How do you mean, an additional 0 byte is prepended? I generated several DH parameters and exported them to C code ( -C ), some of which has the MSB set. It looks like BN_bin2bn is used directly on the raw bytes of the prime without any padding.
Mike On Tue, Dec 14, 2010 at 12:54 PM, Erik Tkal <et...@juniper.net> wrote: > DER encoding of numeric data should always be network byte order MSB...LSB. > Note that if the high order bit is set then an additional 0 byte is prepended. > > .................................... > Erik Tkal > Juniper OAC/UAC/Pulse Development > > > -----Original Message----- > From: owner-openssl-us...@openssl.org > [mailto:owner-openssl-us...@openssl.org] On Behalf Of Mike Mohr > Sent: Tuesday, December 14, 2010 3:42 PM > To: openssl-users@openssl.org > Subject: Using DH parameters from OpenSSL > > Good afternoon, > > I'm trying to understand the data format that OpenSSL writes out its > DH parameters in. I am aware that the actual data is encoded using > ASN.1 DER and have a way to parse the container. My question really > amounts to byte ordering when DH parameters are generated like this: > > openssl dhparam -outform DER -5 -out parameters.dh 4096 > > Take, for example, the safe prime 'p' in parameters.dh. Are its bytes > stored in MSB...LSB form, such that the number is interpreted > similarly to a human reading base 10 numbers on paper? That is to > say, left to right 1 byte at a time? > > Thanks for any clarification, > Mike > ______________________________________________________________________ > OpenSSL Project http://www.openssl.org > User Support Mailing List openssl-us...@openssl.org > Automated List Manager majord...@openssl.org > ______________________________________________________________________ > OpenSSL Project http://www.openssl.org > User Support Mailing List openssl-us...@openssl.org > Automated List Manager majord...@openssl.org > ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
