[Android/안드로이드] Android 와 JSP 간 파라미터 암복호화 (2)

2. JSP 테스트 페이지 만들기

Android WebView에서 우리가 만든 JSP 파일을 로드해서 사용할텐데 

로드된 페이지에서 전송할 파라미터 암호화를 안한다면 컨텐츠의 노출 위험이 있다.

그래서 암복호화 클래스를 만들어서 서버와 안드로이드에 로드하는 과정을 추가한다. 

( Web에서 파라미터 암호화 -> Android에서 파라미터 복호화)

암복호화 클래스

 

package com.test.decodeparam;
import java.util.Date;
 
public class Decrypt {
    public static void main(String[] args) {
        Decrypt dec = new Decrypt();
        // TODO Auto-generated method stub
        String Text = "TEST";
        System.out.println(Text);
        String strEncText = dec.AESEncrypt(Text, "Key");
        System.out.println(strEncText);
        String strDecText = dec.AESDecrypt(strEncText, "Key");
        System.out.println(strDecText);
    }
 
    String g_strBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
 
    byte g_byArrSbox[] = {0x63,0x7c,0x77,0x7b,-14,0x6b,0x6f,-59,0x30,0x01,0x67,0x2b,-2,-41,-85,0x76,
                          -54,-126,-55,0x7d,-6,0x59,0x47,-16,-83,-44,-94,-81,-100,-92,0x72,-64,
                          -73,-3,-109,0x26,0x36,0x3f,-9,-52,0x34,-91,-27,-15,0x71,-40,0x31,0x15,
                          0x04,-57,0x23,-61,0x18,-106,0x05,-102,0x07,0x12,-128,-30,-21,0x27,-78,0x75,
                          0x09,-125,0x2c,0x1a,0x1b,0x6e,0x5a,-96,0x52,0x3b,-42,-77,0x29,-29,0x2f,-124,
                          0x53,-47,0x00,-19,0x20,-4,-79,0x5b,0x6a,-53,-66,0x39,0x4a,0x4c,0x58,-49,
                          -48,-17,-86,-5,0x43,0x4d,0x33,-123,0x45,-7,0x02,0x7f,0x50,0x3c,-97,-88,
                          0x51,-93,0x40,-113,-110,-99,0x38,-11,-68,-74,-38,0x21,0x10,-1,-13,-46,
                          -51,0x0c,0x13,-20,0x5f,-105,0x44,0x17,-60,-89,0x7e,0x3d,0x64,0x5d,0x19,0x73,
                          0x60,-127,0x4f,-36,0x22,0x2a,-112,-120,0x46,-18,-72,0x14,-34,0x5e,0x0b,-37,
                          -32,0x32,0x3a,0x0a,0x49,0x06,0x24,0x5c,-62,-45,-84,0x62,-111,-107,-28,0x79,
                          -25,-56,0x37,0x6d,-115,-43,0x4e,-87,0x6c,0x56,-12,-22,0x65,0x7a,-82,0x08,
                          -70,0x78,0x25,0x2e,0x1c,-90,-76,-58,-24,-35,0x74,0x1f,0x4b,-67,-117,-118,
                          0x70,0x3e,-75,0x66,0x48,0x03,-10,0x0e,0x61,0x35,0x57,-71,-122,-63,0x1d,-98,
                          -31,-8,-104,0x11,0x69,-39,-114,-108,-101,0x1e,-121,-23,-50,0x55,0x28,-33,
                          -116,-95,-119,0x0d,-65,-26,0x42,0x68,0x41,-103,0x2d,0x0f,-80,0x54,-69,0x16};
 
    byte g_byArrRcon[][] = {{0x00, 0x00, 0x00, 0x00},
                            {0x01, 0x00, 0x00, 0x00},
                            {0x02, 0x00, 0x00, 0x00},
                            {0x04, 0x00, 0x00, 0x00},
                            {0x08, 0x00, 0x00, 0x00},
                            {0x10, 0x00, 0x00, 0x00},
                            {0x20, 0x00, 0x00, 0x00},
                            {0x40, 0x00, 0x00, 0x00},
                            {-128, 0x00, 0x00, 0x00},
                            {0x1b, 0x00, 0x00, 0x00},
                            {0x36, 0x00, 0x00, 0x00}};
 
