bigintegers.java

J2ME加密算法的代码!里面包括常用的算法

package org.bouncycastle.util;

import java.math.BigInteger;

/**
 * BigInteger utilities.
 */
public final class BigIntegers
{
    /**
     * Return the passed in value as an unsigned byte array.
     * 
     * @param value value to be converted.
     * @return a byte array without a leading zero byte if present in the signed encoding.
     */
    public static byte[] asUnsignedByteArray(
        BigInteger value)
    {
        byte[] bytes = value.toByteArray();
        
        if (bytes[0] == 0)
        {
            byte[] tmp = new byte[bytes.length - 1];
            
            System.arraycopy(bytes, 1, tmp, 0, tmp.length);
            
            return tmp;
        }
        
        return bytes;
    }
}