I have a C# code, which copy bytes to a byte Array, from specific index, as following example illustrates:
string headerInfo = String.Format(source + "<>" + destination + "<>" + sessionId);
headerInfo = headerInfo.TrimEnd('\n', '\0', '\r');
byte[] headerInfoBytes = Encoding.UTF8.GetBytes(headerInfo);
byte[] headerInfoLength = BitConverter.GetBytes(headerInfo.Length);
//create an byte Array with proper size.
byte[] sendData = new byte[4 + 4 + headerInfoBytes.Length + dataContractBytes.Length];
headerInfoLength.CopyTo(sendData, 0);
dataContractLengthBytes.CopyTo(sendData, 4);
headerInfoBytes.CopyTo(sendData, 8);
dataContractBytes.CopyTo(sendData, 8 + headerInfoBytes.Length);
m_clientSocket.Send(sendData);
my question is, how I can achive the CopyTo in objective c way?
Check out this guide on how to handle mutable data.
If you specifically need the index part, you can use replaceBytesInRange:withBytes:. Otherwise, just append the data:
NSString *headerInfo = [NSString stringWithFormat:#"%#<>%#<>%#", source, destination, sessionId];
NSData *headerData = [headerInfo dataUsingEncoding:NSUTF8StringEncoding];
NSMutableData *data = [NSMutableData dataWithCapacity:headerData.length + ...];
[data appendData:headerData];
Related
I am trying to use c++ api with objc native code in flutter.
https://docs.flutter.dev/development/platform-integration/platform-channels?tab=type-mappings-obj-c-tab
flutter documentation says Uint8List should be stored as FlutterStandardTypedData typedDataWithBytes: in objc do
send argument in flutter
var data = <String, Uint8List>{
"key": byte, //data type is Uint8List
"value": byteBuffer, //data type is Uint8List
};
Uint8List? byteRes;
byteRes = await platform.invokeMethod('SeedDecrypt', data);
get argument in objc (AppDelegate.m)
NSData* key = call.arguments[#"key"];
NSData* value = call.arguments[#"value"];
NSUInteger keyLength = [key length];
NSUInteger valueLength = [value length];
Byte* byteKey = (Byte*)malloc(keyLength);
Byte* byteValue = (Byte*)malloc(valueLength);
memcpy(byteKey, [key bytes], keyLength);
memcpy(byteValue, [value bytes], byteLength);
DWORD roundKey[32];
//Call C++ API
//prototype : void SeedKey(DWORD* roundKey, BYTE* byteKey);
SeedKey(roundKey, byteKey);
//protoType : void Decrypt(BYTE* byteValue, DWORD* roundKey);
Decrypt(byteValue, roundKey);
NSData* res = [NSData dataWithBytes: byteValue length: sizeof(byteValue)];
result(res);
Store the argument as NSData* and copy the memory to a Byte* variable. After executing the C API, it is converted to NSData type. The problem is that when I run it, the device shuts down. I wrote this source referring to the article below. Do you know what my mistake is?
How to convert NSData to byte array in iPhone?
thanks.
Solved
NSNumber* keyLength = call.arguments[#"keyLen"];
NSNumber* valueLength = call.arguments[#"valueLen"];
NSUInteger keyLen = [keyLength integerValue];
NSUInteger valueLen = [valueLength integerValue];
FlutterStandardTypedData* key = call.arguments[#"key"];
FlutterStandardTypedData* value = call.arguments[#"value"];
Byte* byteKey = (Byte*)malloc(keyLen);
Byte* byteValye = (Byte*)malloc(valueLen);
memcpy(byteKey, [key.data bytes], keyLen);
memcpy(byteValue, [value.data bytes], valueLen);
DWORD roundKey[32];
//Call C++ API
NSData* res = [NSData dataWithBytes:keyValue length:keyLen];
FlutterStandardTypedData* rest = [FlutterStandardTypedData typedDataWithBytes: res];
free(byteKey);
free(byteValue);
result(rest);
See https://docs.flutter.dev/development/platform-integration/platform-channels?tab=type-mappings-obj-c-tab. After matching the data type, match the OBJC data type with the C data type and return the result.
