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Convert C# to Ruby - MD5 and Base 64 a String

I have this code that I need to convert to ruby, this snippet is to create a security key used for a particular API. The string that I am encrypting is a JSON object.
Should I use Digest::MD5.hexdigest() or Digest::MD5.digest()?
C# Code
string strResponse = "[{\"Key\":\"BookNumber\", \"Value\"=>\"BJAK123\"},{\"Key\"=>\"AuthorCode\", \"Value\"=>\"BNA123\"}]";
using (MD5 md5 = MD5.Create())
{
byte[] bPayload = Encoding.UTF8.GetBytes(strPayload);
byte[] bPayloadHash = md5.ComputeHash(bPayload);
strPayloadBase64 = Convert.ToBase64String(bPayloadHash);
}
Ruby Code
payload = [{"Key"=>"BookNumber", "Value"=>"BJAK123"},{"Key"=>"AuthorCode", "Value"=>"BNA123"}]
utf8_params = payload.to_json.force_encoding("iso-8859-1").force_encoding("utf-8")
payload_base64 = Base64.encode64(Digest::MD5.hexdigest(utf8_params))

Use
payload_base64 = Digest::MD5.base64digest(utf8_params)
as Digest::MD5.hexdigest produces a hex string of digest, whereas C# code is performing base64 encoding of the digest.

PHP MD5 not matching C# MD5

I have a hashing method in C# that looks like:
MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
byte[] raw_input = Encoding.UTF32.GetBytes("hello");
byte[] raw_output = md5.ComputeHash(raw_input);
string output = "";
foreach (byte myByte in raw_output)
output += myByte.ToString("X2");
return output;
How can I implement this in PHP? Doing the following produces a different hash digest...
$output = hash('md5', 'hello');

PHP
This PHP code will do:
<?php
$str = "admin";
$strUtf32 = mb_convert_encoding($str, "UTF-32LE");
echo md5($strUtf32);
?>
This code outputs "1e3fcd02b1547f847cb7fc3add4484a5"

You need to find out which encoding PHP is using to convert your string to text. It's very unlikely that it's using UTF-32. It may well be using the platform default encoding, or possibly UTF-8.
using (MD5 md5 = MD5.Create())
{
byte[] input = Encoding.UTF8.GetBytes("hello");
byte[] hash = md5.ComputeHash(input);
return BitConverter.ToString(hash).Replace("-", "");
}
(This is the problem with languages/platforms which treat strings as binary data all over the place - it doesn't make it clear what's going on. There has to be a conversion to bytes here, as MD5 is defined for bytes, not Unicode characters. In the C# code you're doing it explicitly... in the PHP it's implicit and poorly documented.)
EDIT: If you've got to change the PHP, you could try this:
$text = mb_convert_encoding($text, "UTF-32LE");
$output = md5($text)
It depends whether PHP supports UTF-32 though...

When you apply md5 to Encoding.UTF32.GetBytes("admin");, that's same as
echo hash( "md5","a\0\0\0d\0\0\0m\0\0\0i\0\0\0n\0\0\0");
//1e3fcd02b1547f847cb7fc3add4484a5
In php.
You need to convert your string to UTF32-LE in PHP:
echo md5( mb_convert_encoding( "admin", "UTF-32LE" ) );
//1e3fcd02b1547f847cb7fc3add4484a5

SHA-1 Algorithm in Windows Phone

In my Windows Phone application I need to get hash using SHA-1 Algorithm. How can I do this? For example I have string text="1234";

You would use the SHA1Managed class to compute the hash of a byte array. Probably do something like this:
var sha = new SHA1Managed();
var bytes = System.Text.Encoding.UTF8.GetBytes(text);
byte[] resultHash = sha.ComputeHash(bytes);

SHA1 sha = new SHA1CryptoServiceProvider();
byte[] result = sha.ComputeHash(System.Text.Encoding.UTF8.GetBytes(text));

You should use System.Security.Cryptography.SHA1Managed class.

comparing md5 hashing in android(java) and c#

I am doing md-5 hashing in both android and c# at the same time. But both the results should be the same for the same inputs. Is there any difference in the way its done in both the languages?
I get different outputs in both the cases. Here is the c# code for md-5 calculation:
//this method hashes the values sent to it using MD5
public static String hashwithmd5(String toHashMD5)
{
byte[] keyArray;
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(toHashMD5));
hashmd5.Clear();
return Convert.ToBase64String(keyArray, 0, keyArray.Length);
}
and here is the code for md5 in android using bouncycastle
public byte[] Hashing(String toHash) throws Exception{
byte[] hashBytes = toHash.getBytes("UTF-8");
EditText et = (EditText) findViewById(R.id.entry);
org.bouncycastle.crypto.digests.MD5Digest digest = new org.bouncycastle.crypto.digests.MD5Digest();
digest.reset();
digest.update(hashBytes, 0, hashBytes.length);
int length = digest.getDigestSize();
byte[] md5 = new byte[length];
digest.doFinal(md5, 0);
et.setText(md5.toString());
return md5;
}
the result of md5 in c# is :XUFAKrxLKna5cZ2REBfFkg==
the result of md5 in android is :[B#4053cf40

The C# code converts the hash to Base64, the java code does not. If you convert both raw hashes to e.g. hex strings, they'll be the same.

When you use this in Java:
byte[] md5 = new byte[length];
// ...
md5.toString()
you are not getting a representation of the byte values. You get the generic "string representation" of an object. Here, [B#4053cf40 basically means "array of bytes (that's for the '[B') which internally happens to be at address 4053cf40".
Use android.util.Base64 to convert your bytes to a Base64 encoded string.

#erik is correct. MD5 is no longer considered a "secure" hash; use SHA-256.

Erik is absolutely right. MD5 usage is near extinction, use any strong SHA

How I can encrypt a string in c #?

MD5 md5 = MD5.Create();
byte[] Ostring = System.Text.Encoding.UTF8.GetBytes("original string");
byte[] hashMD5 = md5.ComputeHAsh(Ostring);
StringBuilder sb = new StringBuilder();
for (int i=0; i<hashMD5.Length; i++)
{
sb.Append(hashMD5[i].ToString("X2"));
}
string strMD5 = sb.ToString();
the value of strMD5 I want encrypt it, using the algorithm RSA with a key in DER format "file: aa.key"
How I can do it in c #?

Your code only hashes a string. Hashes are asymmetrical, one-way only - you cannot "unhash" something.
A good, complete example of symmetrical string encryption is here: http://www.obviex.com/samples/Encryption.aspx.

I show an extended example here
The context in this sample was to encrypt a query string using c#