> 2. One more thing that I'm missing right now - which params should I store
> in NameValuePairs?
>
> I guess for:
> - deriviation they should be at least: null sault, info string Android
> encoded in Ascii.
>
This looks like what you need for the KDF:
template <class H>
class AndroidPay_KDF
{
public:
static void CRYPTOPP_API DeriveKey(byte *output, size_t outputLength,
const byte *input, size_t inputLength,
const byte *derivationParams, size_t derivationParamsLength)
{
CRYPTOPP_UNUSED(derivationParams),
CRYPTOPP_UNUSED(derivationParamsLength);
static const byte INFO[] = "Android";
static const size_t INFO_SIZE = 7;
HKDF<H> hkdf;
hkdf.DeriveKey(output, outputLength, input, inputLength, NULL, 0,
INFO, INFO_SIZE);
}
};
> - encryption algo: zero IV and no padding
>
>
This will probably be specified in the Encryption Algorithm (EA) to the
Discrete Log Encryption Scheme (DL_ES). For ECIES
(https://www.cryptopp.com/docs/ref/struct_e_c_i_e_s.html), that is:
DL_EncryptionAlgorithm_Xor
Here's the full view of ECIES
(http://www.cryptopp.com/docs/ref/eccrypto_8h_source.html#l00284):
289 template <class EC, class COFACTOR_OPTION = NoCofactorMultiplication,
bool DHAES_MODE = false>
290 struct ECIES
291 : public DL_ES<
292 DL_Keys_EC<EC>,
293 DL_KeyAgreementAlgorithm_DH<typename EC::Point, COFACTOR_OPTION>,
294 DL_KeyDerivationAlgorithm_P1363<typename EC::Point, DHAES_MODE,
P1363_KDF2<SHA1> >,
295 DL_EncryptionAlgorithm_Xor<HMAC<SHA1>, DHAES_MODE>,
296 ECIES<EC> >
297 {
298 static std::string CRYPTOPP_API StaticAlgorithmName() {return "ECIES";}
...
305 };
We'll still need to map Android Pay specs to ECIES terminology, like
Cofactor Options and DHAES_MODE. Some of this has been documented in
Crypto++, like COFACTOR_OPTIONS
(http://www.cryptopp.com/docs/ref/pubkey_8h.html#ae4b59f7b9d3c7e03bb739f0584905ff1).
See, for example, "Methods for Avoiding the "Small-Subgroup" Attacks on the
Diffie-Hellman Key Agreement Method", http://tools.ietf.org/html/rfc2785.
I'm not familiar with other terminology like CheckMode and SingleHashMode,
but I believe the answer lies in the implementation of the algorithm. Once
you get there, it will be obvious what they meant.
Jeff
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