code

[salvatore]

I'm trying to figure out what is wrong with my decrypt_function,could you have a look at it..

/* Encrypt the buffer in b_to_encrypt */
int encrypt_buffer(char *b_to_encrypt, char *b_encrypted )
{
        gcry_sexp_t data_to_encrypt, data_encrypted;
        gcry_mpi_t mpi_string; 
        int err;
        
        /* i don't really know if it's necessary  */
        memset( b_encrypted,0,MAX_CHARS );

	/* Char ---> MPI */
        if( (err = gcry_mpi_scan( &mpi_string,GCRYMPI_FMT_USG, b_to_encrypt, MAX_CHARS , NULL)) )    
        {
                fprintf(stderr,"Error while converting from char to MPI\n");
                return 0;
        }


        /*  MPI -----> S-exp */
        if( (err = gcry_sexp_build( &data_to_encrypt, NULL, "(data(flags raw)(value %m))",mpi_string)) )  
        {
                fprintf(stderr,"Error while converting from mpi to S-exp\n");
                return 0;
        }

        gcry_mpi_release( mpi_string );        

        /* Encrypt the S-exp with his public key */
        if( (err = gcry_pk_encrypt( &data_encrypted, data_to_encrypt ,key.his_public_key)) )     
        {
                fprintf(stderr,"Error while encrypting\n");
                return 0;
        }

        gcry_sexp_release( data_to_encrypt );             

        /* Convert encrypted S-exp to a valid format so i can send it trought internet (or save in a file) */
        gcry_sexp_sprint(data_encrypted, GCRYSEXP_FMT_CANON, b_encrypted, MAX_CHARS );

         gcry_sexp_release( data_encrypted );

        return 1;
}

/* Decrypt buffer in b_to_decrypt  */
int decrypt_buffer(char *b_to_decrypt, char *b_decrypted, int n_bytes )
{
        gcry_sexp_t data_to_decrypt, data_decrypted;
        gcry_mpi_t mpi_decrypted;
        size_t written; 
        int rc, error_code;

        

        /* Char ---->  S-exp */
        if( (rc = gcry_sexp_sscan(&data_to_decrypt, &error_code, b_to_decrypt, n_bytes )) ) 
        {
                fprintf(stderr,"Error while converting from char to S-exp ");
                return 0;
        }

        /* Decrypt with my private key */
        if( (rc = gcry_pk_decrypt( &data_decrypted, data_to_decrypt, key.my_private_key)) )    
        {
                fprintf(stderr,"Error while decrypting \n");
                return 0;
        }
        gcry_sexp_release( data_to_decrypt );

        /* I think here is the error,because i don't understand how this function work */
        if( (mpi_decrypted = gcry_sexp_nth_mpi( data_decrypted, 0 , GCRYMPI_FMT_USG )) == NULL )   
        {
                fprintf(stderr,"Error while converting from S-exp to mpi \n");
                return 0;
        }

        gcry_sexp_release( data_decrypted );


        /* Convert the decrypted mpi to the original string */
        if( (rc = gcry_mpi_print(GCRYMPI_FMT_USG, b_decrypted, MAX_CHARS , &written, mpi_decrypted ) )) 
        {
                fprintf(stderr,"Error while converting from mpi to char \n");
                return 0;
        }

        gcry_mpi_release( mpi_decrypted );             

        return 1;
}

I don't get any error from neither of these functions but when i display the decrypted buffer it's still encrypted.
Can anybody give me a hint?!

Regards
Salvo