (NSString *)newStringInBase64FromData              {      NSMutableString *dest = [[NSMutableString alloc] initWithString:@""];      unsigned char * working = (unsigned char *)[self bytes];      int srcLen = (int)[self length];      for (int i=0; i<srcLen; i += 3) {          for (int nib=0; nib<4; nib++) {              int byt = (nib == 0)?0:nib-1;              int ix = (nib+1)*2;              if (i+byt >= srcLen) break;              unsigned char curr = ((working[i+byt] << (8-ix)) & 0x3F);              if (i+nib < srcLen) curr |= ((working[i+nib] >> ix) & 0x3F);              [dest appendFormat:@"%c", base64[curr]];          }      }      return dest;  }    + (NSString*)base64encode:(NSString*)str  {      if ([str length] == 0)      return @"";      const char *source = [str UTF8String];      int strlength  = (int)strlen(source);      char *characters = malloc(((strlength + 2) / 3) * 4);      if (characters == NULL)      return nil;      NSUInteger length = 0;      NSUInteger i = 0;      while (i < strlength) {          char buffer[3] = {0,0,0};          short bufferLength = 0;          while (bufferLength < 3 && i < strlength)          buffer[bufferLength++] = source[i++];          characters[length++] = base64[(buffer[0] & 0xFC) >> 2];          characters[length++] = base64[((buffer[0] & 0x03) << 4) | ((buffer[1] & 0xF0) >> 4)];          if (bufferLength > 1)          characters[length++] = base64[((buffer[1] & 0x0F) << 2) | ((buffer[2] & 0xC0) >> 6)];          else characters[length++] = '=';          if (bufferLength > 2)          characters[length++] = base64[buffer[2] & 0x3F];          else characters[length++] = '=';      }      NSString *g = [[NSString alloc] initWithBytesNoCopy:characters length:length encoding:NSASCIIStringEncoding freeWhenDone:YES];       return g;  }    @end 

AES+Base64的加密方式到此已经结束了,下面讲一下单纯的AES字符串加密的。

和上面的基本上差不多,写一个NSString的类扩展,命名为AES,创建完如果对的话应该是这样的NSString+AES导入如下头文件

#import "NSData+AES.h" 

同样的把加解密的方法写在.h文件中,写完如下

#import <Foundation/Foundation.h> #import "NSData+AES.h"  @interface NSString (AES)  //加密 - (NSString *) AES256_Encrypt:(NSString *)key;  //解密 - (NSString *) AES256_Decrypt:(NSString *)key;  @end 

.m实现方法

//加密 - (NSString *) AES256_Encrypt:(NSString *)key{     const char *cstr = [self cStringUsingEncoding:NSUTF8StringEncoding];     NSData *data = [NSData dataWithBytes:cstr length:self.length];     //对数据进行加密     NSData *result = [data AES256_Encrypt:key];      //转换为2进制字符串     if (result && result.length > 0) {      Byte *datas = (Byte*)[result bytes];     NSMutableString *output = [NSMutableString stringWithCapacity:result.length * 2];     for(int i = 0; i < result.length; i++){         [output appendFormat:@"%02x", datas[i]];     }     return output;     }     return nil; }  //解密 - (NSString *) AES256_Decrypt:(NSString *)key{     //转换为2进制Data     NSMutableData *data = [NSMutableData dataWithCapacity:self.length / 2];     unsigned char whole_byte;     char byte_chars[3] = {'/0','/0','/0'};     int i;     for (i=0; i < [self length] / 2; i++) {     byte_chars[0] = [self characterAtIndex:i*2];     byte_chars[1] = [self characterAtIndex:i*2+1];     whole_byte = strtol(byte_chars, NULL, 16);     [data appendBytes:&whole_byte length:1];     }      //对数据进行解密     NSData* result = [data AES256_Decrypt:key];     if (result && result.length > 0) {         return [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];     }     return nil; } 

到此我们加密的文件基本上都已经OK了,下面我们来简单的的使用一下,具体如下:

#import "ViewController.h" #import "NSString+AES.h"  @interface ViewController ()  @end  @implementation ViewController  - (void)viewDidLoad {     [super viewDidLoad];     // Do any additional setup after loading the view, typically from a nib.      //字符串加密     NSString *key = @"12345678";//Key是和后台约定的key哦,不然无法解密....      NSString *secret = @"aes Bison base64";       NSLog(@"字符串加密---%@",[secret AES256_Encrypt:key]);      //字符串解密     NSLog(@"字符串解密---%@",[[secret AES256_Encrypt:key] AES256_Decrypt:key]);       //NSData加密+base64      NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];      NSData *cipher = [plain AES256_Encrypt:key];      NSLog(@"NSData加密+base64++++%@",[cipher newStringInBase64FromData]);       //解密      plain = [cipher AES256_Decrypt:key];      NSLog(@"NSData解密+base64++++%@", [[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding]);  }   @end 

运行得到打印的结果如下:

2016-03-30 17:31:55.686 AES_256[14242:198853] 字符串加密---07815ca46d20acc3ba4e43d6930c7537496e851a36dbeac34fa30c5796089b02 2016-03-30 17:31:55.687 AES_256[14242:198853] 字符串解密---aes Bison base64 2016-03-30 17:31:55.687 AES_256[14242:198853] NSData加密+base64++++B4FcpG0grMO6TkPWkwx1N0luhRo22+rDT6MMV5YImwI 2016-03-30 17:31:55.687 AES_256[14242:198853] NSData解密+base64++++aes Bison base64 

##值得注意的是Key是和后台约定的key哦,不然无法解密….

最后留下 demo下载地址

好文推荐: 菜鸟程序员2015年年终总结

转载本站任何文章请注明:转载至神刀安全网,谢谢神刀安全网 » iOS开发之AES+Base64数据混合加密与解密

分享到:更多 ()

评论 抢沙发

  • 昵称 (必填)
  • 邮箱 (必填)
  • 网址
分享按钮