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C# difference between byte[] and char[] format?

I was wondering those differences, since I have a program that asks me for a byte[].
public static string DecryptTextFromFile(String FileName, byte[] Key, byte[]
IV){}
enter image description here
and I have already tried:
char[] key= { '9', 'D', '2', 'A', 'E'}; doesn't give an error but I need byte[]
and this:
byte[] key= { '9', 'D', '2', 'A', 'E'}; // but this one says that I am using char characters, how do I put them in byte[] format?.

You can initialize a byte array like :
byte[] key1 = new byte[] { 57, 68, 50, 65, 69 };
Or convert from Char Array :
char[] keyChars = { '9', 'D', '2', 'A', 'E' };
var key2 = Encoding.ASCII.GetBytes(keyChars);

The char and byte are two different types, char size is 16 bit and byte size is 8 bit;
To represent a char you need to convert to bytes.
To do that you can use BitConverter
char charValue = 'c';
bytep[] bytes = BitConverter.GetBytes(charValue);
To convert your string from the picture you can use this method
static class HexStringConverter
{
public static byte[] ToByteArray(String HexString)
{
int NumberChars = HexString.Length;
byte[] bytes = new byte[NumberChars / 2];
for (int i = 0; i < NumberChars; i += 2)
{
bytes[i / 2] = Convert.ToByte(HexString.Substring(i, 2), 16);
}
return bytes;
}
}
Hope this answer will help you

rewrite c# Stopwatch to c++

I'm rewriting this stopwatch code from C# to C++.
I have rewritten some of the code (I can attach it if you think it's helpful) but confused about the lines after var watch = Stopwatch.StartNew(). Does C++ have similar things like this? What kind of variable type should I put for watch in C++?
namespace BruteForcePasswordGeneration
{
class Program
{
static void Main(string[] args)
{
char[] chars = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
int passwordLength=0;
Console.WriteLine("Enter the password length");
passwordLength = Convert.ToInt32(Console.ReadLine());
BigInteger iPossibilities = (BigInteger)Math.Pow((double)chars.Length, (double)passwordLength);
Console.WriteLine("{0} words total. Press enter to continue;", iPossibilities);
Console.ReadLine();
var watch = Stopwatch.StartNew();
for (BigInteger i = 0; i < iPossibilities; i++)
{
string theword = "";
BigInteger val = i;
for (int j = 0; j < passwordLength; j++)
{
BigInteger ch = val % chars.Length;
theword = chars[(int)ch] + theword;
val = val / chars.Length;
}
Console.WriteLine(theword);
}
watch.Stop();
var elapsedMs = watch.ElapsedMilliseconds;
Console.WriteLine("It took {0} seconds to generate {1} possible combinations", elapsedMs / 1000, iPossibilities);
Console.ReadLine();
}
}
}

Although you can write a "stopwatch" class in C++ if you want, the usual is to just use high_resolution_clock::now() to get the start and stop times. You then use duration_cast to get the difference in the form you want.
If you'll forgive me, I don't see any real point in requiring the user to enter the password length after starting the program. At least to me, it seems easier to use something like "gen_passwords 4" to generate all the passwords of length 4.
That gives code something on this general order:
#include <iostream>
#include <chrono>
#include <string>
int main(int argc, char **argv) {
static const std::string chars{ "ABCDEFGHIJKLMNOPQRSTUVWXYZ" };
if (argc != 2) {
std::cerr << "Usage: generate <password length>\n";
return EXIT_FAILURE;
}
int passwordLength = std::stoi(argv[1]);
unsigned long long iPossibilities = std::pow(chars.size(), passwordLength);
using namespace std::chrono;
auto start = high_resolution_clock::now();
for (unsigned long long i = 0; i < iPossibilities; i++) {
std::string theword;
unsigned long long val = i;
for (int j = 0; j < passwordLength; j++) {
size_t ch = val % chars.size();
theword = chars[ch] + theword;
val /= chars.size();
}
std::cout << theword << '\n';
}
auto stop = high_resolution_clock::now();
double elapsed = duration_cast<milliseconds>(stop - start).count() / 1000.0;
std::cerr << "It took " << elapsed << " seconds to generate " << iPossibilities << " combinations\n";
}

Converting C++ Function to C# (String problems)

