iOSでファイルをエンコード/デコードする方法

Question

私は多くの方法を試しましたが、htmlファイルを暗号化するための適切な方法が得られていません。

NSString *plainString = @"This string will be encrypted"; 
//should be provided by a user 
NSLog(@"Original String: %@", path); 
NSString *content = [path stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil]; 
NSString *encryptedString = [content dataUsingEncoding:NSUTF8StringEncoding]; 
NSLog(@"Encrypted String: %@", encryptedString); 

Answer 1

NSDATAのサブクラスで新しいクラスを追加します。

クラスの.hファイルにこのコードを貼り付けます。あなたのクラスの.Mファイルに

#import <Foundation/Foundation.h> 

@interface NSData (Encryption) 
- (NSData *)AES256EncryptWithKey:(NSString *)key; 
- (NSData *)AES256DecryptWithKey:(NSString *)key; 
@end 

そして、この：

：

#import "NSData+Encryption.h" 
#import <CommonCrypto/CommonCryptor.h> 

@implementation NSData (Encryption) 
- (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 [NSData 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 [NSData dataWithBytesNoCopy:buffer length:numBytesDecrypted]; 
    } 

    free(buffer); //free the buffer; 
    return nil; 
} 
@end 

は今、このようにHTMLページを暗号化します

NSString * key = @ "YourEncryptionKey"; //ユーザー

 NSLog(@"Original String: %@", htmlCode); 
     NSData *encryptedString = [[htmlCode dataUsingEncoding:NSUTF8StringEncoding] AES256EncryptWithKey:key]; 
     NSLog(@"%@",encryptedString); 

     [encryptedString writeToFile:htmlFilePath atomically:YES]; 
     NSString *myData = [NSString stringWithContentsOfFile:htmlFilePath]; 

     NSLog(@"Data : %@ ",myData); 

さらにとしてファイルを復号化によって提供されている必要があります。 "YourEncryptionKey" @ = *キーをNSStringの

。

NSString *decryptedString= [[NSString alloc] initWithData:[data1 AES256DecryptWithKey:key] encoding:NSUTF8StringEncoding]; 
NSData *utf8Data = [decryptedString dataUsingEncoding:NSUTF8StringEncoding]; 
[utf8Data writeToFile:_pagesPath atomically:YES]; 

NSLog(@"%@",decryptedString); 
NSError* error; 
NSString *htmlContent = [NSString stringWithContentsOfFile:_pagesPath encoding:NSUTF8StringEncoding error:&error]; 

NSData *data = [htmlContent dataUsingEncoding:NSUTF8StringEncoding]; 
NSLog(@"%@",data); 

[_webview loadData:data MIMEType:@"application/xhtml+xml" textEncodingName:@"utf-8" baseURL:[NSURL URLWithString:@""]];