view libtomcrypt/src/pk/dh/dh_export_key.c @ 1638:315fcba6960e

dropbearconvert: keyimport.c: fix BER encoding of secp521r1 keys (#69) keysizes >= 128 octets will be encoded with a 3 byte header which must be accounted by the optional-header Reproduce: master:~/build/dropbear$ ./dropbearkey -t ecdsa -s 521 -f K Generating 521 bit ecdsa key, this may take a while... master:~/build/dropbear$ ./dropbearconvert d o K L Key is a ecdsa-sha2-nistp521 key Wrote key to 'L' master:~/build/dropbear$ openssl ec < L read EC key unable to load Key 139769806448384:error:0D07209B:asn1 encoding routines:ASN1_get_object:too long:crypto/asn1/asn1_lib.c:91:
author Christian Hohnstädt <christian@hohnstaedt.de>
date Wed, 20 Mar 2019 16:42:47 +0100
parents 6dba84798cd5
children
line wrap: on
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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 */

#include "tomcrypt.h"

#ifdef LTC_MDH

/**
  Binary export a DH key to a buffer
  @param out    [out] The destination for the key
  @param outlen [in/out] The max size and resulting size of the DH key
  @param type   Which type of key (PK_PRIVATE or PK_PUBLIC)
  @param key    The key you wish to export
  @return CRYPT_OK if successful
*/
int dh_export_key(void *out, unsigned long *outlen, int type, dh_key *key)
{
   unsigned long len;
   void *k;

   LTC_ARGCHK(out    != NULL);
   LTC_ARGCHK(outlen != NULL);
   LTC_ARGCHK(key    != NULL);

   k = (type == PK_PRIVATE) ? key->x : key->y;
   len = mp_unsigned_bin_size(k);

   if (*outlen < len) {
      *outlen = len;
      return CRYPT_BUFFER_OVERFLOW;
   }
   *outlen = len;

   return mp_to_unsigned_bin(k, out);
}

#endif /* LTC_MDH */

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