I'm trying to convert a code from C++ to C#, but I'm not being able to do it...
std::string Cipher(std::string Str)
{
char Key[5] = { 'H', 'S', 'M', 'K', 'V' };
std::string Encrypted = Str;
for (unsigned int i = 0; i < Str.size(); i++)
{
Encrypted[i] = Str[i] ^ Key[i % (sizeof(Key) / sizeof(char))];
}
return Encrypted;
}
What I got so far in C# is this:
public string Cipher(string Str)
{
char[] Key = new char[5] { 'H', 'S', 'M', 'K', 'V' };
string Encrypted = Str;
for(int i = 0; i < Str.Length; i++)
{
Encrypted[i] = Str[i] ^ Key[i % ((Marshal.SizeOf(Key)) / sizeof(char))]; //line 29
}
return Encrypted;
}
But I keep getting this error:
Property or indexer 'string.this[int]' cannot be assigned to -- it is read only (on line 29)
I found out that it has something to do with immutability of strings, so I tried this:
public string Cipher(string Str)
{
char[] Key = new char[5] { 'H', 'S', 'M', 'K', 'V' };
string Encrypted = Str;
StringBuilder sb = new StringBuilder(Encrypted);
for (int i = 0; i < Str.Length; i++)
{
sb[i] = Str[i] ^ Key[i % ((Marshal.SizeOf(Key)) / sizeof(char))]; //line 30
}
return Encrypted;
}
But, now I get this error:
Cannot implicitly convert type 'int' to 'char'. An explicit conversion exists (are you missing a cast?) (on line 30)
Anyone can help?
Thanks

Close! You are right to use StringBuilder. However, ^ -operator (bitwise XOR) makes C# intepret the result as int. Since you know it's still a char, just add cast:
for (int i = 0; i < Str.Length; i++)
{
sb[i] = (char)(Str[i] ^ Key[i % ((Marshal.SizeOf(Key)) / sizeof(char))]); //line 30
}
Othewise I'm not sure if this does exactly the same as C++ implementation. (sizeof(Key) / sizeof(char) is basically the length of the array. So you should just use Key.length at C# implementation. So a bit more accurate one would be
for (int i = 0; i < Str.Length; i++)
{
sb[i] = (char)(Str[i] ^ Key[i % Key.Length]); //line 30
}

Replace
Encrypted[i] = Str[i] ^ Key[i % ((Marshal.SizeOf(Key)) / sizeof(char))]; //line 29
with
Encrypted[i] = Str[i] ^ Key[i % Key.Lenght]; //line 29
And you can replace characters in a string with:
"1234567890123".Remove(9,1).Insert(9,"A")
Using a string builder is a smarter choice though.

Upload Base64 image string from objective-c to MVC .Net C#

I'm trying to upload a Base64 image string from iOS (using NSData+Base64) to MVC .Net. The upload is ok, but when I try to convert string back to Image, an exception is thrown at line:
byte[] imageBytes = Convert.FromBase64String(imageString);
Exception: "Invalid length for a Base-64 char array"
The imageString length converted in iOS is 944062.
To verify the length, I converted the same image in .Net using
string fota = ImageToBase64(Image.FromFile(#"C:\PR\Source\Servicea\bin\Imag043.jpg"), System.Drawing.Imaging.ImageFormat.Jpeg);
and the size was 203956. And the original image file size is 156,967.
Both methods shouldn't convert the image returning the same string? Anybody had this problem before? Tks
Update: After many tests, I decided to use ASIHTTPRequest lib. Tks all.

Try using this:
#import <CommonCrypto/CommonDigest.h>
#include <stdlib.h>
static char base64EncodingTable[64] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
};
+ (NSString *) base64StringFromData: (NSData *)data length: (int)length {
unsigned long ixtext, lentext;
long ctremaining;
unsigned char input[3], output[4];
short i, charsonline = 0, ctcopy;
const unsigned char *raw;
NSMutableString *result;
lentext = [data length];
if (lentext < 1)
return #"";
result = [NSMutableString stringWithCapacity: lentext];
raw = [data bytes];
ixtext = 0;
while (true) {
ctremaining = lentext - ixtext;
if (ctremaining <= 0)
break;
for (i = 0; i < 3; i++) {
unsigned long ix = ixtext + i;
if (ix < lentext)
input[i] = raw[ix];
else
input[i] = 0;
}
output[0] = (input[0] & 0xFC) >> 2;
output[1] = ((input[0] & 0x03) << 4) | ((input[1] & 0xF0) >> 4);
output[2] = ((input[1] & 0x0F) << 2) | ((input[2] & 0xC0) >> 6);
output[3] = input[2] & 0x3F;
ctcopy = 4;
switch (ctremaining) {
case 1:
ctcopy = 2;
break;
case 2:
ctcopy = 3;
break;
}
for (i = 0; i < ctcopy; i++)
[result appendString: [NSString stringWithFormat: #"%c", base64EncodingTable[output[i]]]];
for (i = ctcopy; i < 4; i++)
[result appendString: #"="];
ixtext += 3;
charsonline += 4;
if ((length > 0) && (charsonline >= length))
charsonline = 0;
}
return result;
}

C# SHA-1 vs. PHP SHA-1...Different Results?

