学步园

@interface NSData (AESTest)

- (NSData*)AES256EncryptWithKey:(NSString*)key;

- (NSData*)AES256DecryptWithKey:(NSString*)key;

@end

NSData+AESTest
.m 代码：

#import <CommonCrypto/CommonCryptor.h

#import 
"NSData+ AESTest
.h"
 

@implementation NSData (AESAdditions)


- (NSData*)AES256EncryptWithKey:(NSString*)key {


    // 'key' should be 32 bytes for AES256, will be null-padded otherwise


    char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)


    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)


 


    // fetch key data


    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];


 


    NSUInteger dataLength = [self length];


 


    //See the doc: For block ciphers, the output size will always be less than or


    //equal to the input size plus the size of one block.


    //That's why we need to add the size of one block here


    size_t bufferSize           = dataLength + kCCBlockSizeAES128;


    void* buffer                = malloc(bufferSize);


 


    size_t numBytesEncrypted    = 0;


    CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,


                                          keyPtr, kCCKeySizeAES256,


                                          NULL /* initialization vector (optional) */,


                                          [self bytes], dataLength, /* input */


                                          buffer, bufferSize, /* output */


                                          &numBytesEncrypted);


 


    if (cryptStatus == kCCSuccess)


    {


        //the returned NSData takes ownership of the buffer and will free it on deallocation


        return [NSMutableData dataWithBytesNoCopy:buffer length:numBytesEncrypted];


    }


 


    free(buffer); //free the buffer;


    return nil;


}



- (NSData*)AES256DecryptWithKey:(NSString*)key {


    // 'key' should be 32 bytes for AES256, will be null-padded otherwise


    char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused)


    bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)


 


    // fetch key data


    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];


 


    NSUInteger dataLength = [self length];


 


    //See the doc: For block ciphers, the output size will always be less than or


    //equal to the input size plus the size of one block.


    //That's why we need to add the size of one block here


    size_t bufferSize           = dataLength + kCCBlockSizeAES128;


    void* buffer                = malloc(bufferSize);


 


    size_t numBytesDecrypted    = 0;


    CCCryptorStatus cryptStatus = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,


                                          keyPtr, kCCKeySizeAES256,


                                          NULL /* initialization vector (optional) */,


                                          [self bytes], dataLength, /* input */


                                          buffer, bufferSize, /* output */


                                          &numBytesDecrypted);


 


    if (cryptStatus == kCCSuccess)


    {


        //the returned NSData takes ownership of the buffer and will free it on deallocation


        return [NSMutableData dataWithBytesNoCopy:buffer length:numBytesDecrypted];


    }


 


    free(buffer); //free the buffer;


    return nil;


}


@end

测试代码

#import 
"NSData+ AESTest
.h"

int
 main 
(
int
 argc
,
 
const
 
char
 
*
 argv
[])
 
{


        
NSAutoreleasePool
 
*
 pool 
=
 
[[
NSAutoreleasePool
 alloc
]
 init
];



        
NSString
 
*
key 
=
 
@
"my password"
;


        
NSString
 
*
secret 
=
 
@
"text to encrypt"
;



        
NSData
 
*
plain 
=
 
[
secret dataUsingEncoding
:
NSUTF8StringEncoding
];


        
NSData
 
*
cipher 
=
 
[
plain AES256EncryptWithKey
:
key
];


        printf
(
"%s/n"
,
 
[[
cipher description
]
 UTF8String
]);



        plain 
=
 
[
cipher AES256DecryptWithKey
:
key
];


        printf
(
"%s/n"
,
 
[[
plain description
]
 UTF8String
]);


        printf
(
"%s/n"
,
 
[[[
NSString
 alloc
]
 initWithData
:
plain encoding
:
NSUTF8StringEncoding
]
 UTF8String
]);



        
[
pool drain
];


        
return
 
0
;


}






-
 
(
NSData
*)
 encryptString
  
NSString
*)
plaintext withKey
  
NSString
*)
key 
{


        
return
 
[[
plaintext dataUsingEncoding
:
NSUTF8StringEncoding
]
 AES256EncryptWithKey
:
key
];


}



-
 
(
NSString
*)
 decryptData
  
NSData
*)
ciphertext withKey
  
NSString
*)
key 
{


        
return
 
[[[
NSString
 alloc
]
 initWithData
:[
ciphertext AES256DecryptWithKey
:
key
]


                                      encoding
:
NSUTF8StringEncoding
]
 autorelease
];


}