    public byte[] RotWord(byte[] byArrInput)
    {
        byte byArrRet[] = new byte[4];
        byArrRet[0] = byArrInput[1];
        byArrRet[1] = byArrInput[2];
        byArrRet[2] = byArrInput[3];
        byArrRet[3] = byArrInput[0];
 
        return byArrRet;
    }
 
    public void SubWord(byte[] byArr)
    {
        for (int nLoop = 0; nLoop < 4; nLoop++)
        {
            if (byArr[nLoop] < 0)
                byArr[nLoop] = g_byArrSbox[byArr[nLoop] + 256];
            else
                byArr[nLoop] = g_byArrSbox[byArr[nLoop]];
        }
    }
 
    public ByteArrayRet KeyExpansion(ByteArrayRet barInput)
    {
        ByteArrayRet ret = new ByteArrayRet();
        ret.nLength = 176;
 
        int nBlockSie = 4;
        int nKeyLength = 4;
        int nRound = 10;
        int nLoop;
        int nLoop2;
 
        // 앞 16 바이트 베끼기
        for (nLoop = 0; nLoop < 16; nLoop++)
            ret.byArray[nLoop] = barInput.byArray[nLoop];
 
        byte byArrTemp[] = new byte[4];
        byte byArrTemp2[] = new byte[4];
        for (nLoop = nKeyLength; nLoop < 44; nLoop++)
        {
            for (nLoop2 = 0; nLoop2 < 4; nLoop2++)
                byArrTemp[nLoop2] = ret.byArray[(nLoop - 1) * 4 + nLoop2];
 
            if ((nLoop % nKeyLength) == 0)
            {
                byArrTemp2 = RotWord(byArrTemp);
                SubWord(byArrTemp2);
 
                for (nLoop2 = 0; nLoop2 < 4; nLoop2++)
                {
                    Integer nConvert = byArrTemp2[nLoop2] ^ g_byArrRcon[nLoop / nKeyLength][nLoop2];
                    byArrTemp[nLoop2] = nConvert.byteValue();
                }
            }
 
            for (nLoop2 = 0; nLoop2 < 4; nLoop2++)
            {
                Integer nConvert = ret.byArray[(nLoop - nKeyLength) * 4 + nLoop2] ^ byArrTemp[nLoop2];
                ret.byArray[nLoop * 4 + nLoop2] = nConvert.byteValue();
            }
        }
 
        return ret;
    }
 
    public ByteArrayRet EncodeUTF8(String strInput)
    {
        ByteArrayRet ret = new ByteArrayRet();
 
        int nOneChar;
        for (int nLoop = 0; nLoop < strInput.length(); nLoop++)
        {
            nOneChar = (int)strInput.charAt(nLoop);
 
            if (nOneChar < 0x80)
                ret.byArray[ret.nLength++] = (byte)nOneChar;
            else if (nOneChar < 0x800)
            {
                ret.byArray[ret.nLength++] = (byte)(0xc0 | nOneChar >> 6);
                ret.byArray[ret.nLength++] = (byte)(0x80 | nOneChar & 0x3f);
            }
            else
            {
                ret.byArray[ret.nLength++] = (byte)(0xe0 | nOneChar >> 12);
                ret.byArray[ret.nLength++] = (byte)(0x80 | nOneChar >> 6 & 0x3f);
                ret.byArray[ret.nLength++] = (byte)(0x80 | nOneChar & 0x3f);
            }
        }
 