I am trying to calculate a SHA-1 Hash from a string, but when I calculate the string using php's sha1 function I get something different than when I try it in C#. I need C# to calculate the same string as PHP (since the string from php is calculated by a 3rd party that I cannot modify). How can I get C# to generate the same hash as PHP? Thanks!!!
String = s934kladfklada#a.com
C# Code (Generates d32954053ee93985f5c3ca2583145668bb7ade86)
string encode = secretkey + email;
UnicodeEncoding UE = new UnicodeEncoding();
byte[] HashValue, MessageBytes = UE.GetBytes(encode);
SHA1Managed SHhash = new SHA1Managed();
string strHex = "";
HashValue = SHhash.ComputeHash(MessageBytes);
foreach(byte b in HashValue) {
strHex += String.Format("{0:x2}", b);
}
PHP Code (Generates a9410edeaf75222d7b576c1b23ca0a9af0dffa98)
sha1();

Use ASCIIEncoding instead of UnicodeEncoding. PHP uses ASCII charset for hash calculations.

This method in .NET is equivalent to sha1 in php:
string sha1Hash(string password)
{
return string.Join("", SHA1CryptoServiceProvider.Create().ComputeHash(Encoding.UTF8.GetBytes(password)).Select(x => x.ToString("x2")));
}

I had this problem also. The following code will work.
string dataString = "string to hash";
SHA1 hash = SHA1CryptoServiceProvider.Create();
byte[] plainTextBytes = Encoding.ASCII.GetBytes(dataString);
byte[] hashBytes = hash.ComputeHash(plainTextBytes);
string localChecksum = BitConverter.ToString(hashBytes)
.Replace("-", "").ToLowerInvariant();

Had the same problem. This code worked for me:
string encode = secretkey + email;
SHA1 sha1 = SHA1CryptoServiceProvider.Create();
byte[] encodeBytes = Encoding.ASCII.GetBytes(encode);
byte[] encodeHashedBytes = sha1.ComputeHash(passwordBytes);
string pencodeHashed = BitConverter.
ToString(encode HashedBytes).Replace("-", "").ToLowerInvariant();

FWIW, I had a similar issue in Java. It turned out that I had to use "UTF-8" encoding to produce the same SHA1 hashes in Java as the sha1 function produces in PHP 5.3.1 (running on XAMPP Vista).
private static String SHA1(final String text) throws NoSuchAlgorithmException, UnsupportedEncodingException {
final MessageDigest md = MessageDigest.getInstance("SHA-1");
md.update(text.getBytes("UTF-8"));
return new String(org.apache.commons.codec.binary.Hex.encodeHex(md.digest()));
}

Try The following! I think it will work great:
public static string SHA1Encodeb64(string toEncrypt)
{
//Produce an array of bytes which is the SHA1 hash
byte[] sha1Signature = new byte[40];
byte[] sha = System.Text.Encoding.Default.GetBytes(toEncrypt);
SHA1 sha1 = SHA1Managed.Create();
sha1Signature = sha1.ComputeHash(sha);
/**
* The BASE64 encoding standard's 6-bit alphabet, from RFC 1521,
* plus the padding character at the end.
*/
char[] Base64Chars = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/',
'='
};
//Algorithm to encode the SHA1 hash using Base64
StringBuilder sb = new StringBuilder();
int len = sha1Signature.Length;
int i = 0;
int ival;
while (len >= 3)
{
ival = ((int)sha1Signature[i++] + 256) & 0xff;
ival <<= 8;
ival += ((int)sha1Signature[i++] + 256) & 0xff;
ival <<= 8;
ival += ((int)sha1Signature[i++] + 256) & 0xff;
len -= 3;
sb.Append(Base64Chars[(ival >> 18) & 63]);
sb.Append(Base64Chars[(ival >> 12) & 63]);
sb.Append(Base64Chars[(ival >> 6) & 63]);
sb.Append(Base64Chars[ival & 63]);
}
switch (len)
{
case 0: // No pads needed.
break;
case 1: // Two more output bytes and two pads.
ival = ((int)sha1Signature[i++] + 256) & 0xff;
ival <<= 16;
sb.Append(Base64Chars[(ival >> 18) & 63]);
sb.Append(Base64Chars[(ival >> 12) & 63]);
sb.Append(Base64Chars[64]);
sb.Append(Base64Chars[64]);
break;
case 2: // Three more output bytes and one pad.
ival = ((int)sha1Signature[i++] + 256) & 0xff;
ival <<= 8;
ival += ((int)sha1Signature[i] + 256) & 0xff;
ival <<= 8;
sb.Append(Base64Chars[(ival >> 18) & 63]);
sb.Append(Base64Chars[(ival >> 12) & 63]);
sb.Append(Base64Chars[(ival >> 6) & 63]);
sb.Append(Base64Chars[64]);
break;
}
//Encode the signature using Base64
string base64Sha1Signature = sb.ToString();
return base64Sha1Signature;
}