Re: [Opensc-devel] Derive key with opensc

[Douglas E E. <dee...@gm...>]

You may also want to look at NIST 800-56A
http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-56Ar2.pdf

"6 Key Agreement"

In effect a PIV card has a static key pair.
OpenSC derive is just enough to use the key from the card and ECC CDH


http://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-73-4.pdf
"A.5.2.1 ECDH with the PIV KMK"

On 11/10/2015 6:10 AM, klc klc wrote:
> Hi,
>
> I tried to derive key with opensc v14.0 pkcs11-tool on PIV card.
>
> First I generated ec key with openssl using these commands:
>
>   * openssl ecparam -in secp384r1param.pem -genkey -noout -out secp384r1key.pem
>   * openssl ec -in secp384r1key.pem -out secp384r1key.der -pubout -outform der
>   * pkcs11-tool.exe --module opensc-pkcs11.dll --derive -l -pin #### -id 03 -i secp384r1key.der
>
> This gave me error:
>
>   * Cannot open n: m
>
> Which basically says that it can't open the file. [origin: pkcs11-tool->derive_key()->BIO_read_filename(bio_in, opt_input)]
>
> I tried with pem format & it gave me error: Cannot read EC key from secp384r1.pem
>
> My question is
>
>   * whether the format in which I am passing key to opensc is right?
>   * Is there anything else I am missing to provide as an input to tool?
>   * Is my operation correct?
>
> Basically I am trying to write my own application with help of OpenSC implementation to derive a key. Following is the overview of the process I am trying to implement:
>
>   * Application will receive x & y coordinate for EC public key.
>   * Calculated EC key length with help of getEC_POINT() (modified received length as (length - 3) * 8 to adjust to EC key size (in this case 384 bits, I receive 51)).
>   * Generated eckey according to key length with EC_KEY_new by_curve_name(NID_secp384r1) function.
>   * Then called function EC_KEY_generate_key(eckey) function
>   * ecgroup = EC_KEY_get0_group(eckey)
>   * pub = EC_POINT_new(ecgroup)
>   * Converted coordinates to big number with BN_bin2bn() function.
>   * Computed octet string with EC_POINT_point2oct(ecgroup, pub, POINT_CONVERSION_UNCOMPRESSED, str_buf, str_buf_len, NULL). [Please note till this point execution goes successfully & I receive octet
>     string].
>   * Then according to opensc derive_key() function I coded new key template & ECDH parameters. I tried both mechanisms: CKM_ECDH1_COFACTOR_DERIVE, CKM_ECDH1_DERIVE
>   * Till this point everything goes smoothly.
>   * When call to C_DeriveKey() is made I get error as "/Security status not satisfied/" (Login is performed right before derive operation).
>   * Transmitted APDU conforms to the NIST specification: 00 87 14 9D 67 7C 65 82 00 85 61 04 X-coordinate Y-coordinate (48 bytes each).
>   * Received APDU is 69 82.
>
> Also the private key field_length parameter in opensc is set to half of the EC key size. I get 192 bits for 384 bits EC key. Is this right? Is there any other function to retrieve actual value of EC
> key; as now I am modifying received value to drive successful execution (source: pkcs15-sec.c)
>
> I tried to find help on this but to no avail. Can you please guide me on what might be the issue.
>
> PS: I generated EC keys through Charismathics security token configurator & performing derive operation with key Management key.
>
> Thanks,
> K
>
>
> ------------------------------------------------------------------------------
>
>
>
> _______________________________________________
> Opensc-devel mailing list
> Ope...@li...
> https://lists.sourceforge.net/lists/listinfo/opensc-devel
>

-- 

  Douglas E. Engert  <DEE...@gm...>