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remove one memory copy operation

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Michele Balistreri 2020-06-23 10:30:50 +03:00
parent a1c2bc119d
commit 37dd4aca69
No known key found for this signature in database
GPG Key ID: E9567DA33A4F791A
1 changed files with 17 additions and 18 deletions
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35
src/main/java/im/status/keycard/SECP256k1.java
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@ -65,12 +65,12 @@ public class SECP256k1 {
static final short SCHNORR_K_OUT_OFF = (short) 0;
static final short SCHNORR_E_OUT_OFF = (short) (SECP256K1_BYTE_SIZE + SCHNORR_K_OUT_OFF);
static final short SCHNORR_D_OUT_OFF = (short) (SCHNORR_COMPONENT_SIZE + SCHNORR_E_OUT_OFF);
static final short SCHNORR_TMP1_OUT_OFF = (short) (SCHNORR_COMPONENT_SIZE + SCHNORR_D_OUT_OFF);
static final short SCHNORR_RES_OUT_OFF = (short) (SCHNORR_COMPONENT_SIZE + SCHNORR_D_OUT_OFF);
static final short SCHNORR_E_32_OFF = (short) (SCHNORR_COMPONENT_SIZE - SECP256K1_BYTE_SIZE + SCHNORR_E_OUT_OFF);
static final short SCHNORR_D_32_OFF = (short) (SCHNORR_COMPONENT_SIZE - SECP256K1_BYTE_SIZE + SCHNORR_D_OUT_OFF);
static final short SCHNORR_TMP1_32_OFF = (short) (SCHNORR_COMPONENT_SIZE - SECP256K1_BYTE_SIZE + SCHNORR_TMP1_OUT_OFF);
static final short SCHNORR_TMP1_64_OFF = (short) (SCHNORR_COMPONENT_SIZE - SCHNORR_S_OUT_SIZE + SCHNORR_TMP1_OUT_OFF);
static final short SCHNORR_RES_32_OFF = (short) (SCHNORR_COMPONENT_SIZE - SECP256K1_BYTE_SIZE + SCHNORR_RES_OUT_OFF);
static final short SCHNORR_RES_64_OFF = (short) (SCHNORR_COMPONENT_SIZE - SCHNORR_S_OUT_SIZE + SCHNORR_RES_OUT_OFF);
static final short TMP_LEN = (short) (SECP256K1_BYTE_SIZE + (SCHNORR_COMPONENT_SIZE * 3));
@ -182,27 +182,26 @@ public class SECP256k1 {
crypto.sha256.doFinal(data, dataOff, dataLen, tmp, SCHNORR_E_32_OFF);
privKey.getS(tmp, SCHNORR_D_32_OFF);
tmp[(short)(SCHNORR_TMP1_32_OFF - 1)] = (byte) crypto.addBig(tmp, SCHNORR_E_32_OFF, tmp, SCHNORR_D_32_OFF, tmp, SCHNORR_TMP1_32_OFF, SECP256K1_BYTE_SIZE);
multCipher.doFinal(tmp, SCHNORR_TMP1_OUT_OFF, SCHNORR_COMPONENT_SIZE, tmp, SCHNORR_TMP1_OUT_OFF);
tmp[(short)(SCHNORR_RES_32_OFF - 1)] = (byte) crypto.addBig(tmp, SCHNORR_E_32_OFF, tmp, SCHNORR_D_32_OFF, tmp, SCHNORR_RES_32_OFF, SECP256K1_BYTE_SIZE);
multCipher.doFinal(tmp, SCHNORR_RES_OUT_OFF, SCHNORR_COMPONENT_SIZE, tmp, SCHNORR_RES_OUT_OFF);
multCipher.doFinal(tmp, SCHNORR_D_OUT_OFF, SCHNORR_COMPONENT_SIZE, tmp, SCHNORR_D_OUT_OFF);
crypto.subBig(tmp, SCHNORR_TMP1_OUT_OFF, tmp, SCHNORR_D_OUT_OFF, tmp, SCHNORR_TMP1_OUT_OFF, SCHNORR_COMPONENT_SIZE);
crypto.subBig(tmp, SCHNORR_RES_OUT_OFF, tmp, SCHNORR_D_OUT_OFF, tmp, SCHNORR_RES_OUT_OFF, SCHNORR_COMPONENT_SIZE);
multCipher.doFinal(tmp, SCHNORR_E_OUT_OFF, SCHNORR_COMPONENT_SIZE, tmp, SCHNORR_E_OUT_OFF);
crypto.subBig(tmp, SCHNORR_TMP1_OUT_OFF, tmp, SCHNORR_E_OUT_OFF, tmp, SCHNORR_TMP1_OUT_OFF, SCHNORR_COMPONENT_SIZE);
crypto.subBig(tmp, SCHNORR_RES_OUT_OFF, tmp, SCHNORR_E_OUT_OFF, tmp, SCHNORR_RES_OUT_OFF, SCHNORR_COMPONENT_SIZE);
short res, res2;
divideResBy2();
for (short i = (short) (SCHNORR_COMPONENT_SIZE - 1); i >= 0; i--) {
res = (short) ((short) (tmp[(short)(SCHNORR_TMP1_OUT_OFF + i)] & 0xff) >> 1);
res2 = (short) ((short) (tmp[(short)(SCHNORR_TMP1_OUT_OFF + i - 1)] & 0xff) << 7);
tmp[(short)(SCHNORR_TMP1_OUT_OFF + i)] = (byte) ((short) (res | res2));
}
tmp[SCHNORR_TMP1_OUT_OFF] &= (byte) 0x7f;
crypto.addBig(tmp, SCHNORR_TMP1_OUT_OFF, SCHNORR_COMPONENT_SIZE, tmp, SCHNORR_K_OUT_OFF, SECP256K1_BYTE_SIZE, tmp, SCHNORR_TMP1_OUT_OFF);
Util.arrayCopyNonAtomic(tmp, SCHNORR_TMP1_64_OFF, output, (short) (outOff + Crypto.KEY_PUB_SIZE), SCHNORR_S_OUT_SIZE);
crypto.addBig(tmp, SCHNORR_RES_64_OFF, SCHNORR_S_OUT_SIZE, tmp, SCHNORR_K_OUT_OFF, SECP256K1_BYTE_SIZE, output, (short) (outOff + Crypto.KEY_PUB_SIZE));
return (short) (3 + Crypto.KEY_PUB_SIZE + SCHNORR_S_OUT_SIZE);
}
private void divideResBy2() {
short res, res2;
for (short i = (short) (SCHNORR_COMPONENT_SIZE - 1); i >= (short) (SCHNORR_COMPONENT_SIZE - SCHNORR_S_OUT_SIZE - 1); i--) {
res = (short) ((short) (tmp[(short)(SCHNORR_RES_OUT_OFF + i)] & 0xff) >> 1);
res2 = (short) ((short) (tmp[(short)(SCHNORR_RES_OUT_OFF + i - 1)] & 0xff) << 7);
tmp[(short)(SCHNORR_RES_OUT_OFF + i)] = (byte) ((short) (res | res2));
}
}
}