AES加密（oc实现）

AES加密（oc实现）

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NSData+Encryption.h 文件：

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

@interface NSData(Encryption)

- (NSData *)AES256EncryptWithKey:(NSString *)key;   //加密
- (NSData *)AES256DecryptWithKey:(NSString *)key;   //解密

@end

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NSData+Encryption.m文件：

#import "NSData+Encryption.h"
@implementation NSData (Encryption) 

//这里AES在iOS加过密以后以nsdata的形式存下来，如果想以nsstring形式存储，那么对nsdata进行base64位编码。
- (NSData *)AES256EncryptWithKey:(NSString *)key {//加密
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;
}


- (NSData *)AES256DecryptWithKey:(NSString *)key {//解密
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;
}

@end