I am supplied the following RSA private key in the format
<RSAKeyValue>
<Modulus>XXXXXXXX</Modulus>
<Exponent>XXXXXXXX</Exponent>
<P>XXXXXXXX</P>
<Q>XXXXXXXX</Q>
<DP>XXXXXXXX</DP>
<DQ>XXXXXXXX</DQ>
<InverseQ>XXXXXXXXXX/InverseQ>
<D>XXXXXXXX</D>
</RSAKeyValue>
The XXXX are in Base64 format.
I want to know how to combine it all the XXXXXX bits to a single Base64 string.
With this single Base64 string i do the following:
1. Feed it to a TMemorStream
2. use Indy's TIdDecoderMIME class to decode Base64 from the MemoryStream
3. The decoded MemoryStream is then feed into CryptDecrypt function from wcrypt2.pas (a delphi wrapper of Microsoft's Cryptographic API) from Jedi
I know the solution for public key in the same format
<RSAKeyValue>
<Modulus>xqiYKv0umaLdmrKPyBfYmAfzZYVsvsOJyS4c1lBPjqpn7zh+XyxPXK7MxJkAlenQJM33M+ZYfmlPLya7JWXXTPviylEEtlmul9GshpX2caxWu2YO9vNIHRZYYau4ccbkm95iMyJi8KN2ANtqDwiJv55vcXZDqjPSDE4ap49xmog==</Modulus>
<Exponent>AAQC</Exponent>
</RSAKeyValue>
The solution is to add "BgIAAACkAABSU0ExAAQAAAE" + Exponent + Modulus
The result is:
BgIAAACkAABSU0ExAAQAAAEAAQCxqiYKv0umaLdmrKPyBfYmAfzZYVsvsOJyS4c1lBPjqpn7zh+XyxPXK7MxJkAlenQJM33M+ZYfmlPLya7JWXXTPviylEEtlmul9GshpX2caxWu2YO9vNIHRZYYau4ccbkm95iMyJi8KN2ANtqDwiJv55vcXZDqjPSDE4ap49xmog==
With the private key how do we combine it? I know it starts off like this:
"BwIAAACkAABSU0ExAAQAAAE" + Exponent + Modulus + ???????
The XXXX in the RSAKeyValue XML are in base64, just that i do not want to expose the details there. I want to know how do i combine all the XXXX base64 codes into a single base64 private key.
I suspect that this means that you are performing the base64 encoding line by line. It's much simpler to perform the encoding on the entire file.
For example you might do this as follows:
Load the file into a TStringList.
Extract a single string representing the file using the Text property of the string list.
Base64 encode that string.
Send it over the wire.
At the receiving end, decode the string.
Assign the string to the Text property of a string list.
Related
I have hex value which contain email id as UTF8 string like :
30440C17726F6869746B616C6538353231407961686F6F2E636F6D180F32303232303932393131303234395A0C05656D61696C060B6086480186FD1E0101020702020C000C00
How do I decode and get email id using OpenSSL in iOS objective-C / C ?
I can able to decode using online Hex to ANS1 decoder
Output come as:
SEQUENCE {
UTF8String 'rohitkale8521#yahoo.com'
GeneralizedTime '20220929110249Z'
UTF8String 'email'
OBJECTIDENTIFIER 2.16.840.1.114334.1.1.2.7
INTEGER 0x0C00 (3072 decimal)
UTF8String ''
}
To decode API response string to JSON, json.decode() works fine.
This will parse a JSON string similar to
{ "Response" : {"Responsecode" : "1" , "Response" : "Success"}}
But in my case, the response comes in the serialized form like:
{\"Response\" : {\"Responsecode\" : \"0\" , \"Response\" : \"Success\"}}
json.decode() won’t work.
In Java, I used StringEscapeUtils.unescapeJson() for the same problem.
I searched for Dart but couldn’t find how to unescape characters in a string.
Edit:
Suppose, the value of key data is abc"de
So, its corresponding JSON would be {"data":"abc\"de"}
And hence during serialization, this json string is escaped to give {\"data\":\"abc\\\"de\"} as the response, which is sent by the API.
So, my intention is to remove the escape sequences, so that I can get the string {"data":"abc\"de"}, which would later be decoded using json.decode(). Removing the escape sequences was done using StringEscapeUtils.unescapeJson() in java.
json.decode can decode single strings too, so you should be able to just call it twice. The first time it'll return you a string (where the escape characters have been decoded) and the second time it'll decode that string into the map:
import 'dart:convert';
void main() {
var a = r'''"{\"Response\" : {\"Responsecode\" : \"0\" , \"Response\" : \"Success\"}}"''';
var b = json.decode(json.decode(a));
print(b['Response']['Responsecode']); // 0
print(b['Response']['Response']); // Success
}
I have to write a program to establish a secure communication with a USB device. I have to use the private key generated from it which is stored in PKCS#1 format. As I have used Crypto++ in order part of my program, I would like to utilize it for this purpose as well.
However, I cannot find a way to import RSA private key from memory. It accepts private key in PKCS#8 format only. Could some pro show me a sample code on how to do it? Many thanks!
PKCS#1 format is ASN.1 encoded. For RSAPublicKey and RSAPrivateKey, its as easy as:
RSA::PublicKey publicKey(...);
ByteQueue queue;
publicKey.Save(queue);
// The public key is now in the ByteQueue in PKCS #1 format
// ------------
// Load a PKCS #1 private key
byte key[] = {...}
ArraySource arr(key, sizeof(key));
RSA::PrivateKey privateKey;
privateKey.Load(arr);
// The private key is now ready to use
Saving and loading keys is discussed in more detail at the Crypto++ wiki under Keys and Formats.
