一个简单的RSA算法实现JAVA源代码

filename:RSA.java /* * Created on Mar 3, 2005 * * TODO To change the template for this generated file go to * Window - Preferences - Java - Code Style - Code Templates */ import java.math.BigInteger; import java.io.InputStream; import java.io.OutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.FileWriter; import java.io.FileReader; import java.io.BufferedReader; import java.util.StringTokenizer; /** * @author Steve * * TODO To change the template for this generated type comment go to * Window - Preferences - Java - Code Style - Code Templates */ public class RSA { /** * BigInteger.ZERO */ private static final BigInteger ZERO = BigInteger.ZERO; /** * BigInteger.ONE */ private static final BigInteger ONE = BigInteger.ONE; /** * Pseudo BigInteger.TWO */ private static final BigInteger TWO = new BigInteger("2"); private BigInteger myKey; private BigInteger myMod; private int blockSize; public RSA (BigInteger key, BigInteger n, int b) { myKey = key; myMod = n; blockSize = b; } public void encodeFile (String filename) { byte[] bytes = new byte[blockSize / 8 + 1]; byte[] temp; int tempLen; InputStream is = null; FileWriter writer = null; try { is = new FileInputStream(filename); writer = new FileWriter(filename + ".enc"); } catch (FileNotFoundException e1){ System.out.println("File not found: " + filename); } catch (IOException e1){ System.out.println("File not found: " + filename + ".enc"); } /** * Write encoded message to 'filename'.enc */ try { while ((tempLen = is.read(bytes, 1, blockSize / 8)) > 0) { for (int i = tempLen + 1; i < bytes.length; ++i) { bytes[i] = 0; } writer.write(encodeDecode(new BigInteger(bytes)) + " "); } } catch (IOException e1) { System.out.println("error writing to file"); } /** * Close input stream and file writer */ try { is.close(); writer.close(); } catch (IOException e1) { System.out.println("Error closing file."); } } public void decodeFile (String filename) { FileReader reader = null; OutputStream os = null; try { reader = new FileReader(filename); os = new FileOutputStream(filename.replaceAll(".enc", ".dec")); } catch (FileNotFoundException e1) { if (reader == null) System.out.println("File not found: " + filename); else System.out.println("File not found: " + filename.replaceAll(".enc", "dec")); } BufferedReader br = new BufferedReader(reader); int offset; byte[] temp, toFile; StringTokenizer st = null; try { while (br.ready()) { st = new StringTokenizer(br.readLine()); while (st.hasMoreTokens()){ toFile = encodeDecode(new BigInteger(st.nextToken())).toByteArray(); System.out.println(toFile.length + " x " + (blockSize / 8)); if (toFile[0] == 0 && toFile.length != (blockSize / 8)) { temp = new byte[blockSize / 8]; offset = temp.length - toFile.length; for (int i = toFile.length - 1; (i <= 0) && ((i + offset) <= 0); --i) { temp[i + offset] = toFile[i]; } toFile = temp; } /*if (toFile.length != ((blockSize / 8) + 1)){ temp = new byte[(blockSize / 8) + 1]; System.out.println(toFile.length + " x " + temp.length); for (int i = 1; i < temp.length; i++) { temp[i] = toFile[i - 1]; } toFile = temp; } else System.out.println(toFile.length + " " + ((blockSize / 8) + 1));*/ os.write(toFile); } } } catch (IOException e1) { System.out.println("Something went wrong"); } /** * close data streams */ try { os.close(); reader.close(); } catch (IOException e1) { System.out.println("Error closing file."); } } /** * Performs <tt>base</tt>^<sup><tt>pow</tt></sup> within the modular * domain of <tt>mod</tt>. * * @param base the base to be raised * @param pow the power to which the base will be raisded * @param mod the modular domain over which to perform this operation * @return <tt>base</tt>^<sup><tt>pow</tt></sup> within the modular * domain of <tt>mod</tt>. */ public BigInteger encodeDecode(BigInteger base) { BigInteger a = ONE; BigInteger s = base; BigInteger n = myKey; while (!n.equals(ZERO)) { if(!n.mod(TWO).equals(ZERO)) a = a.multiply(s).mod(myMod); s = s.pow(2).mod(myMod); n = n.divide(TWO); } return a; } } 在这里提供两个版本的RSA算法JAVA实现的代码下载： 1. 来自于 http://www.javafr.com/code.aspx?ID=27020的RSA算法实现源代码包: http://zeal.newmenbase.net/attachment/JavaFR_RSA_Source.rar 2. 来自于 http://www.ferrara.linux.it/Members/lucabariani/RSA/implementazioneRsa/的实现: http://zeal.newmenbase.net/attachment/sorgentiJava.tar.gz - 源代码包 http://zeal.newmenbase.net/attachment/algoritmoRSA.jar- 编译好的jar包 另外关于RSA算法的php实现请参见文章: php下的RSA算法实现 关于使用VB实现RSA算法的源代码下载(此程序采用了psc1算法来实现快速的RSA加密): http://zeal.newmenbase.net/attachment/vb_PSC1_RSA.rar RSA加密的JavaScript实现: http://www.ohdave.com/rsa/