How to use Java Card API 2.2.2 to implement for ECC p-192 ?

[Harten]

I would like to use Java Card API 2.2.2 to implement for Curve P-192.
In Curve P-192, we have

Code: Select all

p = 62771017353866807638357894232076664160839087\
00390324961279
r = 62771017353866807638357894231760590137671947\
73182842284081
s = 3045ae6f c8422f64 ed579528 d38120ea e12196d5
c = 3099d2bb
bfcb2538 542dcd5f b078b6ef 5f3d6fe2 c745de65
b = 64210519
e59c80e7 0fa7e9ab 72243049 feb8deec c146b9b1
G x = 188da80e
b03090f6 7cbf20eb 43a18800 f4ff0afd 82ff1012
G y = 07192b95
ffc8da78 631011ed 6b24cdd5 73f977a1 1e794811

Then, does anyone tell me how to set Gx, Gy using setG method. which is supported from ECKey.

[UNKNwYSHSA]

The interface ECPrivateKey and ECPublicKey both extens interface ECKey. So you can set Gx uses ECPrivateKey or ECPublicKey. Code as following:

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ECPrivateKey priKey = KeyBuilder.buildKey(KeyBuilder.TYPE_EC_FP_PRIVATE, LENGTH_EC_FP_192, false);
ECPublicKey pubKey = KeyBuilder.buildKey(KeyBuilder.TYPE_EC_FP_PUBLIC, LENGTH_EC_FP_192, false);
pubKey.setA(...);
pubKey.setB(...);
pubKey.setG(...); // Set Gx, Gy here;
pubKey.setXXX(...);
KeyPair kp = new KeyPair(pubKey, priKey);
kp.genKeyPair();
// Next: Use priKey and pubKey ...;

Notice:
1 You shall set EC parameters before genKeyPair;
2 (From description: JavaCard v2.2.2 API javacard.security.KeyPair.genKeyPair)

For the EC case, if the Field, A, B, G and R parameters of the public key object are pre-initialized, then they will be retained. Otherwise default pre-specified values MAY be used (e.g. WAP predefined curves), since computation of random generic EC keys is infeasible on the smart card platform.

(From this description, it seems that it is useful-less to set private key parameters.)