        return ret;
    }
 
    public ByteArrayRet DecodeUTF8(ByteArrayRet barArg)
    {
        ByteArrayRet ret = new ByteArrayRet();
        int nDivide;
        for (int nLoop = 0; nLoop < barArg.nLength; nLoop++)
        {
            //if (barArg.byArray[nLoop] < 0x80)
            if (barArg.byArray[nLoop] >= 0)
            {
                ret.byArray[ret.nLength++] = barArg.byArray[nLoop];
                ret.byArray[ret.nLength++] = 0;
            }
            else
            {
                //if ((0xc0 <= barArg.byArray[nLoop]) && (barArg.byArray[nLoop] <= 0xdf) && (0x80 <= barArg.byArray[nLoop + 1]) && (barArg.byArray[nLoop + 1] <= 0xbf))
                if ((-64 <= barArg.byArray[nLoop]) && (barArg.byArray[nLoop] <= -33) && (0 > barArg.byArray[nLoop + 1]) && (barArg.byArray[nLoop + 1] >= -65))
                {
                    nDivide = ((barArg.byArray[nLoop++] & 0x1f) << 6) | (barArg.byArray[nLoop] & 0x3f);
                    ret.byArray[ret.nLength++] = (byte)nDivide;
                    nDivide = nDivide >> 8;
                    ret.byArray[ret.nLength++] = (byte)nDivide;
                }
                else
                {
                    //if ((0xe0 <= barArg.byArray[nLoop]) && (barArg.byArray[nLoop] <= 0xef) && (0x80 <= barArg.byArray[nLoop + 1]) && (barArg.byArray[nLoop + 1] <= 0xbf) && (0x80 <= barArg.byArray[nLoop + 2]) && (barArg.byArray[nLoop + 2] <= 0xbf))
                    if ((-32 <= barArg.byArray[nLoop]) && (barArg.byArray[nLoop] <= -17) && (-65 >= barArg.byArray[nLoop + 1]) && (-65 >= barArg.byArray[nLoop + 2]))
                    {
                        nDivide = ((barArg.byArray[nLoop++] & 0xf) << 12) | ((barArg.byArray[nLoop++] & 0x3f) << 6) | (barArg.byArray[nLoop] & 0x3f);
                        ret.byArray[ret.nLength++] = (byte)nDivide;
                        nDivide = nDivide >> 8;
                        ret.byArray[ret.nLength++] = (byte)nDivide;
                    }
                }
            }
 
            // 이거 넣으면 어떨까?
            if ((ret.byArray[ret.nLength - 2] == 0) && ((ret.nLength % 2) == 0))
                return ret;
        }
 
        return ret;
    }
 
    public class ByteArrayRet
    {
        byte byArray[];
        int nLength;
 
        public ByteArrayRet()
        {
            byArray = new byte[1024];
            nLength = 0;
        }
 
        public String toString2()
        {
            String strRetVal = "";
            String strTemp;
 
            //strRetVal = this.byArray.toString();
 
            for (int nTemp = 0; nTemp < nLength; nTemp++)
            {
                if ((nTemp % 8) == 0)
                    strRetVal += "<br>";
 
                strTemp = Integer.toHexString(byArray[nTemp]);
                if (strTemp.length() > 2)
                    strRetVal += strTemp.substring(6) + ", ";
                else if (strTemp.length() == 1)
                    strRetVal += "0" + strTemp + ", ";
                else
                    strRetVal += strTemp + ", ";
            }
 
            return strRetVal;
        }
    }
 
    public void AddRoundKey(ByteArrayRet barArg, ByteArrayRet barKey, int nRound, int nArg)
    {
        for (int i = 0; i < 4; i++)
            for (int j = 0; j < nArg; j++){
                barArg.byArray[i * 4 + j] ^= barKey.byArray[(nRound * 4 + j) * 4 + i];
            }
    }
 
    public void SubBytes(ByteArrayRet barArg, int nArg)
    {
        for (int i = 0; i < 4; i++)
            for (int j = 0; j < nArg; j++){
                if (barArg.byArray[i * 4 + j] < 0)
                    barArg.byArray[i * 4 + j] = g_byArrSbox[barArg.byArray[i * 4 + j] + 256];
                else
                    barArg.byArray[i * 4 + j] = g_byArrSbox[barArg.byArray[i * 4 + j]];
            }
    }
 
