1 files changed, 12 insertions, 21 deletions
diff --git a/crypto/src/crypto/engines/RSACoreEngine.cs b/crypto/src/crypto/engines/RSACoreEngine.cs
index 2af447841..ffa448b3d 100644
--- a/crypto/src/crypto/engines/RSACoreEngine.cs
+++ b/crypto/src/crypto/engines/RSACoreEngine.cs
@@ -118,39 +118,30 @@ namespace Org.BouncyCastle.Crypto.Engines
{
CheckInitialised();
- if (key is RsaPrivateCrtKeyParameters)
+ if (key is RsaPrivateCrtKeyParameters crt)
{
//
// we have the extra factors, use the Chinese Remainder Theorem - the author
// wishes to express his thanks to Dirk Bonekaemper at rtsffm.com for
// advice regarding the expression of this.
//
- RsaPrivateCrtKeyParameters crtKey = (RsaPrivateCrtKeyParameters)key;
-
- BigInteger p = crtKey.P;
- BigInteger q = crtKey.Q;
- BigInteger dP = crtKey.DP;
- BigInteger dQ = crtKey.DQ;
- BigInteger qInv = crtKey.QInv;
-
- BigInteger mP, mQ, h, m;
+ BigInteger p = crt.P;
+ BigInteger q = crt.Q;
+ BigInteger dP = crt.DP;
+ BigInteger dQ = crt.DQ;
+ BigInteger qInv = crt.QInv;
// mP = ((input Mod p) ^ dP)) Mod p
- mP = (input.Remainder(p)).ModPow(dP, p);
+ BigInteger mP = (input.Remainder(p)).ModPow(dP, p);
- // mQ = ((input Mod q) ^ dQ)) Mod q
- mQ = (input.Remainder(q)).ModPow(dQ, q);
+ // mQ = ((input Mod q) ^ dQ)) Mod q
+ BigInteger mQ = (input.Remainder(q)).ModPow(dQ, q);
// h = qInv * (mP - mQ) Mod p
- h = mP.Subtract(mQ);
- h = h.Multiply(qInv);
- h = h.Mod(p); // Mod (in Java) returns the positive residual
-
- // m = h * q + mQ
- m = h.Multiply(q);
- m = m.Add(mQ);
+ BigInteger h = mP.Subtract(mQ).Multiply(qInv).Mod(p);
- return m;
+ // m = h * q + mQ
+ return h.Multiply(q).Add(mQ);
}
return input.ModPow(key.Exponent, key.Modulus);
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