I have an NSData object. I need to convert its bytes to a string and send as JSON. description returns hex and is unreliable (according to various SO posters). So I'm looking at code like this:
NSUInteger len = [imageData length];
Byte *byteData = (Byte*)malloc(len);
[imageData getBytes:&byteData length:len];
How do I then send byteData as JSON? I want to send the raw bytes.
CODE:
NSString *jsonBase64 = [imageData base64EncodedString];
NSLog(#"BASE 64 FINGERPRINT: %#", jsonBase64);
NSData *b64 = [NSData dataFromBase64String:jsonBase64];
NSLog(#"Equal: %d", [imageData isEqualToData:b64]);
NSLog(#"b64: %#", b64);
NSLog(#"original: %#", imageData);
NSString *decoded = [[NSString alloc] initWithData:b64 encoding:NSUTF8StringEncoding];
NSLog(#"decoded: %#", decoded);
I get values for everything except for the last line - decoded.
Which would indicate to me that the raw bytes are not formatted in NSUTF8encoding?
The reason the String is being considered 'unreliable' in previous Stack posts is because they too were attempting to use NSData objects where the ending bytes aren't properly terminated with NULL :
NSString *jsonString = [NSString stringWithUTF8String:[nsDataObj bytes]];
// This is unreliable because it may result in NULL string values
Whereas the example below should give you your desired results because the NSData byte string will terminate correctly:
NSString *jsonString = [[NSString alloc] initWithBytes:[nsDataObj bytes] length:[nsDataObj length] encoding: NSUTF8StringEncoding];
You were on the right track and hopefully this is able to help you solve your current problem. Best of luck!
~ EDIT ~
Make sure you are declaring your NSData Object from an image like so:
NSData *imageData = [[NSData alloc] init];
imageData = UIImagePNGRepresentation(yourImage);
Have you tried using something like this:
#implementation NSData (Base64)
- (NSString *)base64EncodedString
{
return [self base64EncodedStringWithWrapWidth:0];
}
This will turn your NSData in a base64 string, and on the other side you just need to decode it.
EDIT: #Lucas said you can do something like this:
NSString *myString = [[NSString alloc] initWithData:myData encoding:NSUTF8StringEncoding];
but i had some problem with this method because of some special characters, and because of that i started using base64 strings for communication.
EDIT3: Trys this method base64EncodedString
#implementation NSData (Base64)
- (NSString *)base64EncodedString
{
return [self base64EncodedStringWithWrapWidth:0];
}
//Helper Method
- (NSString *)base64EncodedStringWithWrapWidth:(NSUInteger)wrapWidth
{
//ensure wrapWidth is a multiple of 4
wrapWidth = (wrapWidth / 4) * 4;
const char lookup[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
long long inputLength = [self length];
const unsigned char *inputBytes = [self bytes];
long long maxOutputLength = (inputLength / 3 + 1) * 4;
maxOutputLength += wrapWidth? (maxOutputLength / wrapWidth) * 2: 0;
unsigned char *outputBytes = (unsigned char *)malloc((NSUInteger)maxOutputLength);
long long i;
long long outputLength = 0;
for (i = 0; i < inputLength - 2; i += 3)
{
outputBytes[outputLength++] = lookup[(inputBytes[i] & 0xFC) >> 2];
outputBytes[outputLength++] = lookup[((inputBytes[i] & 0x03) << 4) | ((inputBytes[i + 1] & 0xF0) >> 4)];
outputBytes[outputLength++] = lookup[((inputBytes[i + 1] & 0x0F) << 2) | ((inputBytes[i + 2] & 0xC0) >> 6)];
outputBytes[outputLength++] = lookup[inputBytes[i + 2] & 0x3F];
//add line break
if (wrapWidth && (outputLength + 2) % (wrapWidth + 2) == 0)
{
outputBytes[outputLength++] = '\r';
outputBytes[outputLength++] = '\n';
}
}
//handle left-over data
if (i == inputLength - 2)
{
// = terminator
outputBytes[outputLength++] = lookup[(inputBytes[i] & 0xFC) >> 2];
outputBytes[outputLength++] = lookup[((inputBytes[i] & 0x03) << 4) | ((inputBytes[i + 1] & 0xF0) >> 4)];
outputBytes[outputLength++] = lookup[(inputBytes[i + 1] & 0x0F) << 2];
outputBytes[outputLength++] = '=';
}
else if (i == inputLength - 1)
{
// == terminator
outputBytes[outputLength++] = lookup[(inputBytes[i] & 0xFC) >> 2];
outputBytes[outputLength++] = lookup[(inputBytes[i] & 0x03) << 4];
outputBytes[outputLength++] = '=';
outputBytes[outputLength++] = '=';
}
if (outputLength >= 4)
{
//truncate data to match actual output length
outputBytes = realloc(outputBytes, (NSUInteger)outputLength);
return [[NSString alloc] initWithBytesNoCopy:outputBytes
length:(NSUInteger)outputLength
encoding:NSASCIIStringEncoding
freeWhenDone:YES];
}
else if (outputBytes)
{
free(outputBytes);
}
return nil;
}
Null termination is not the only problem when converting from NSData to NSString.
