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#include "includes.h"
RCSID("$Id: fingerprint.c,v 1.3 1999/11/24 00:26:01 deraadt Exp $");

#include "ssh.h"
#include "xmalloc.h"

#ifdef HAVE_OPENSSL
#include <openssl/md5.h>
#endif
#ifdef HAVE_SSL
#include <ssl/md5.h>
#endif

#define FPRINT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"

/*
 * Generate key fingerprint in ascii format.
 * Based on ideas and code from Bjoern Groenvall <bg@sics.se>
 */
char *
fingerprint(BIGNUM *e, BIGNUM *n)
{
	static char retval[80];
	MD5_CTX md;
	unsigned char d[16];
	char *buf;
	int nlen, elen;

	nlen = BN_num_bytes(n);
	elen = BN_num_bytes(e);

	buf = xmalloc(nlen + elen);

	BN_bn2bin(n, buf);
	BN_bn2bin(e, buf + nlen);

	MD5_Init(&md);
	MD5_Update(&md, buf, nlen + elen);
	MD5_Final(d, &md);
	snprintf(retval, sizeof(retval), FPRINT,
	    d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7],
	    d[8], d[9], d[10], d[11], d[12], d[13], d[14], d[15]);
	memset(buf, 0, nlen + elen);
	xfree(buf);
	return retval;
}