Anyone have any ideas?
Thanks
On Wed, Feb 13, 2008 at 6:44 PM, Joel Christner <[EMAIL PROTECTED]>
wrote:
> Hello,
>
> I have a simple client-server program and am using blowfish. I'm using
> the EVP_* routines to initialize, encrypt, and decrypt. Variable-length
> data is taken in from the client through stdin and sent to the server socket
> after encryption. One question I have is how I clear what's already been
> decrypted on the server-side from the buffer. It appears that the data I've
> already read out of the buffer (post-decryption) is not being discarded,
> thus when data is received, it starts back at the beginning and I get the
> same data back. Any insight would be much appreciated!
>
> On my client side, my code is (simplified)
>
> EVP_EncryptInit(&context,EVP_bf_cbc(),key,iv):
> while(1) {
> fgets(buffer,sizeof(buffer),stdin);
> padBuffer(buffer,paddedBuffer); (my own routine just to pad to length
> that is multiplier of 8-bytes)
> writeBuffer=encrypt(&context,paddedBuffer,strlen(paddedBuffer),&i);
> writeData=sendto(connfd,writeBuffer,strlen(writeBuffer),0,(struct sockaddr
> *)&serveraddress,sizeof(serveraddress));
> }
>
> and on the server side, my code is (simplified):
>
> EVP_DecryptInit(&context,EVP_bf_cbc(),key,iv);
> while(1) {
> dataRead=recvfrom(connfd,readBuffer,sizeof(readBuffer),0,NULL,NULL);
> for (i=0;i<strlen(readBuffer);i++) {
> readBufferClear=decrypt(&context,readBuffer+i,1);
> if (readBufferClear!=0)
> strncat(readBufferFinal,readBufferClear,strlen(readBufferClear));
> }
> unpadBuffer(readBufferFinal,readBufferPadded);
> printf("cleartext=%s\n",readBufferPadded);
> }
>
>