NSString is not designed to hold arbitrary binary data. It expects an encoding.
If your NSData contains an invalid UTF-8 sequence, initializing the NSString will fail.
The documentation isn't completely clear on this point, but for initWithData it says:
Returns nil if the initialization fails for some reason (for example
if data does not represent valid data for encoding).
Also: The JSON specification defines a string as a sequence of Unicode characters.
That means even if you're able to get your raw data into a JSON string, parsing could fail on the receiving end if the code performs UTF-8 validation.
If you don't want to use Base64, take a look at the answers here.
All code in this answer is pseudo-code fragments, you need to convert the algorithms into Objective-C or other language yourself.
Your question raises many questions... You start with:
I have an NSData object. I need to convert its bytes to a string and send as JSON. description returns hex and is unreliable (according to various SO posters).
This appears to suggest you wish to encode the bytes as a string, ready to decode them back to bytes the other end. If this is the case you have a number of choices, such as Base-64 encoding etc. If you want something simple you can just encode each byte as its two character hex value, pseudo code outline:
NSMutableString *encodedString = #"".mutableCopy;
foreach aByte in byteData
[encodedString appendFormat:#"%02x", aByte];
The format %02x means two hexadecimal digits with zero padding. This results in a string which can be sent as JSON and decoded easily the other end. The byte size over the wire will probably be twice the byte length as UTF-8 is the recommended encoding for JSON over the wire.
However in response to one of the answer you write:
But I need absolutely the raw bits.
What do you mean by this? Is your receiver going to interpret the JSON string it gets as a sequence of raw bytes? If so you have a number of problems to address. JSON strings are a subset of JavaScript strings and are stored as UCS-2 or UTF-16, that is they are sequences of 16-bit values not 8-bit values. If you encode each byte into a character in a string then it will be represented using 16-bits, if your receiver can access the byte stream it has to skip ever other byte. Of course if you receiver accesses the strings a character at a time each 16-bit character can be truncated back to an 8-bit byte. Now you might think if you take this approach then each 8-bit byte can just be output as a character as part of a string, but that won't work. While all values 1-255 are valid Unicode character code points, and JavaScript/JSON allow NULs (0 value) in strings, not all those values are printable, you cannot put a double quote " into a string without escaping it, and the escape character is \ - all these will need to be encoded into the string. You'd end up with something like:
NSMutableString *encodedString = #"".mutableCopy;
foreach aByte in byteData
if (isprint(aByte) && aByte != '"' && aByte != '\\')
[encodedString appendFormat:#"%c", aByte];
otherwise
[encodedString appendFormat:#"\\u00%02x", aByte]; // JSON unicode escape sequence
This will produce a string which when parsed by a JSON decoder will give you one character (16-bits) for each byte, the top 8-bits being zero. However if you pass this string to a JSON encoder it will encode the unicode escape sequences, which are already encoded... So you really need to send this string over the wire yourself to avoid this...
