# Would a question regarding a specific crypto library be on topic @ crypto.SE?

For example, would a question asking what the Blowfish structure BLOWFISH_CTX or the variables xl and xr do in the following header does be on topic here?

/*

Copyright (C) 1997 by Paul Kocher

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
version 2.1 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

typedef struct {
unsigned long P[16 + 2];
unsigned long S[4][256];
} BLOWFISH_CTX;

void Blowfish_Init(BLOWFISH_CTX *ctx, unsigned char *key, int keyLen);
void Blowfish_Encrypt(BLOWFISH_CTX *ctx, unsigned long *xl, unsigned long *xr);
void Blowfish_Decrypt(BLOWFISH_CTX *ctx, unsigned long *xl, unsigned long *xr);


Or would that belong at SO or CR.SE?

• Please ask programming related on SO. Crypto.SE focuses on the mathematical models behind cryptography. – Hendrik Brummermann Aug 30 '13 at 20:58
• @HendrikBrummermann That's why I thought that more people at Crypto.SE might know about what xl and xr are supposed to be. – haneefmubarak Aug 31 '13 at 6:49