    public void ShiftRows(ByteArrayRet barArg, int nArg)
    {
        byte byTemp[] = new byte[4];
        for (int i = 1; i < 4; i++)
        {
            for (int j = 0; j < 4; j++)
                byTemp[j] = barArg.byArray[i * 4 + (i + j) % nArg];
 
            for (int j = 0; j < 4; j++)
                barArg.byArray[i * 4 + j] = byTemp[j];
        }
    }
 
    public void MixColumns(ByteArrayRet barArg)
    {
        byte byTemp1[] = new byte[4];
        byte byTemp2[] = new byte[4];
        Integer nTemp;
 
        for (int i = 0; i < 4; i++)
        {
            for (int j = 0; j < 4; j++)
            {
                byTemp1[j] = barArg.byArray[j * 4 + i];
                nTemp = (( barArg.byArray[j * 4 + i] & 0x80) != 0) ? barArg.byArray[j * 4 + i] << 1 ^ 0x11b : barArg.byArray[j * 4 + i] << 1;
                byTemp2[j] = nTemp.byteValue();
            }
 
            nTemp = byTemp2[0] ^ byTemp1[1] ^ byTemp2[1] ^ byTemp1[2] ^ byTemp1[3];
            barArg.byArray[0 * 4 + i] = nTemp.byteValue();
            nTemp = byTemp1[0] ^ byTemp2[1] ^ byTemp1[2] ^ byTemp2[2] ^ byTemp1[3];
            barArg.byArray[1 * 4 + i] = nTemp.byteValue();
            nTemp = byTemp1[0] ^ byTemp1[1] ^ byTemp2[2] ^ byTemp1[3] ^ byTemp2[3];
            barArg.byArray[2 * 4 + i] = nTemp.byteValue();
            nTemp = byTemp1[0] ^ byTemp2[0] ^ byTemp1[1] ^ byTemp1[2] ^ byTemp2[3];
            barArg.byArray[3 * 4 + i] = nTemp.byteValue();
        }
    }
    
    String EncodeBase64(ByteArrayRet barArg, int nLength)
    {
        String strRet = new String();
        
        byte ch1, ch2, ch3;
        byte nEnc1, nEnc2, nEnc3, nEnc4;
        int nLoop = 0;
        
        do
        {
            ch1 = barArg.byArray[nLoop++];
            ch2 = (nLoop++ < nLength) ? barArg.byArray[nLoop - 1] : 0;
            ch3 = (nLoop++ < nLength) ? barArg.byArray[nLoop - 1] : 0;
            
            nEnc1 = (byte)((ch1 >> 2) & 0x3f);
            nEnc2 = (byte)(((ch1 & 3) << 4) | ((ch2 >> 4) & 0x0f));
            nEnc3 = (byte)(((ch2 & 15) << 2) | ((ch3 >> 6) & 0x03));
            nEnc4 = (byte)(ch3 & 63);
            
            switch (nLoop - nLength)
            {
            case 1:
                nEnc4 = (byte)64;
                break;
                
            case 2:
                nEnc3 = nEnc4 = (byte)64;
                break;
            }
            
            Character ch = new Character(g_strBase64.charAt(nEnc1));
            strRet += ch.toString();
            ch = new Character(g_strBase64.charAt(nEnc2));
            strRet += ch.toString();
            ch = new Character(g_strBase64.charAt(nEnc3));
            strRet += ch.toString();
            ch = new Character(g_strBase64.charAt(nEnc4));
            strRet += ch.toString();
        }
        while (nLoop < nLength);
        
        return strRet;
    }
    
    public ByteArrayRet DecodeBase64(String strCipherText)
    {
        ByteArrayRet ret = new ByteArrayRet();
        ret.nLength = 0;
 
        int nEnc1, nEnc2, nEnc3, nEnc4;
        int ch1, ch2, ch3;
        int nLoop = 0;
 
