1 头文件   2   3 #import 
     
         4   5 @interface NSData (AESTest)   6 -(NSData*)AES256EncryptWithKey:(NSString*)key;   7 -(NSData*)AES256DecryptWithKey:(NSString*)key;   8   9 @end  10  11 实现文件  12  13 #import 
      
         14 #import "NSData.h"  15  16  17 @implementation NSData(AESAdditions)  18  19 -(NSData*)AES256EncryptWithKey:(NSString *)key{
     20  21     // 'key' should be 32 bytes for AES256, will be null-padded otherwise  22     char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)  23     bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)  24  25 // fetch key data  26     [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];  27  28     NSUInteger dataLength = [self length];  29  30     //See the doc: For block ciphers, the output size will always be less than or  31 //equal to the input size plus the size of one block.  32 //That's why we need to add the size of one block here  33     size_t bufferSize           = dataLength + kCCBlockSizeAES128;  34     void* buffer                = malloc(bufferSize);  35  36     size_t numBytesEncrypted    = 0;  37     CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,  38                                           keyPtr, kCCKeySizeAES256,  39                                           NULL /* initialization vector (optional) */,  40                                           [self bytes], dataLength, /* input */  41                                           buffer, bufferSize, /* output */  42                                           &numBytesEncrypted);  43  44     if (cryptStatus == kCCSuccess)  45     {
     46         //the returned NSData takes ownership of the buffer and will free it on deallocation  47         return [NSMutableData dataWithBytesNoCopy:buffer length:numBytesEncrypted];  48     }  49  50     free(buffer); //free the buffer;  51     return nil;  52 }  53  54  55  56  57 - (NSData*)AES256DecryptWithKey:(NSString*)key {
     58     // 'key' should be 32 bytes for AES256, will be null-padded otherwise  59     char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)  60     bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)  61  62 // fetch key data  63     [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];  64  65     NSUInteger dataLength = [self length];  66  67     //See the doc: For block ciphers, the output size will always be less than or  68 //equal to the input size plus the size of one block.  69 //That's why we need to add the size of one block here  70     size_t bufferSize           = dataLength + kCCBlockSizeAES128;  71     void* buffer                = malloc(bufferSize);  72  73     size_t numBytesDecrypted    = 0;  74     CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,  75                                           keyPtr, kCCKeySizeAES256,  76                                           NULL /* initialization vector (optional) */,  77                                           [self bytes], dataLength, /* input */  78                                           buffer, bufferSize, /* output */  79                                           &numBytesDecrypted);  80  81     if (cryptStatus == kCCSuccess)  82     {
     83         //the returned NSData takes ownership of the buffer and will free it on deallocation  84         return [NSMutableData dataWithBytesNoCopy:buffer length:numBytesDecrypted];  85     }  86  87     free(buffer); //free the buffer;  88     return nil;  89 }  90 @end  91  92  93  94 调用  95 - (void)loadView {
     96  97  98 NSString *key = @"my password";  99 NSString *secret = @"text to encrypt"; 100 101 NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding]; 102 NSData *cipher = [plain AES256EncryptWithKey:key]; 103 printf("............%s\n", [[cipher description] UTF8String]); 104 105 plain = [cipher AES256DecryptWithKey:key]; 106 printf("............%s\n", [[plain description] UTF8String]); 107 printf("............%s\n", [[[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding] UTF8String]); 108 109 ｝