HI for ECDH can I use the HAs256 algorithm.
I have gone through the inside DS and written this piece of code and
it worked also.
But here how can U sesha256 ,when i used i am getting the error.
How can i use here sha256?
int alen = 0;
int blen = 0;
int aout = 0;
int bout = 0;
static const int KDF1_SHA1_len = 20;
unsigned char *abuf = NULL;
unsigned char *bbuf = NULL;
EC_KEY *ecdh = NULL;
EC_KEY *ecdh2 = NULL;
//Generate Public
// ecdh = EC_KEY_new_by_curve_name(NID_secp521r1);
// ecdh2 = EC_KEY_new_by_curve_name(NID_secp521r1);
ecdh = EC_KEY_new_by_curve_name((NID_sect163k1));
ecdh2 = EC_KEY_new_by_curve_name(NID_sect163k1);
EC_KEY_generate_key(ecdh);
EC_KEY_generate_key(ecdh2);
alen = KDF1_SHA1_len;
abuf = (unsigned char *) OPENSSL_malloc (alen);
aout = ECDH_compute_key(abuf, alen, EC_KEY_get0_public_key(ecdh2),
ecdh, KDF1_SHA1);
printf("aout is %d\n",aout);
blen = KDF1_SHA1_len;
bbuf = (unsigned char *)OPENSSL_malloc(blen);
bout = ECDH_compute_key(bbuf, blen, EC_KEY_get0_public_key(ecdh),
ecdh2, KDF1_SHA1);
On 17 December 2012 20:15, jeetendra gangele <gangele...@gmail.com> wrote:
> I need to use ECDH to derive the shared key using public and private key
> given.
>
>
>
> On 17 December 2012 18:56, jeetendra gangele <gangele...@gmail.com> wrote:
>> Thanks for ur help .
>>
>>
>> Can you guide me how can I use ECDH for exachnaging of the secret key.
>> I have to implement in two phases.
>> 1.i have private key of 256 bit lenght need to get phase i1 value wx,wy
>> 2.In second I have phase1 value and private key and need to get secret
>> key or public key.
>>
>>
>>
>> Thanks
>>
>>
>> On 17 December 2012 13:55, Dave Thompson <dthomp...@prinpay.com> wrote:
>>>> From: owner-openssl-us...@openssl.org On Behalf Of jeetendra gangele
>>>> Sent: Monday, 17 December, 2012 02:48
>>>
>>>> Yes i am talking about signature.
>>>> ECDSA_SIG this ouptput structure will have r and s componet
>>>> of 28 bytes each. [for 224-bit curve]
>>>> So if I merge both r and s I will get 56 bytes right?
>>>> These will not have any padding information?.
>>>>
>>> The struct points to two bignums, which use an internal
>>> format; openssl can put what it likes in there.
>>> If you get the (near-trivial) encoding as big-endian btyes
>>> using BN_bn2bin, *that* does not have padding or overhead.
>>>
>>> Note that the numbers in an ECDSA signature are effectively
>>> uniform random up to the field order, so they will *rarely*
>>> be *smaller* than the keysize (here, less then 28 bytes).
>>> If you want *fixed* 28 bytes each, *you* will need to pad.
>>>
>>> (I forgot to allow for this in my earlier reply. The ASN.1
>>> encoding can be less than 62 bytes in these cases.)
>>>
>>> ______________________________________________________________________
>>> OpenSSL Project http://www.openssl.org
>>> User Support Mailing List openssl-users@openssl.org
>>> Automated List Manager majord...@openssl.org
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