Convert AES encryption of android in Objective-c xcode

问题

I have to use AES Encryption and decryption similiar to below code

Need to pass similiar data like android did to generate KEY

  package encypt.com;

import java.io.BufferedReader;
import java.io.FileReader;
import java.security.*;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import sun.misc.*;

public class Testing {

private static final String ALGORITHM = "AES";
private static final int ITERATIONS = 2;
private static final byte[] keyValue = 
    new byte[] { 'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y'};

public static String encrypt(String value, String salt) throws Exception {
    Key key = generateKey();
    Cipher c = Cipher.getInstance(ALGORITHM);  
    c.init(Cipher.ENCRYPT_MODE, key);

    String valueToEnc = null;
    String eValue = value;
    for (int i = 0; i < ITERATIONS; i++) {
        valueToEnc = salt + eValue;
        byte[] encValue = c.doFinal(valueToEnc.getBytes());
        eValue = new BASE64Encoder().encode(encValue);
    }
    return eValue;
}

public static String decrypt(String value, String salt) throws Exception {
    Key key = generateKey();
    Cipher c = Cipher.getInstance(ALGORITHM);
    c.init(Cipher.DECRYPT_MODE, key);

    String dValue = null;
    String valueToDecrypt = value;
    for (int i = 0; i < ITERATIONS; i++) {
        byte[] decordedValue = new BASE64Decoder().decodeBuffer(valueToDecrypt);
        byte[] decValue = c.doFinal(decordedValue);
        dValue = new String(decValue).substring(salt.length());
        valueToDecrypt = dValue;
    }
    return dValue;
}

private static Key generateKey() throws Exception {
    Key key = new SecretKeySpec(keyValue, ALGORITHM);
    // SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
    // key = keyFactory.generateSecret(new DESKeySpec(keyValue));
    return key;
}

for iOS i used

 I've found this code through lots of research:

#import "<CommonCrypto/CommonCryptor.h>"
@implementation NSMutableData(AES)

For encryption:

- (NSMutableData*) EncryptAES:(NSString *)key {
    char keyPtr[kCCKeySizeAES256+1];
    bzero( keyPtr, sizeof(keyPtr) );

    [key getCString: keyPtr maxLength: sizeof(keyPtr) encoding: NSUTF16StringEncoding];
    size_t numBytesEncrypted = 0;

    NSUInteger dataLength = [self length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer = malloc(bufferSize);

    NSMutableData *output = [[NSData alloc] init];

    CCCryptorStatus result = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL, [self mutableBytes], [self length], buffer, bufferSize, &numBytesEncrypted);

    output = [NSMutableData dataWithBytesNoCopy:buffer length:numBytesEncrypted];

    if(result == kCCSuccess) {
        return output;
    }
        return NULL;
    }

For Decryption:

- (NSMutableData*)DecryptAES: (NSString*)key andForData:(NSMutableData*)objEncryptedData {

    char  keyPtr[kCCKeySizeAES256+1];
    bzero( keyPtr, sizeof(keyPtr) );

    [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF16StringEncoding];

    size_t numBytesEncrypted = 0;

    NSUInteger dataLength = [self length];

    size_t bufferSize = dataLength + kCCBlockSizeAES128;
    void *buffer_decrypt = malloc(bufferSize);    
    NSMutableData *output_decrypt = [[NSData alloc] init];
    CCCryptorStatus result = CCCrypt(kCCDecrypt , kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL, [self mutableBytes], [self length], buffer_decrypt, bufferSize, &numBytesEncrypted);

    output_decrypt = [NSMutableData dataWithBytesNoCopy:buffer_decrypt length:numBytesEncrypted];

    if(result == kCCSuccess) {
        return output_decrypt;
    } 
        return NULL;
    }
}

This is the code I made that I would like to correspond with the above code:

- (void)Encrypt {
    //Convert NSString to NSData so that it can be used to encrypt the Input
    NSString *Input  = [Inputbox text];
    NSData *InputData = [Input dataUsingEncoding:NSUTF8StringEncoding];
    //What to do here
}

How do I use this code, these methods? Where does it go in my Implementation file? This line near the top says you're adding AES functionality to NSMutableData:

@implementation NSMutableData(AES)

In Objective-C, this is called a category; categories let you extend an existing class.

This code would typically go in a file named NSMutableData-AES.m. Create a header file too, NSMutableData-AES.h. It should contain:

@interface NSMutableData(AES)
- (NSMutableData*) EncryptAES: (NSString *) key;
@end

Include (#import) that header in your main file. Add a call to the encryption function in your code:

NSData *InputData = [Input dataUsingEncoding:NSUTF8StringEncoding];
NSData *encryptedData = [InputData EncryptAES:@"myencryptionkey"];

Similarly for decryption.

BUT i am unable to set keyValue and SALT like android did! Please help

  private static final byte[] keyValue = 
        new byte[] { 'T', 'h', 'i', 's', 'I', 's', 'A', 'S', 'e', 'c', 'r', 'e', 't', 'K', 'e', 'y'};


valueToEnc = salt + eValue;

回答1:

You can use third party library RNCryptor in cocoapods to en/decryption

// Encryption
NSData *data = ...
NSString *password = @"Secret password";
NSData *ciphertext = [RNCryptor encryptData:data password:password];

// Decryption
NSError *error = nil;
NSData *plaintext = [RNCryptor decryptData:ciphertext password:password error:&error];
if (error != nil) {
    NSLog(@"ERROR:%@", error);
    return
}
// ...

来源：https://stackoverflow.com/questions/40485518/convert-aes-encryption-of-android-in-objective-c-xcode