        do
        {
            nEnc1 = g_strBase64.indexOf(strCipherText.charAt(nLoop++));
            nEnc2 = g_strBase64.indexOf(strCipherText.charAt(nLoop++));
            nEnc3 = g_strBase64.indexOf(strCipherText.charAt(nLoop++));
            nEnc4 = g_strBase64.indexOf(strCipherText.charAt(nLoop++));
 
            ch1 = (nEnc1 << 2) | (nEnc2 >> 4);
            ch2 = ((nEnc2 & 15) << 4 ) | (nEnc3 >> 2);
            ch3 = ((nEnc3 & 3) << 6) | nEnc4;
 
            ret.byArray[ret.nLength++] = (byte)ch1;
            if (nEnc3 != 64)
                ret.byArray[ret.nLength++] = (byte)ch2;
            if (nEnc4 != 64)
                ret.byArray[ret.nLength++] = (byte)ch3;
        }
        while (nLoop < strCipherText.length());
 
        return ret;
    }
 
    public ByteArrayRet Cipher(ByteArrayRet barKey, ByteArrayRet barKE)
    {
        ByteArrayRet ret = new ByteArrayRet(); 
        ret.nLength = 16;
 
        int nBlockSize = 4;
        int nRound = 10;
        int nLoop = 0;
 
        ByteArrayRet barState = new ByteArrayRet();
        barState.nLength = 16;
        for (nLoop = 0; nLoop < 16; nLoop++)
            barState.byArray[(nLoop % 4) * 4 + (int)Math.floor(nLoop / 4)] = barKey.byArray[nLoop];
        
        
        AddRoundKey(barState, barKE, 0, nBlockSize);
 
        for (nLoop = 1; nLoop < nRound; nLoop++)
        {
            SubBytes(barState, nBlockSize);
            ShiftRows(barState, nBlockSize);
            MixColumns(barState);
            AddRoundKey(barState, barKE, nLoop, nBlockSize);
        }
 
        SubBytes(barState, nBlockSize);
        ShiftRows(barState, nBlockSize);
        AddRoundKey(barState, barKE, nRound, nBlockSize);
 
        for (nLoop = 0; nLoop < 4 * nBlockSize; nLoop++)
            ret.byArray[nLoop] = barState.byArray[(nLoop % 4) * 4 + (int)Math.floor(nLoop / 4)];
        
        return ret;
    }
 
    public String AESEncrypt(String strPlainText, String strPassword)
    {
        // strPlainText를 UTF8로
        ByteArrayRet barUTF8Text = EncodeUTF8(strPlainText);
 
        // strPassword를 UTF8로
        ByteArrayRet barUTF8PW = EncodeUTF8(strPassword);
 
        // use AES itself to encrypt password to get cipher key (using plain password as source for key expansion) - gives us well encrypted key
        ByteArrayRet barKey = new ByteArrayRet();
        barKey.nLength = 16;
        barKey.byArray = new byte[16];
        int nLoop;
        for (nLoop = 0; nLoop < 16; nLoop++){
            barKey.byArray[nLoop] = /*isNaN(barUTF8PW.byArray[nLoop]) ? 0 : */barUTF8PW.byArray[nLoop];
        }
        
        // 키 만들기
        ByteArrayRet barKE = KeyExpansion(barKey);
 
        // 암호화
        ByteArrayRet barCipher = Cipher(barKey, barKE);
        
        // 시간 알아오기
        Date dNow = new Date();
        long lCurrentTime = dNow.getTime();
        long lTime = lCurrentTime / 1000;
        byte bySec = (byte)(lTime & 0xFF);
        
        /*
        /////////////////////////////////////////////////////////
        lTime = 1239583474;
        bySec = 34;
        /////////////////////////////////////////////////////////
        */
 
        // initialise counter block (NIST SP800-38A §B.2): millisecond time-stamp for nonce in 1st 8 bytes, block counter in 2nd 8 bytes
        ByteArrayRet barCounterBlock = new ByteArrayRet();
        barCounterBlock.nLength = 16;
        barCounterBlock.byArray = new byte[16];
        
