Base64 加密解密

来源：互联网发布：iphone图片加密软件编辑：程序博客网时间：2024/05/18 01:27

在过去的一年里我还是一个比较喜欢自己发明轮子的人，不过现在不同了。前几天需要个Base64处理类，在一个开源项目里面找到了Base64的加密解密程序感觉非常不错，毕竟不喜欢引入sun.开头的包。
原文网址：http://blog.csdn.net/sunyujia/archive/2008/01/01/2008469.aspx
import java.util.Arrays;

/**

* A very fast and memory efficient class to encode and decode to and from

* BASE64 in full accordance with RFC 2045. 

* 

* On Windows XP sp1 with 1.4.2_04 and later ;), this encoder and decoder is

* about 10 times faster on small arrays (10 - 1000 bytes) and 2-3 times as fast

* on larger arrays (10000 - 1000000 bytes) compared to

* <code>sun.misc.Encoder()/Decoder()</code>. 

* 

*

* On byte arrays the encoder is about 20% faster than Jakarta Commons Base64

* Codec for encode and about 50% faster for decoding large arrays. This

* implementation is about twice as fast on very small arrays (< 30 bytes). If

* source/destination is a <code>String</code> this version is about three

* times as fast due to the fact that the Commons Codec result has to be recoded

* to a <code>String</code> from <code>byte[]</code>, which is very

* expensive. 

* 

*

* This encode/decode algorithm doesn't create any temporary arrays as many

* other codecs do, it only allocates the resulting array. This produces less

* garbage and it is possible to handle arrays twice as large as algorithms that

* create a temporary array. (E.g. Jakarta Commons Codec). It is unknown whether

* Sun's <code>sun.misc.Encoder()/Decoder()</code> produce temporary arrays

* but since performance is quite low it probably does. 

* 

*

* The encoder produces the same output as the Sun one except that the Sun's

* encoder appends a trailing line separator if the last character isn't a pad.

* Unclear why but it only adds to the length and is probably a side effect.

* Both are in conformance with RFC 2045 though. 

* Commons codec seem to always att a trailing line separator. 

* 

*

* Note! The encode/decode method pairs (types) come in three versions

* with the exact same algorithm and thus a lot of code redundancy. This

* is to not create any temporary arrays for transcoding to/from different

* format types. The methods not used can simply be commented out. 

* 

*

* There is also a "fast" version of all decode methods that works the same way

* as the normal ones, but har a few demands on the decoded input. Normally

* though, these fast verions should be used if the source if the input is known

* and it hasn't bee tampered with. 

* 

*

* If you find the code useful or you find a bug, please send me a note at

* base64 @ miginfocom . com.

*

* Licence (BSD): ==============

*

* Copyright (c) 2004, Mikael Grev, MiG InfoCom AB. (base64 @ miginfocom . com)

* All rights reserved.

*

* Redistribution and use in source and binary forms, with or without

* modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this

* list of conditions and the following disclaimer. Redistributions in binary

* form must reproduce the above copyright notice, this list of conditions and

* the following disclaimer in the documentation and/or other materials provided

* with the distribution. Neither the name of the MiG InfoCom AB nor the names

* of its contributors may be used to endorse or promote products derived from

* this software without specific prior written permission.

*

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN

* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

* POSSIBILITY OF SUCH DAMAGE.

*

* @version 2.2

* @author Mikael Grev Date: 2004-aug-02 Time: 11:31:11

*/

public class Base64 {

 private static final boolean devLineSep = true;

 private static final char[] CA = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

 .toCharArray();

 private static final int[] IA = new int[256];

 static {

 Arrays.fill(IA, -1);

 for (int i = 0, iS = CA.length; i < iS; i++)

 IA[CA[i]] = i;

 IA['='] = 0;

 }

 // ****************************************************************************************

 // * char[] version

 // ****************************************************************************************

 public final static char[] encodeToChar(byte[] sArr) {

 return encodeToChar(sArr, devLineSep);

 }

 /**

 * Encodes a raw byte array into a BASE64 <code>char[]</code>

 * representation i accordance with RFC 2045.

 *

 * @param sArr

 * The bytes to convert. If <code>null</code> or length 0 an

 * empty array will be returned.

 * @param lineSep

 * Optional "\r\n" after 76 characters, unless end of file. 

 * No line separator will be in breach of RFC 2045 which

 * specifies max 76 per line but will be a little faster.

 * @return A BASE64 encoded array. Never <code>null</code>.

