diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/crypto/engines/RSACoreEngine.java')
| -rw-r--r-- | core/src/main/java/org/bouncycastle/crypto/engines/RSACoreEngine.java | 203 |
1 files changed, 0 insertions, 203 deletions
diff --git a/core/src/main/java/org/bouncycastle/crypto/engines/RSACoreEngine.java b/core/src/main/java/org/bouncycastle/crypto/engines/RSACoreEngine.java deleted file mode 100644 index 510cd5a5..00000000 --- a/core/src/main/java/org/bouncycastle/crypto/engines/RSACoreEngine.java +++ /dev/null @@ -1,203 +0,0 @@ -package org.bouncycastle.crypto.engines; - -import org.bouncycastle.crypto.CipherParameters; -import org.bouncycastle.crypto.DataLengthException; -import org.bouncycastle.crypto.params.ParametersWithRandom; -import org.bouncycastle.crypto.params.RSAKeyParameters; -import org.bouncycastle.crypto.params.RSAPrivateCrtKeyParameters; - -import java.math.BigInteger; - -/** - * this does your basic RSA algorithm. - */ -class RSACoreEngine -{ - private RSAKeyParameters key; - private boolean forEncryption; - - /** - * initialise the RSA engine. - * - * @param forEncryption true if we are encrypting, false otherwise. - * @param param the necessary RSA key parameters. - */ - public void init( - boolean forEncryption, - CipherParameters param) - { - if (param instanceof ParametersWithRandom) - { - ParametersWithRandom rParam = (ParametersWithRandom)param; - - key = (RSAKeyParameters)rParam.getParameters(); - } - else - { - key = (RSAKeyParameters)param; - } - - this.forEncryption = forEncryption; - } - - /** - * Return the maximum size for an input block to this engine. - * For RSA this is always one byte less than the key size on - * encryption, and the same length as the key size on decryption. - * - * @return maximum size for an input block. - */ - public int getInputBlockSize() - { - int bitSize = key.getModulus().bitLength(); - - if (forEncryption) - { - return (bitSize + 7) / 8 - 1; - } - else - { - return (bitSize + 7) / 8; - } - } - - /** - * Return the maximum size for an output block to this engine. - * For RSA this is always one byte less than the key size on - * decryption, and the same length as the key size on encryption. - * - * @return maximum size for an output block. - */ - public int getOutputBlockSize() - { - int bitSize = key.getModulus().bitLength(); - - if (forEncryption) - { - return (bitSize + 7) / 8; - } - else - { - return (bitSize + 7) / 8 - 1; - } - } - - public BigInteger convertInput( - byte[] in, - int inOff, - int inLen) - { - if (inLen > (getInputBlockSize() + 1)) - { - throw new DataLengthException("input too large for RSA cipher."); - } - else if (inLen == (getInputBlockSize() + 1) && !forEncryption) - { - throw new DataLengthException("input too large for RSA cipher."); - } - - byte[] block; - - if (inOff != 0 || inLen != in.length) - { - block = new byte[inLen]; - - System.arraycopy(in, inOff, block, 0, inLen); - } - else - { - block = in; - } - - BigInteger res = new BigInteger(1, block); - if (res.compareTo(key.getModulus()) >= 0) - { - throw new DataLengthException("input too large for RSA cipher."); - } - - return res; - } - - public byte[] convertOutput( - BigInteger result) - { - byte[] output = result.toByteArray(); - - if (forEncryption) - { - if (output[0] == 0 && output.length > getOutputBlockSize()) // have ended up with an extra zero byte, copy down. - { - byte[] tmp = new byte[output.length - 1]; - - System.arraycopy(output, 1, tmp, 0, tmp.length); - - return tmp; - } - - if (output.length < getOutputBlockSize()) // have ended up with less bytes than normal, lengthen - { - byte[] tmp = new byte[getOutputBlockSize()]; - - System.arraycopy(output, 0, tmp, tmp.length - output.length, output.length); - - return tmp; - } - } - else - { - if (output[0] == 0) // have ended up with an extra zero byte, copy down. - { - byte[] tmp = new byte[output.length - 1]; - - System.arraycopy(output, 1, tmp, 0, tmp.length); - - return tmp; - } - } - - return output; - } - - public BigInteger processBlock(BigInteger input) - { - if (key instanceof RSAPrivateCrtKeyParameters) - { - // - // 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.getP(); - BigInteger q = crtKey.getQ(); - BigInteger dP = crtKey.getDP(); - BigInteger dQ = crtKey.getDQ(); - BigInteger qInv = crtKey.getQInv(); - - BigInteger mP, mQ, h, m; - - // mP = ((input mod p) ^ dP)) mod p - mP = (input.remainder(p)).modPow(dP, p); - - // mQ = ((input mod q) ^ dQ)) mod q - 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); - - return m; - } - else - { - return input.modPow( - key.getExponent(), key.getModulus()); - } - } -} |