iPhone中的Sqlite数据库保护

Question

我正在开发一个在 sqlite 数据库中存储大量数据的应用程序。但我想保证数据的安全，以免有人入侵我的数据库并查看我数据库中的数据。

现在如何加密和解密我的 sqlite 数据库？

请帮帮我。

谢谢。

Answer 1

我开发了一个需要的应用程序，我一直使用这种方式

首先，我创建了一个类，命名为ConstantMethods.h+m

ConstantMethods.h

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

static NSString *keyEncryption = @"YourPrivateKey";
@interface ConstantMethods : NSObject {

}
+ (NSData*) encryptString:(NSString*)plaintext withKey:(NSString*)key;
+ (NSString*) decryptData:(NSData*)ciphertext withKey:(NSString*)key;

@end

ConstantMethods.m

#import "ConstantMethods.h"

@implementation NSData (AES256)

- (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

@implementation ConstantMethods

+ (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];
}

@end

然后，在您的类中，导入 ConstantMethods.h 并使用该类，如下所示：

[ConstantMethods encryptString:@"yourString"];

当您要解密时，请使用以下命令：

[ConstantMethods decryptData:@"yourString" withKey:keyEncryption];

加密后，将加密后的数据插入数据库，从数据库中取出数据时，解密。

希望对你有帮助。