 */

 public final static char[] encodeToChar(byte[] sArr, boolean lineSep) {

 // Check special case

 int sLen = sArr != null ? sArr.length : 0;

 if (sLen == 0)

 return new char[0];

 int eLen = (sLen / 3) * 3; // Length of even 24-bits.

 int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count

 int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of

 // returned

 // array

 char[] dArr = new char[dLen];

 // Encode even 24-bits

 for (int s = 0, d = 0, cc = 0; s < eLen;) {

 // Copy next three bytes into lower 24 bits of int, paying attension

 // to sign.

 int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8

 | (sArr[s++] & 0xff);

 // Encode the int into four chars

 dArr[d++] = CA[(i >>> 18) & 0x3f];

 dArr[d++] = CA[(i >>> 12) & 0x3f];

 dArr[d++] = CA[(i >>> 6) & 0x3f];

 dArr[d++] = CA[i & 0x3f];

 // Add optional line separator

 if (lineSep && ++cc == 19 && d < dLen - 2) {

 dArr[d++] = '\r';

 dArr[d++] = '\n';

 cc = 0;

 }

 }

 // Pad and encode last bits if source isn't even 24 bits.

 int left = sLen - eLen; // 0 - 2.

 if (left > 0) {

 // Prepare the int

 int i = ((sArr[eLen] & 0xff) << 10)

 | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);

 // Set last four chars

 dArr[dLen - 4] = CA[i >> 12];

 dArr[dLen - 3] = CA[(i >>> 6) & 0x3f];

 dArr[dLen - 2] = left == 2 ? CA[i & 0x3f] : '=';

 dArr[dLen - 1] = '=';

 }

 return dArr;

 }

 /**

 * Decodes a BASE64 encoded char array. All illegal characters will be

 * ignored and can handle both arrays with and without line separators.

 *

 * @param sArr

 * The source array. <code>null</code> or length 0 will return

 * an empty array.

 * @return The decoded array of bytes. May be of length 0. Will be

 * <code>null</code> if the legal characters (including '=') isn't

 * divideable by 4. (I.e. definitely corrupted).

 */

 public final static byte[] decode(char[] sArr) {

 // Check special case

 int sLen = sArr != null ? sArr.length : 0;

 if (sLen == 0)

 return new byte[0];

 // Count illegal characters (including '\r', '\n') to know what size the

 // returned array will be,

 // so we don't have to reallocate & copy it later.

 int sepCnt = 0; // Number of separator characters. (Actually illegal

 // characters, but that's a bonus...)

 for (int i = 0; i < sLen; i++)

 // If input is "pure" (I.e. no line separators or illegal chars)

 // base64 this loop can be commented out.

 if (IA[sArr[i]] < 0)

 sepCnt++;

 // Check so that legal chars (including '=') are evenly divideable by 4

 // as specified in RFC 2045.

 if ((sLen - sepCnt) % 4 != 0)

 return null;

 int pad = 0;

 for (int i = sLen; i > 1 && IA[sArr[--i]] <= 0;)

 if (sArr[i] == '=')

 pad++;

 int len = ((sLen - sepCnt) * 6 >> 3) - pad;

 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

 for (int s = 0, d = 0; d < len;) {

 // Assemble three bytes into an int from four "valid" characters.

 int i = 0;

 for (int j = 0; j < 4; j++) { // j only increased if a valid char

 // was found.

 int c = IA[sArr[s++]];

 if (c >= 0)

 i |= c << (18 - j * 6);

 else

 j--;

 }

 // Add the bytes

 dArr[d++] = (byte) (i >> 16);

 if (d < len) {

 dArr[d++] = (byte) (i >>

;

 if (d < len)

 dArr[d++] = (byte) i;

 }

 }

 return dArr;

 }

 /**

 * Decodes a BASE64 encoded char array that is known to be resonably well

 * formatted. The method is about twice as fast as {@link #decode(char[])}.

 * The preconditions are: + The array must have a line length of 76

 * chars OR no line separators at all (one line). + Line separator must

 * be "\r\n", as specified in RFC 2045 + The array must not contain illegal

 * characters within the encoded string + The array CAN have illegal

 * characters at the beginning and end, those will be dealt with

 * appropriately. 

 *

 * @param sArr

 * The source array. Length 0 will return an empty array.

 * <code>null</code> will throw an exception.

 * @return The decoded array of bytes. May be of length 0.

 */

 public final static byte[] decodeFast(char[] sArr) {

 // Check special case

 int sLen = sArr.length;

 if (sLen == 0)

 return new byte[0];

 int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.