Confused? Getting complicated? Well why are you trying to send binary byte data as a string? You never say what your high-level goal is or what, if anything, is known about the byte data (e.g. does it represent character in some encoding)
If this is really just an array of bytes then why not send it as JSON array of numbers - a byte is just a number in the range 0-255. To do this you would use code along the lines of:
NSMutableArray *encodedBytes = [NSMutableArray new];
foreach aByte in byteData
[encodedBytes addObject:#(aByte)]; // add aByte as an NSNumber object
Now pass encodedBytes to NSJSONSerialisation and it will send a JSON array of numbers over the wire, the receiver will reverse the process packing each byte back into a byte buffer and you have you bytes back.
This method avoids all issues of valid strings, encodings and escapes.
HTH
I am trying to encrypt a NSString using 3DES with CBC mode encryption on iOS.
Same encryption method is being used on ASP.NET as well and the encrypted string they are getting works with the webservice. The encrypted string for woodcraft554 obtained from .NET code is: 9SWzd+rlvu/tK5UZoCXt8Q==.
.NET is using zero padding for encrytion. The code I am using is:
+(NSString*)new3DESwithoperand:(NSString*)plaintext encryptOrDecrypt:(CCOperation)encryptorDecrypt key:(NSString*)key initVec:(NSString*)initVec
{
NSData* data = [plaintext dataUsingEncoding:NSUTF8StringEncoding];
const void *vplainText = [data bytes];;
size_t plainTextBufferSize = [data length];
NSLog(#"%#, Length: %u",[data description],[data length]);
size_t bufferPtrSize = (plainTextBufferSize + kCCBlockSize3DES) & ~(kCCBlockSize3DES - 1);
NSLog(#"%zu, sizof of uint8_t: %zu",bufferPtrSize, sizeof(uint8_t));
size_t movedBytes = 0;
uint8_t *bufferPtr = malloc( bufferPtrSize * sizeof(uint8_t));
NSLog(#"%zu",sizeof(bufferPtr));
memset((void*)bufferPtr, 0x0, bufferPtrSize);
NSLog(#"%zu",sizeof(bufferPtr));
// memset((void *)initVec, 0x0, (size_t) sizeof(initVec));
const void * vkey = [[NSString base64DataFromString:key] bytes];
const void *vinitVec = [[NSString base64DataFromString:initVec] bytes];
NSLog(#"vinitvec: %#",[[NSString base64DataFromString:initVec] description]);
CCCryptorStatus ccStatus;
ccStatus = CCCrypt(encryptorDecrypt,
kCCAlgorithm3DES,
kCCOptionPKCS7Padding & kCCModeCBC,
vkey,
kCCKeySize3DES,
vinitVec,
vplainText,
plainTextBufferSize,
(void*)bufferPtr,
bufferPtrSize,
&movedBytes);
NSData* result = [NSData dataWithBytes:(const void*)bufferPtr length:(NSUInteger)movedBytes];
NSString* str = [NSString base64StringFromData:result length:result.length];
NSLog(#"%#",str);
return str;
}
I have compared vplainText, vkey and vinitVec from objective-c code to that in .NET. They are same. The encrypted string I am getting is 9SWzd+rlvu8=. I believe it's something to do with padding.
Here is equivalent .NET code they are using:
protected string EncryptCreditCard(string creditCard)
{
try
{
string ENCRYPTION_KEY = ConfigurationManager.AppSettings["ENCRYPTION_KEY"].ToString();
string ENCRYPTION_IV = ConfigurationManager.AppSettings["ENCRYPTION_IV"].ToString();
SymmetricAlgorithm sa = SymmetricAlgorithm.Create("TripleDES");
sa.Key = System.Convert.FromBase64String(ENCRYPTION_KEY);
sa.IV = System.Convert.FromBase64String(ENCRYPTION_IV);
sa.Padding = PaddingMode.Zeros;
byte[] inputByteArray = Encoding.ASCII.GetBytes(creditCard);
MemoryStream mS = new MemoryStream();
ICryptoTransform trans = sa.CreateEncryptor();
byte[] buf = new byte[2048];
CryptoStream cs = new CryptoStream(mS, trans, CryptoStreamMode.Write);
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
return Convert.ToBase64String(mS.ToArray());
}
catch
{
return "";
}
}
How can I get a correct encrypted string in iOS ?
