status-im/status-keycard
2
0
Fork 0
mirror of https://github.com/status-im/status-keycard.git synced 2025-02-05 18:33:31 +00:00
Code Issues Projects Releases Wiki Activity

add interface (and possible implementation) for public key derivation from

Browse Source 
private key
This commit is contained in:
Michele Balistreri 2017-10-09 12:37:50 +03:00
parent 3c13025773
commit 3b0319cb37
1 changed files with 22 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
src/main/java/im/status/wallet/ECCurves.java
View File

@ -1,8 +1,12 @@
package im.status.wallet;
import javacard.security.ECKey;
import javacard.security.ECPrivateKey;
import javacard.security.KeyAgreement;
public class ECCurves {
static KeyAgreement ecPointMultiplier;
static final byte SECP256K1_FP[] = {
(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,
(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,(byte)0xFF,
@ -49,4 +53,22 @@ public class ECCurves {
key.setR(SECP256K1_R, (short) 0x00, (short) SECP256K1_R.length);
key.setK(SECP256K1_K);
}
static short derivePublicKey(ECPrivateKey privateKey, byte[] pubOut, short pubOff) {
return multiplyPoint(privateKey, SECP256K1_G, (short) 0, (short) SECP256K1_G.length, pubOut, pubOff);
}
/*
* This might or might not work on actual card. Does not work on simulator. KeyAgreement.ALG_EC_SVDP_DH_PLAIN_XY is actually
* the algorithm we need, but it has been implemented later. However some cards implement KeyAgreement.ALG_EC_SVDP_DH_PLAIN
* in the same way. If we cannot use KeyAgreement to multiply it is difficult to generate public keys on-card.
*/
static short multiplyPoint(ECPrivateKey privateKey, byte[] point, short pointOff, short pointLen, byte[] out, short outOff) {
if (ecPointMultiplier == null) {
ecPointMultiplier = KeyAgreement.getInstance(KeyAgreement.ALG_EC_SVDP_DH_PLAIN, false);
}
ecPointMultiplier.init(privateKey);
return ecPointMultiplier.generateSecret(point, pointOff, pointLen, out, outOff);
}
}