Re: RSA private key file problems

[Guillaume JOLIVET]

Thank you for your help, but does someone have any example for signing (RSA with MD5 or RSA with SHA1) a byte buffer using a private key file.

 

 

For the moment, I've got :

AutoSeededRandomPool rng;
   

// Buffer I want to sign

byte* bufferIWantToSign = new byte[16];

memcpy(bufferIWantToSign, "0123456789ABCDEF", 16);

// Private key file
FileSource privFile(<privateKeyFilePath>, true, new HexDecoder());

 

RSASSA_PKCS1v15_MD5_Signer priv(privFile);
  

// Signature length
long lSignedTextLength = priv.SignatureLength();

 

// Create signature buffer 
byte* abySignedBuffer = new byte[lSignedTextLength];

 

// Sign
priv.SignMessage(
      rng, 
      bufferIWantToSign, 
      16,
      abySignedBuffer);

Is this solution correct ? Does abySignedBuffer contain the result of the signature of bufferIWantToSign ? If no, how would you do it.

 

 

 

 

 

 

----- Original Message -----

From: "Shawn Masters" <[EMAIL PROTECTED]>

To: <[EMAIL PROTECTED]>

Sent: Tuesday, July 15, 2003 2:15 PM

Subject: RE: RSA private key file problems

I think the problem may be a little deeper then this.
RSASSA_PKCS1v15_MD5_Signer is not an encryptor, but a signer.  This means it
takes a private key and encrypts the MD5 of the data being signed.  The
PKCS1 defines how the resulting data is formed so it is secure (or atleast
more so then some simpler methods of using RSA) and readable by the
verifier.
To encrypt with RSA you will use a public key, and some symmetric
cipher.  Once you get to that point use debugging methods to look into the
values to make sure that you have loaded all of the correct numbers for the
algorithm chosen.

73,
Shawn

-----Original Message-----
From: Guillaume JOLIVET [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 15, 2003 6:37 AM
To: [EMAIL PROTECTED]
Subject: RSA private key file problems

Hi all,

I would like to crypt data with a RSA with MD5 algorithm but I've got some
problems.
My private key file is a variable-size hexadecimal format file.

Here are my code lines :

FileSource privFile(<myKeyFilePath>, true, new HexDecoder());
RSASSA_PKCS1v15_MD5_Signer priv(privFile);


When I try to crypt, the program fails on the creation of the
RSASSA_PKCS1v15_MD5_Signer object.
I think that the FileSource object is not correct because of the key file
format, but I don't know what kind of object to use instead the HexDecoder
object.


Does somebody got any idea,

Thanks,
Guillaume.