By using zero padding. Your code clearly states kCCOptionPKCS7Padding, which is not zero padding. The cipher text seems identical otherwise.
Note that you are better off using PaddingMode.PKCS7 in your .NET code. It adds some data in the odd case that your plain text is already a number of times the block size in size, but it is standardized and unpadding is not depending on the plain text value anymore.
The issue is with "key" which is used for encryption. iOS uses a 24Byte key while Adnroid and .NET use 16Byte key.
Have posted a detailed solution for the same issue, which depicts key generation. Solution for different encryption value generated in iOS
I'm trying to convert this Javascript code:
self.userSerialEvent = function (join, value, tokens) {
var type = join.charCodeAt(0);
var rawJoin = parseInt(join.substr(1)) - 1;
var rawValue = parseInt(value);
self.SJValues[join] = value;
var payload = "\x00\x00" + String.fromCharCode(value.length + 2) + "\x12" + String.fromCharCode(rawJoin) + value;
self.sendMsg("\x05\x00" + String.fromCharCode(payload.length) + payload);
};
to objective c code for an ipad app.
However I cannot figure out how to properly form this
If I do a char array I cannot have variable length (which will happen when the value is added to the array). And when I try to use NSMutableArray I cant insert bytes, plus my network send operation takes an NSData and I cannot convert a NSMutableArray to data. I have also tried NSString but when I do:
NSString * payload = [NSString stringWithFormat:#"0000%d12%d%#",value.length+2,rawJoin,[value dataUsingEncoding:NSASCIIStringEncoding]];
I get the < > around the data in the string. I have tried to create a character set and remove "<>" from the string but that only removed the end one (leaving the beginning < there)
My question is this: How can I form an array of bytes, that is of variable length and able to convert that array to NSData
Sounds like you are looking for NSMutableData.
NSMutableData *payload = [[NSMutableData alloc] init];
[payload appendBytes:"\000\000" length:2];
uint8_t length = value.length + 2;
[payload appendBytes:&length length:1];
[payload appendBytes:"\022" length:1];
// etc.
I'm trying to compute a key for a SOAP signature using P_SHA-1 defined by WS-Trust. The WS-Trust specification says that
key = P_SHA1 (EntropyFromRequest, EntropyFromResponse)
and the TLS spec says P_SHA-1 is
P_SHA-1(secret, seed) =
HMAC_SHA-1(secret, A(1) + seed) +
HMAC_SHA-1(secret, A(2) + seed) +
HMAC_SHA-1(secret, A(3) + seed) + ...
Where + indicates concatenation.
A() is defined as:
A(0) = seed
A(i) = HMAC_SHA-1(secret, A(i-1))
My algorithm looks like so:
- (NSData*) psha1WithSize:(int)bytes;
{
int numberOfIterations = bytes/16;
NSData *label;
NSData *secret;
NSMutableData *seed;
NSData *reqEntropy = [NSData dataWithBase64EncodedString:requestEntropy];
NSData *resEntropy = [NSData dataWithBase64EncodedString:responseEntropy];
secret = reqEntropy;
seed = resEntropy;
NSData *aIMinusOne = seed;
NSData *aI = nil;
NSMutableData *currentData = [[NSMutableData alloc] init];
for( int i=1; i <= numberOfIterations; i++ )
{
aI = [self hmacSha1Data:aIMinusOne withKey:secret];
NSMutableData *aIPlusSeed = [NSMutableData dataWithData:aI];
[aIPlusSeed appendData:seed];
[currentData appendData:[self hmacSha1Data:aIPlusSeed withKey:secret]];
aIMinusOne = aI;
aI = nil;
}
return currentData;
}
My HMAC looks like these: iPhone and HMAC-SHA-1 encoding
This doesn't seem to be working, and I can't figure out what is wrong with my algorithm. One thought I had was that the service is implemented in .NET WCF, and to get it to accept the hashed password I had to use an NSUTF16LittleEndianStringEncoding, so maybe the response entropy is in the same encoding (prior to base64 encoding)?
Any help is greatly appreciated, thanks.