I'm having a problem with UTF8 encoding in my asp.net mvc 2 application in C#. I'm trying let user download a simple text file from a string. I am trying to get bytes array with the following line:
var x = Encoding.UTF8.GetBytes(csvString);
but when I return it for download using:
return File(x, ..., ...);
I get a file which is without BOM so I don't get Croatian characters shown up correctly. This is because my bytes array does not include BOM after encoding. I triend inserting those bytes manually and then it shows up correctly, but that's not the best way to do it.
I also tried creating UTF8Encoding class instance and passing a boolean value (true) to its constructor to include BOM, but it doesn't work either.
Anyone has a solution? Thanks!
Try like this:
public ActionResult Download()
{
var data = Encoding.UTF8.GetBytes("some data");
var result = Encoding.UTF8.GetPreamble().Concat(data).ToArray();
return File(result, "application/csv", "foo.csv");
}
The reason is that the UTF8Encoding constructor that takes a boolean parameter doesn't do what you would expect:
byte[] bytes = new UTF8Encoding(true).GetBytes("a");
The resulting array would contain a single byte with the value of 97. There's no BOM because UTF8 doesn't require a BOM.
I created a simple extension to convert any string in any encoding to its representation of byte array when it is written to a file or stream:
public static class StreamExtensions
{
public static byte[] ToBytes(this string value, Encoding encoding)
{
using (var stream = new MemoryStream())
using (var sw = new StreamWriter(stream, encoding))
{
sw.Write(value);
sw.Flush();
return stream.ToArray();
}
}
}
Usage:
stringValue.ToBytes(Encoding.UTF8)
This will work also for other encodings like UTF-16 which requires the BOM.
UTF-8 does not require a BOM, because it is a sequence of 1-byte words. UTF-8 = UTF-8BE = UTF-8LE.
In contrast, UTF-16 requires a BOM at the beginning of the stream to identify whether the remainder of the stream is UTF-16BE or UTF-16LE, because UTF-16 is a sequence of 2-byte words and the BOM identifies whether the bytes in the words are BE or LE.
The problem does not lie with the Encoding.UTF8 class. The problem lies with whatever program you are using to view the files.
Remember that .NET strings are all unicode while there stay in memory, so if you can see your csvString correctly with the debugger the problem is writing the file.
In my opinion you should return a FileResult with the same encoding that the files. Try setting the returning File encoding,
I have a site where I allow members to upload photos. In the MVC Controller I take the FormCollection as the parameter to the Action. I then read the first file as type HttpPostedFileBase. I use this to generate thumbnails. This all works fine.
In addition to allowing members to upload their own photos, I would like to use the System.Net.WebClient to import photos myself.
I am trying to generalize the method that processes the uploaded photo (file) so that it can take a general Stream object instead of the specific HttpPostedFileBase.
I am trying to base everything off of Stream since the HttpPostedFileBase has an InputStream property that contains the stream of the file and the WebClient has an OpenRead method that returns Stream.
However, by going with Stream over HttpPostedFileBase, it looks like I am loosing ContentType and ContentLength properties which I use for validating the file.
Not having worked with binary stream before, is there a way to get the ContentType and ContentLength from a Stream? Or is there a way to create a HttpPostedFileBase object using the Stream?
You're right to look at it from a raw stream perspective because then you can create one method that handles streams and therefore many scenarios from which they come.
In the file upload scenario, the stream you're acquiring is on a separate property from the content-type. Sometimes magic numbers (also a great source here) can be used to detect the data type by the stream header bytes but this might be overkill since the data is already available to you through other means (i.e. the Content-Type header, or the .ext file extension, etc).
You can measure the byte length of the stream just by virtue of reading it so you don't really need the Content-Length header: the browser just finds it useful to know what size of file to expect in advance.
If your WebClient is accessing a resource URI on the Internet, it will know the file extension like http://www.example.com/image.gif and that can be a good file type identifier.
Since the file info is already available to you, why not open up one more argument on your custom processing method to accept a content type string identifier like:
public static class Custom {
// Works with a stream from any source and a content type string indentifier.
static public void SavePicture(Stream inStream, string contentIdentifer) {
// Parse and recognize contentIdentifer to know the kind of file.
// Read the bytes of the file in the stream (while counting them).
// Write the bytes to wherever the destination is (e.g. disk)
// Example:
long totalBytesSeen = 0L;
byte[] bytes = new byte[1024]; //1K buffer to store bytes.
// Read one chunk of bytes at a time.
do
{
int num = inStream.Read(bytes, 0, 1024); // read up to 1024 bytes
// No bytes read means end of file.
if (num == 0)
break; // good bye
totalBytesSeen += num; //Actual length is accumulating.
/* Can check for "magic number" here, while reading this stream
* in the case the file extension or content-type cannot be trusted.
*/
/* Write logic here to write the byte buffer to
* disk or do what you want with them.
*/
} while (true);
}
}
Some useful filename parsing features are in the IO namespace:
using System.IO;
Use your custom method in the scenarios you mentioned like so:
From an HttpPostedFileBase instance named myPostedFile
Custom.SavePicture(myPostedFile.InputStream, myPostedFile.ContentType);
When using a WebClient instance named webClient1:
var imageFilename = "pic.gif";
var stream = webClient1.DownloadFile("http://www.example.com/images/", imageFilename)
//...
Custom.SavePicture(stream, Path.GetExtension(imageFilename));
Or even when processing a file from disk:
Custom.SavePicture(File.Open(pathToFile), Path.GetExtension(pathToFile));
Call the same custom method for any stream with a content identifer that you can parse and recognize.