        // encode nonce with seconds in 1st 4 bytes, and (repeated) ms part filling 2nd 4 bytes
        for (nLoop = 0; nLoop < 4; nLoop++)
        {
            barCounterBlock.byArray[nLoop] = (byte)((lTime >> nLoop * 8) & 0xFF);
            barCounterBlock.byArray[nLoop + 4] = (byte)(bySec & 0xFF);
        }
        
        // and convert it to a string to go on the front of the ciphertext
        int nBlockCount = (int)Math.ceil((double)barUTF8Text.nLength / 16);
        
        ByteArrayRet barCipherText = new ByteArrayRet();
        barCipherText.nLength = nBlockCount * 16 + 8;
        barCipherText.byArray = new byte[barCipherText.nLength];
        barCipherText.byArray[0] = barCounterBlock.byArray[0];
        barCipherText.byArray[1] = barCounterBlock.byArray[1];
        barCipherText.byArray[2] = barCounterBlock.byArray[2];
        barCipherText.byArray[3] = barCounterBlock.byArray[3];
        barCipherText.byArray[4] = barCounterBlock.byArray[4];
        barCipherText.byArray[5] = barCounterBlock.byArray[5];
        barCipherText.byArray[6] = barCounterBlock.byArray[6];
        barCipherText.byArray[7] = barCounterBlock.byArray[7];
        
        // generate key schedule - an expansion of the key into distinct Key Rounds for each round
        ByteArrayRet barKeySchedule = KeyExpansion(barCipher);
        
        int nBlockSize = 16;
        int nBlockLength = 0;
        int nLoop2 = 0;
        ByteArrayRet barCipherCntr = new ByteArrayRet();
        
        for (nLoop = 0; nLoop < nBlockCount; nLoop++)
        {
            barCounterBlock.byArray[15] = (byte)nLoop;
            
            barCipherCntr = Cipher(barCounterBlock, barKeySchedule);
            
            nBlockLength = (nLoop < nBlockCount - 1) ? nBlockSize : (barUTF8Text.nLength - 1) % nBlockSize + 1;
            for (nLoop2 = 0; nLoop2 < nBlockLength; nLoop2++)
                barCipherText.byArray[nLoop * 16 + nLoop2 + 8] = (byte)(barCipherCntr.byArray[nLoop2] ^ barUTF8Text.byArray[nLoop * nBlockSize + nLoop2]);
            
        }
        
        return EncodeBase64(barCipherText, (nLoop - 1) * 16 + nLoop2 + 8);
        
        //return strRet;
    }
 
    public String AESDecrypt(String strCipherText, String strPassword)
    {
        // strCipherText를 Base64 풀기
        ByteArrayRet barBase64Dec = DecodeBase64(strCipherText);
        
        // strPassword를 UTF8로
        ByteArrayRet barUTF8PW = EncodeUTF8(strPassword);
        
 
        // use AES to encrypt password (mirroring encrypt routine)
        ByteArrayRet barKey = new ByteArrayRet();// byArray
        barKey.nLength = 16;
        barKey.byArray = new byte[16];
        for (int nLoop = 0; nLoop < 16; nLoop++)
            barKey.byArray[nLoop] = barUTF8PW.byArray[nLoop];
        
        // 키 만들기
        ByteArrayRet barKE = KeyExpansion(barKey);// byKey
 
        // 암호화
        ByteArrayRet barCipher = Cipher(barKey, barKE);// byCipher
 
        // recover nonce from 1st 8 bytes of ciphertext
        ByteArrayRet barCounterBlock = new ByteArrayRet();// byCounterBlock
        barCounterBlock.nLength = 16;
        for (int nLoop = 0; nLoop < 8; nLoop++)
            barCounterBlock.byArray[nLoop] = barBase64Dec.byArray[nLoop];
 
