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PKCS12ParametersGenerator.javaAPI DocAndroid 1.5 API6089Wed May 06 22:41:06 BST 2009org.bouncycastle.crypto.generators

PKCS12ParametersGenerator

public class PKCS12ParametersGenerator extends org.bouncycastle.crypto.PBEParametersGenerator
Generator for PBE derived keys and ivs as defined by PKCS 12 V1.0.

The document this implementation is based on can be found at RSA's PKCS12 Page

Fields Summary
public static final int
KEY_MATERIAL
public static final int
IV_MATERIAL
public static final int
MAC_MATERIAL
private org.bouncycastle.crypto.Digest
digest
private int
u
private int
v
Constructors Summary
public PKCS12ParametersGenerator(org.bouncycastle.crypto.Digest digest)
Construct a PKCS 12 Parameters generator. This constructor will accept any digest which also implements ExtendedDigest.

param
digest the digest to be used as the source of derived keys.
exception
IllegalArgumentException if an unknown digest is passed in.


                                               
     
          
    
        this.digest = digest;
        if (digest instanceof ExtendedDigest)
        {
            u = digest.getDigestSize();
            v = ((ExtendedDigest)digest).getByteLength();
        }
        else
        {
            throw new IllegalArgumentException("Digest " + digest.getAlgorithmName() + " unsupported");
        }
Methods Summary
private voidadjust(byte[] a, int aOff, byte[] b)
add a + b + 1, returning the result in a. The a value is treated as a BigInteger of length (b.length * 8) bits. The result is modulo 2^b.length in case of overflow.

        int  x = (b[b.length - 1] & 0xff) + (a[aOff + b.length - 1] & 0xff) + 1;

        a[aOff + b.length - 1] = (byte)x;
        x >>>= 8;

        for (int i = b.length - 2; i >= 0; i--)
        {
            x += (b[i] & 0xff) + (a[aOff + i] & 0xff);
            a[aOff + i] = (byte)x;
            x >>>= 8;
        }
private byte[]generateDerivedKey(int idByte, int n)
generation of a derived key ala PKCS12 V1.0.

        byte[]  D = new byte[v];
        byte[]  dKey = new byte[n];

        for (int i = 0; i != D.length; i++)
        {
            D[i] = (byte)idByte;
        }

        byte[]  S;

        if ((salt != null) && (salt.length != 0))
        {
            S = new byte[v * ((salt.length + v - 1) / v)];

            for (int i = 0; i != S.length; i++)
            {
                S[i] = salt[i % salt.length];
            }
        }
        else
        {
            S = new byte[0];
        }

        byte[]  P;

        if ((password != null) && (password.length != 0))
        {
            P = new byte[v * ((password.length + v - 1) / v)];

            for (int i = 0; i != P.length; i++)
            {
                P[i] = password[i % password.length];
            }
        }
        else
        {
            P = new byte[0];
        }

        byte[]  I = new byte[S.length + P.length];

        System.arraycopy(S, 0, I, 0, S.length);
        System.arraycopy(P, 0, I, S.length, P.length);

        byte[]  B = new byte[v];
        int     c = (n + u - 1) / u;

        for (int i = 1; i <= c; i++)
        {
            byte[]  A = new byte[u];

            digest.update(D, 0, D.length);
            digest.update(I, 0, I.length);
            digest.doFinal(A, 0);
            for (int j = 1; j != iterationCount; j++)
            {
                digest.update(A, 0, A.length);
                digest.doFinal(A, 0);
            }

            for (int j = 0; j != B.length; j++)
            {
                B[j] = A[j % A.length];
            }

            for (int j = 0; j != I.length / v; j++)
            {
                adjust(I, j * v, B);
            }

            if (i == c)
            {
                System.arraycopy(A, 0, dKey, (i - 1) * u, dKey.length - ((i - 1) * u));
            }
            else
            {
                System.arraycopy(A, 0, dKey, (i - 1) * u, A.length);
            }
        }

        return dKey;
public org.bouncycastle.crypto.CipherParametersgenerateDerivedMacParameters(int keySize)
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.

        keySize = keySize / 8;

        byte[]  dKey = generateDerivedKey(MAC_MATERIAL, keySize);

        return new KeyParameter(dKey, 0, keySize);
public org.bouncycastle.crypto.CipherParametersgenerateDerivedParameters(int keySize)
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.

        keySize = keySize / 8;

        byte[]  dKey = generateDerivedKey(KEY_MATERIAL, keySize);

        return new KeyParameter(dKey, 0, keySize);
public org.bouncycastle.crypto.CipherParametersgenerateDerivedParameters(int keySize, int ivSize)
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.

        keySize = keySize / 8;
        ivSize = ivSize / 8;

        byte[]  dKey = generateDerivedKey(KEY_MATERIAL, keySize);

        byte[]  iv = generateDerivedKey(IV_MATERIAL, ivSize);

        return new ParametersWithIV(new KeyParameter(dKey, 0, keySize), iv, 0, ivSize);