非对称加密和对称加密混合应用

package com.cn.sec.rsa; import java.io.UnsupportedEncodingException; public class Base64 { /** * Chunk size per RFC 2045 section 6.8. * * <p>The {@value} character limit does not count the trailing CRLF, but counts * all other characters, including any equal signs.</p> * * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 6.8</a> */ static final int CHUNK_SIZE = 76; /** * Chunk separator per RFC 2045 section 2.1. * * @see <a href="http://www.ietf.org/rfc/rfc2045.txt">RFC 2045 section 2.1</a> */ static final byte[] CHUNK_SEPARATOR = "\r\n".getBytes(); /** * The base length. */ static final int BASELENGTH = 255; /** * Lookup length. */ static final int LOOKUPLENGTH = 64; /** * Used to calculate the number of bits in a byte. */ static final int EIGHTBIT = 8; /** * Used when encoding something which has fewer than 24 bits. */ static final int SIXTEENBIT = 16; /** * Used to determine how many bits data contains. */ static final int TWENTYFOURBITGROUP = 24; /** * Used to get the number of Quadruples. */ static final int FOURBYTE = 4; /** * Used to test the sign of a byte. */ static final int SIGN = -128; /** * Byte used to pad output. */ static final byte PAD = (byte) '='; // Create arrays to hold the base64 characters and a // lookup for base64 chars private static byte[] base64Alphabet = new byte[BASELENGTH]; private static byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH]; // Populating the lookup and character arrays static { for (int i = 0; i < BASELENGTH; i++) { base64Alphabet[i] = (byte) -1; } for (int i = 'Z'; i >= 'A'; i--) { base64Alphabet[i] = (byte) (i - 'A'); } for (int i = 'z'; i >= 'a'; i--) { base64Alphabet[i] = (byte) (i - 'a' + 26); } for (int i = '9'; i >= '0'; i--) { base64Alphabet[i] = (byte) (i - '0' + 52); } base64Alphabet['+'] = 62; base64Alphabet['/'] = 63; for (int i = 0; i <= 25; i++) { lookUpBase64Alphabet[i] = (byte) ('A' + i); } for (int i = 26, j = 0; i <= 51; i++, j++) { lookUpBase64Alphabet[i] = (byte) ('a' + j); } for (int i = 52, j = 0; i <= 61; i++, j++) { lookUpBase64Alphabet[i] = (byte) ('0' + j); } lookUpBase64Alphabet[62] = (byte) '+'; lookUpBase64Alphabet[63] = (byte) '/'; } private static boolean isBase64(byte octect) { if (octect == PAD) { return true; } else if (base64Alphabet[octect] == -1) { return false; } else { return true; } } /** * Tests a given byte array to see if it contains * only valid characters within the Base64 alphabet. * * @param arrayOctect byte array to test * @return true if all bytes are valid characters in the Base64 * alphabet or if the byte array is empty; false, otherwise */ public static boolean isArrayByteBase64(byte[] arrayOctect) { arrayOctect = discardWhitespace(arrayOctect); int length = arrayOctect.length; if (length == 0) { // shouldn't a 0 length array be valid base64 data? // return false; return true; } for (int i = 0; i < length; i++) { if (!isBase64(arrayOctect[i])) { return false; } } return true; } /** * Encodes binary data using the base64 algorithm but * does not chunk the output. * * @param binaryData binary data to encode * @return Base64 characters */ public static byte[] encodeBase64(byte[] binaryData) { return encodeBase64(binaryData, false); } /** * Encodes binary data using the base64 algorithm and chunks * the encoded output into 76 character blocks * * @param binaryData binary data to encode * @return Base64 characters chunked in 76 character blocks */ public static byte[] encodeBase64Chunked(byte[] binaryData) { return encodeBase64(binaryData, true); } /** * Decodes a byte[] containing containing * characters in the Base64 alphabet. * * @param pArray A byte array containing Base64 character data * @return a byte array containing binary data */ public static byte[] decode(byte[] pArray) { return decodeBase64(pArray); } /** * Encodes binary data using the base64 algorithm, optionally * chunking the output into 76 character blocks. * * @param binaryData Array containing binary data to encode. * @param isChunked if isChunked is true this encoder will chunk * the base64 output into 76 character blocks * @return Base64-encoded data. */ public static byte[] encodeBase64(byte[] binaryData, boolean isChunked) { int lengthDataBits = binaryData.length * EIGHTBIT; int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP; int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP; byte encodedData[] = null; int encodedDataLength = 0; int nbrChunks = 0; if (fewerThan24bits != 0) { //data not divisible by 24 bit encodedDataLength = (numberTriplets + 1) * 4; } else { // 16 or 8 bit encodedDataLength = numberTriplets * 4; } // If the output is to be "chunked" into 76 character sections, // for compliance with RFC 2045 MIME, then it is important to // allow for extra length to account for the separator(s) if (isChunked) { nbrChunks = (CHUNK_SEPARATOR.length == 0 ? 0 : (int) Math.ceil((float) encodedDataLength / CHUNK_SIZE)); encodedDataLength += nbrChunks * CHUNK_SEPARATOR.length; } encodedData = new byte[encodedDataLength]; byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0; int encodedIndex = 0; int dataIndex = 0; int i = 0; int nextSeparatorIndex = CHUNK_SIZE; int chunksSoFar = 0; //log.debug("number of triplets = " + numberTriplets); for (i = 0; i < numberTriplets; i++) { dataIndex = i * 3; b1 = binaryData[dataIndex]; b2 = binaryData[dataIndex + 1]; b3 = binaryData[dataIndex + 2]; //log.debug("b1= " + b1 +", b2= " + b2 + ", b3= " + b3); l = (byte) (b2 & 0x0f); k = (byte) (b1 & 0x03); byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0); byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0); byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc); encodedData[encodedIndex] = lookUpBase64Alphabet[val1]; //log.debug( "val2 = " + val2 ); //log.debug( "k4 = " + (k<<4) ); //log.debug( "vak = " + (val2 | (k<<4)) ); encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)]; encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3]; encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f]; encodedIndex += 4; // If we are chunking, let's put a chunk separator down. if (isChunke