        // generate key schedule
        ByteArrayRet barKeySchedule = KeyExpansion(barCipher);
        
        int nBlockSize = 16;
        int nBlocks = (int)Math.ceil((double)(barBase64Dec.nLength - 8) / nBlockSize);
 
        ByteArrayRet barUTF8Text = new ByteArrayRet();
        //barUTF8Text.nLength = 1024;
        barUTF8Text.nLength = barBase64Dec.nLength;
 
        for (Integer nLoop = 0; nLoop < nBlocks; nLoop++)
        {
            barCounterBlock.byArray[15] = nLoop.byteValue();
            ByteArrayRet barCipherCntr = Cipher(barCounterBlock, barKeySchedule);
 
            for (int nLoop2 = 0; nLoop2 < 16; nLoop2++)
            {
                if ((16 * nLoop + nLoop2 + 8) >= barBase64Dec.nLength)
                    break;
 
                Integer nConvert = barCipherCntr.byArray[nLoop2] ^ barBase64Dec.byArray[16 * nLoop + nLoop2 + 8];
                barUTF8Text.byArray[16 * nLoop + nLoop2] = nConvert.byteValue();
            }
        }
 
        // new String (barUTF8Text.byArray) 라고 하지 않고 아래와 같이 하는 것은, 뒤에 붙은 0들 때문에 글자로 바꾸다가 페이지가 죽기 때문이다.
        int nResultLength = 0;
        for (int nLoop = 0; nLoop < barUTF8Text.nLength; nLoop++)
        {
            if (barUTF8Text.byArray[nLoop] == 0)
                break;
 
            nResultLength++;
        }
        
        byte byResult[] = new byte[nResultLength];
        for (int nLoop = 0; nLoop < nResultLength; nLoop++)
            byResult[nLoop] = barUTF8Text.byArray[nLoop];
 
        String strRet = new String (byResult);
 
        return strRet;
    }
 
}
 

 

* AES 알고리즘 사용

더 강한 알려진 알고리즘을 사용해도 된다. 외부에서 필요한 것은

String strEncText = dec.AESEncrypt(Text, "Key");

String strEncText = dec.AESDecrypt(Text, "Key");

톰캣과 안드로이드에서 가져다 쓸수있게 만들어준다.

Java Class 파일을

1. 톰캣설치경로\webapps\웹프로젝트경로\ 에 복사 ( 위치는 상관없음. 최종적으로 컴파일한 후에 class 파일의 위치가 중요함 )

2. 안드로이드 프로젝트 src에 복사 or Java class 파일을 Jar 파일로 만들어서 안드로이드 프로젝트에 import

웹과 안드로이드 프로젝트 환경에서 가져다 쓸수있도록 한다.

웹에서는 단순하게 cmd를 사용했다.

javac -d . Decrypt.java  해서 컴파일하면 

톰캣설치경로\webapps\웹프로젝트경로\com\test\decodeparam\Decrypt.class 가 생성된다. ( 패키지명대로 디렉터리 생성)

java -cp . com.test.decodeparam.Decrypt 해서 실행 확인해본다.

public static void main(String[] args) {
  Decrypt dec = new Decrypt();
  // TODO Auto-generated method stub
  String Text = "TEST";
  System.out.println(Text);
  String strEncText = dec.AESEncrypt(Text, "Key");
  System.out.println(strEncText);
  String strDecText = dec.AESDecrypt(strEncText, "Key");
  System.out.println(strDecText)
}

의 결과는

TEST                 //원문
FrshVxYWFhbjM88g     //암호화문
TEST                 //복호화문

암복호화가 정상적으로 이루어지는 클래스임을 파악했다.

 

 톰캣설치경로\webapps\웹프로젝트경로\에

WEB-INF\classes\ 를 만들고 좀 전에 만든 com 이하 폴더들을 복사해 놓는다.

JSP 안에서 <%@page import="com.test.decodeparam.Decrypt"%> 를 하면

WEB-INF\classes\com\test\decodeparam\Decrypt.class 에서 클래스 파일을 가져와서

Decrypt 클래스를 JSP 상에서 사용할 수 있다.