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32 lines
1.1 KiB
32 lines
1.1 KiB
2 years ago
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import BN from "../bn.js";
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import randomBytes from "../randombytes";
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function blind(priv) {
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var r = getr(priv);
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var blinder = r.toRed(BN.mont(priv.modulus)).redPow(new BN(priv.publicExponent)).fromRed();
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return { blinder: blinder, unblinder: r.invm(priv.modulus) };
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}
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function getr(priv) {
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var len = priv.modulus.byteLength();
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var r;
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do {
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r = new BN(randomBytes(len));
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} while (r.cmp(priv.modulus) >= 0 || !r.umod(priv.prime1) || !r.umod(priv.prime2));
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return r;
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}
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function crt(msg, priv) {
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var blinds = blind(priv);
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var len = priv.modulus.byteLength();
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var blinded = new BN(msg).mul(blinds.blinder).umod(priv.modulus);
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var c1 = blinded.toRed(BN.mont(priv.prime1));
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var c2 = blinded.toRed(BN.mont(priv.prime2));
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var qinv = priv.coefficient;
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var p = priv.prime1;
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var q = priv.prime2;
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var m1 = c1.redPow(priv.exponent1).fromRed();
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var m2 = c2.redPow(priv.exponent2).fromRed();
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var h = m1.isub(m2).imul(qinv).umod(p).imul(q);
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return m2.iadd(h).imul(blinds.unblinder).umod(priv.modulus).toArrayLike(Buffer, 'be', len);
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}
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crt.getr = getr;
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export default crt;
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