Implementing AES256 on iOS using CCCrypt function. But output and output buffer length is different than Android.
Cipher class in Android produces 48 bytes data where in iOS we get 80 bytes data.
In IOS using kCCAlgorithmAES, kCCOptionPKCS7Padding and in android using AES/CBC/PKCS5Padding.
in IOS IV is NULL and in android creating iv as new 16 bytes array.
Please help.
please find input and code for reference.
- (void)viewDidLoad {
[super viewDidLoad];
NSString *message = [NSString stringWithFormat:@"com.myapp.com|355004059196637|911111111111|11341e5e-9643-4559-bbb7-34d40555e96c"];
NSString *key = [NSString stringWithFormat:@"4f28d5901b4b7b80d33fda76ca372c2a20bd1a6c2aad7fa215dc79d507330678"];
NSString *shaEncryptMessage = [self sha256:message length:0];
NSData *aesEncryptData = [self aesEncrypt:[shaEncryptMessage dataUsingEncoding:NSUTF8StringEncoding] key:key iv:nil];
NSString *hMac = [aesEncryptData base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
NSLog(@"hMac = %@",hMac);
// IOS output : Can+oQR79D3/lsQGctzY/d2VBNZbWWtJxGI8iRIu80R2yTskn9gf2oKHaRESX73u
// LpJHLx1Xr6iH11jFPlmqwW7mQz0xAW4uACNAMEoZ0kY=
// Android output : MiMDkdo5cGsPMj2qCnNobgp7dr5KMvBhGuKTonrqr1lCYte/kKegGMtI/4TPhUNI
}
- (NSString*) sha256:(NSString *)key length:(NSInteger) length{
const char *s=[key cStringUsingEncoding:NSASCIIStringEncoding];
NSData *keyData=[NSData dataWithBytes:s length:strlen(s)];
uint8_t digest[CC_SHA256_DIGEST_LENGTH]={0};
CC_SHA256(keyData.bytes, (unsigned int)keyData.length, digest);
NSData *out=[NSData dataWithBytes:digest length:CC_SHA256_DIGEST_LENGTH];
NSString *hash=[out description];
hash = [hash stringByReplacingOccurrencesOfString:@" " withString:@""];
hash = [hash stringByReplacingOccurrencesOfString:@"<" withString:@""];
hash = [hash stringByReplacingOccurrencesOfString:@">" withString:@""];
return hash;
}
- (NSData *)aesEncrypt:(NSData *)plainText key:(NSString *)key iv:(NSString *)iv {
char keyPointer[kCCKeySizeAES256+2],// room for terminator (unused) ref: https://devforums.apple.com/message/876053#876053
ivPointer[kCCBlockSizeAES128];
BOOL patchNeeded;
bzero(keyPointer, sizeof(keyPointer)); // fill with zeroes for padding
//key = [[StringEncryption alloc] md5:key];
key = [self stringFromHex:key];
patchNeeded= ([key length] > kCCKeySizeAES256+1);
if(patchNeeded)
{
key = [key substringToIndex:kCCKeySizeAES256]; // Ensure that the key isn't longer than what's needed (kCCKeySizeAES256)
}
[key getCString:keyPointer maxLength:sizeof(keyPointer) encoding:NSUTF8StringEncoding];
[iv getCString:ivPointer maxLength:sizeof(ivPointer) encoding:NSUTF8StringEncoding];
// if (patchNeeded) {
// keyPointer[0] = '\0'; // Previous iOS version than iOS7 set the first char to '\0' if the key was longer than kCCKeySizeAES256
// }
NSUInteger dataLength = [plainText length];
// For block ciphers, the output size will always be less than or equal to the input size plus the size of one block.
size_t buffSize = dataLength + kCCBlockSizeAES128;
void *buff = malloc(buffSize);
size_t numBytesEncrypted = 0;
CCCryptorStatus status = CCCrypt(kCCEncrypt, /* kCCEncrypt, etc. */
kCCAlgorithmAES128, /* kCCAlgorithmAES128, etc. */
kCCOptionPKCS7Padding, /* kCCOptionPKCS7Padding, etc. */
keyPointer, kCCKeySizeAES256, /* key and its length */
NULL, /* initialization vector - use random IV everytime */
[plainText bytes], [plainText length], /* input */
buff, buffSize,/* data RETURNED here */
&numBytesEncrypted);
if (status == kCCSuccess) {
return [NSData dataWithBytesNoCopy:buff length:numBytesEncrypted];
}
free(buff);
return nil;
}
- (NSString *) stringFromHex:(NSString *)str
{
NSMutableData *stringData = [[NSMutableData alloc] init];
unsigned char whole_byte;
char byte_chars[3] = {'\0','\0','\0'};
int i;
for (i=0; i < [str length] / 2; i++) {
byte_chars[0] = [str characterAtIndex:i*2];
byte_chars[1] = [str characterAtIndex:i*2+1];
whole_byte = strtol(byte_chars, NULL, 16);
[stringData appendBytes:&whole_byte length:1];
}
return [[NSString alloc] initWithData:stringData encoding:NSASCIIStringEncoding];
}
Please find android code also,
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
generateHMAC();
}
String K0 = "4f28d5901b4b7b80d33fda76ca372c2a20bd1a6c2aad7fa215dc79d507330678";
String generatedString = "com.myapp.com|355004059196637|911111111111|11341e5e-9643-4559-bbb7-34d40555e96c";
private void generateHMAC() {
Log.d("Message of Hash", generatedString);
byte[] var14 = new byte[0];
try {
var14 = SHA256(generatedString);
byte[] var15 = new byte[0];
var15 = encrypt(var14, hexStringToByteArray(K0));
String var4 = Base64.encodeToString(var15, 2);
Log.d("Existing K0", K0);
Log.d("HMAC", var4);
} catch (Exception e) {
e.printStackTrace();
}
}
public byte[] SHA256(String paramString) throws Exception {
MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update(paramString.getBytes("UTF-8"));
byte[] digest = md.digest();
return digest;
}
public byte[] encrypt(byte[] var1, byte[] var2) throws Exception {
SecretKeySpec var3 = new SecretKeySpec(var2, "AES");
byte[] var4 = new byte[16];
IvParameterSpec var5 = new IvParameterSpec(var4);
Cipher var6 = Cipher.getInstance("AES/CBC/PKCS5Padding");
var6.init(1, var3, var5);
byte[] var7 = var6.doFinal(var1);
return var7;
}
public byte[] hexStringToByteArray(String var1) {
byte[] var2 = new byte[var1.length() / 2];
for (int var3 = 0; var3 < var2.length; ++var3) {
int var4 = var3 * 2;
int var5 = Integer.parseInt(var1.substring(var4, var4 + 2), 16);
var2[var3] = (byte) var5;
}
return var2;
}