diff options
author | David Hook <dgh@cryptoworkshop.com> | 2013-05-31 11:07:45 +0400 |
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committer | David Hook <dgh@cryptoworkshop.com> | 2013-05-31 11:07:45 +0400 |
commit | 2b976f5364cfdbc37d3086019d93483c983eb80b (patch) | |
tree | cb846af3fd1d43f9c2562a1fb2d06b997ad8f229 /core/src/main/java/org/bouncycastle/crypto/generators/PKCS5S2ParametersGenerator.java | |
parent | 5f714bd92fbd780d22406f4bc3681be005f6f04a (diff) |
initial reshuffle
Diffstat (limited to 'core/src/main/java/org/bouncycastle/crypto/generators/PKCS5S2ParametersGenerator.java')
-rw-r--r-- | core/src/main/java/org/bouncycastle/crypto/generators/PKCS5S2ParametersGenerator.java | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/core/src/main/java/org/bouncycastle/crypto/generators/PKCS5S2ParametersGenerator.java b/core/src/main/java/org/bouncycastle/crypto/generators/PKCS5S2ParametersGenerator.java new file mode 100644 index 00000000..640ead46 --- /dev/null +++ b/core/src/main/java/org/bouncycastle/crypto/generators/PKCS5S2ParametersGenerator.java @@ -0,0 +1,153 @@ +package org.bouncycastle.crypto.generators; + +import org.bouncycastle.crypto.CipherParameters; +import org.bouncycastle.crypto.Digest; +import org.bouncycastle.crypto.Mac; +import org.bouncycastle.crypto.PBEParametersGenerator; +import org.bouncycastle.crypto.digests.SHA1Digest; +import org.bouncycastle.crypto.macs.HMac; +import org.bouncycastle.crypto.params.KeyParameter; +import org.bouncycastle.crypto.params.ParametersWithIV; + +/** + * Generator for PBE derived keys and ivs as defined by PKCS 5 V2.0 Scheme 2. + * This generator uses a SHA-1 HMac as the calculation function. + * <p> + * The document this implementation is based on can be found at + * <a href=http://www.rsasecurity.com/rsalabs/pkcs/pkcs-5/index.html> + * RSA's PKCS5 Page</a> + */ +public class PKCS5S2ParametersGenerator + extends PBEParametersGenerator +{ + private Mac hMac; + private byte[] state; + + /** + * construct a PKCS5 Scheme 2 Parameters generator. + */ + public PKCS5S2ParametersGenerator() + { + this(new SHA1Digest()); + } + + public PKCS5S2ParametersGenerator(Digest digest) + { + hMac = new HMac(digest); + state = new byte[hMac.getMacSize()]; + } + + private void F( + byte[] S, + int c, + byte[] iBuf, + byte[] out, + int outOff) + { + if (c == 0) + { + throw new IllegalArgumentException("iteration count must be at least 1."); + } + + if (S != null) + { + hMac.update(S, 0, S.length); + } + + hMac.update(iBuf, 0, iBuf.length); + hMac.doFinal(state, 0); + + System.arraycopy(state, 0, out, outOff, state.length); + + for (int count = 1; count < c; count++) + { + hMac.update(state, 0, state.length); + hMac.doFinal(state, 0); + + for (int j = 0; j != state.length; j++) + { + out[outOff + j] ^= state[j]; + } + } + } + + private byte[] generateDerivedKey( + int dkLen) + { + int hLen = hMac.getMacSize(); + int l = (dkLen + hLen - 1) / hLen; + byte[] iBuf = new byte[4]; + byte[] outBytes = new byte[l * hLen]; + int outPos = 0; + + CipherParameters param = new KeyParameter(password); + + hMac.init(param); + + for (int i = 1; i <= l; i++) + { + // Increment the value in 'iBuf' + int pos = 3; + while (++iBuf[pos] == 0) + { + --pos; + } + + F(salt, iterationCount, iBuf, outBytes, outPos); + outPos += hLen; + } + + return outBytes; + } + + /** + * Generate a key parameter derived from the password, salt, and iteration + * count we are currently initialised with. + * + * @param keySize the size of the key we want (in bits) + * @return a KeyParameter object. + */ + public CipherParameters generateDerivedParameters( + int keySize) + { + keySize = keySize / 8; + + byte[] dKey = generateDerivedKey(keySize); + + return new KeyParameter(dKey, 0, keySize); + } + + /** + * Generate a key with initialisation vector parameter derived from + * the password, salt, and iteration count we are currently initialised + * with. + * + * @param keySize the size of the key we want (in bits) + * @param ivSize the size of the iv we want (in bits) + * @return a ParametersWithIV object. + */ + public CipherParameters generateDerivedParameters( + int keySize, + int ivSize) + { + keySize = keySize / 8; + ivSize = ivSize / 8; + + byte[] dKey = generateDerivedKey(keySize + ivSize); + + return new ParametersWithIV(new KeyParameter(dKey, 0, keySize), dKey, keySize, ivSize); + } + + /** + * Generate a key parameter for use with a MAC derived from the password, + * salt, and iteration count we are currently initialised with. + * + * @param keySize the size of the key we want (in bits) + * @return a KeyParameter object. + */ + public CipherParameters generateDerivedMacParameters( + int keySize) + { + return generateDerivedParameters(keySize); + } +} |