 // Trim illegal chars from start

 while (sIx < eIx && IA[sArr[sIx]] < 0)

 sIx++;

 // Trim illegal chars from end

 while (eIx > 0 && IA[sArr[eIx]] < 0)

 eIx--;

 // get the padding count (=) (0, 1 or 2)

 int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count

 // '='

 // at

 // end.

 int cCnt = eIx - sIx + 1; // Content count including possible

 // separators

 int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;

 int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded

 // bytes

 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

 // Decode all but the last 0 - 2 bytes.

 int d = 0;

 for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {

 // Assemble three bytes into an int from four "valid" characters.

 int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12

 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];

 // Add the bytes

 dArr[d++] = (byte) (i >> 16);

 dArr[d++] = (byte) (i >>

;

 dArr[d++] = (byte) i;

 // If line separator, jump over it.

 if (sepCnt > 0 && ++cc == 19) {

 sIx += 2;

 cc = 0;

 }

 }

 if (d < len) {

 // Decode last 1-3 bytes (incl '=') into 1-3 bytes

 int i = 0;

 for (int j = 0; sIx <= eIx - pad; j++)

 i |= IA[sArr[sIx++]] << (18 - j * 6);

 for (int r = 16; d < len; r -=

dArr[d++] = (byte) (i >> r);

 }

 return dArr;

 }

 // ****************************************************************************************

 // * byte[] version

 // ****************************************************************************************

 public final static byte[] encodeToByte(byte[] sArr) {

 return encodeToByte(sArr, devLineSep);

 }

 /**

 * Encodes a raw byte array into a BASE64 <code>byte[]</code>

 * representation i accordance with RFC 2045.

 *

 * @param sArr

 * The bytes to convert. If <code>null</code> or length 0 an

 * empty array will be returned.

 * @param lineSep

 * Optional "\r\n" after 76 characters, unless end of file. 

 * No line separator will be in breach of RFC 2045 which

 * specifies max 76 per line but will be a little faster.

 * @return A BASE64 encoded array. Never <code>null</code>.

 */

 public final static byte[] encodeToByte(byte[] sArr, boolean lineSep) {

 // Check special case

 int sLen = sArr != null ? sArr.length : 0;

 if (sLen == 0)

 return new byte[0];

 int eLen = (sLen / 3) * 3; // Length of even 24-bits.

 int cCnt = ((sLen - 1) / 3 + 1) << 2; // Returned character count

 int dLen = cCnt + (lineSep ? (cCnt - 1) / 76 << 1 : 0); // Length of

 // returned

 // array

 byte[] dArr = new byte[dLen];

 // Encode even 24-bits

 for (int s = 0, d = 0, cc = 0; s < eLen;) {

 // Copy next three bytes into lower 24 bits of int, paying attension

 // to sign.

 int i = (sArr[s++] & 0xff) << 16 | (sArr[s++] & 0xff) << 8

 | (sArr[s++] & 0xff);

 // Encode the int into four chars

 dArr[d++] = (byte) CA[(i >>> 18) & 0x3f];

 dArr[d++] = (byte) CA[(i >>> 12) & 0x3f];

 dArr[d++] = (byte) CA[(i >>> 6) & 0x3f];

 dArr[d++] = (byte) CA[i & 0x3f];

 // Add optional line separator

 if (lineSep && ++cc == 19 && d < dLen - 2) {

 dArr[d++] = '\r';

 dArr[d++] = '\n';

 cc = 0;

 }

 }

 // Pad and encode last bits if source isn't an even 24 bits.

 int left = sLen - eLen; // 0 - 2.

 if (left > 0) {

 // Prepare the int

 int i = ((sArr[eLen] & 0xff) << 10)

 | (left == 2 ? ((sArr[sLen - 1] & 0xff) << 2) : 0);

 // Set last four chars

 dArr[dLen - 4] = (byte) CA[i >> 12];

 dArr[dLen - 3] = (byte) CA[(i >>> 6) & 0x3f];

 dArr[dLen - 2] = left == 2 ? (byte) CA[i & 0x3f] : (byte) '=';

 dArr[dLen - 1] = '=';

 }

 return dArr;

 }

 /**

 * Decodes a BASE64 encoded byte array. All illegal characters will be

 * ignored and can handle both arrays with and without line separators.

 *

 * @param sArr

 * The source array. Length 0 will return an empty array.

 * <code>null</code> will throw an exception.

 * @return The decoded array of bytes. May be of length 0. Will be

 * <code>null</code> if the legal characters (including '=') isn't

 * divideable by 4. (I.e. definitely corrupted).

 */

 public final static byte[] decode(byte[] sArr) {

 // Check special case

 int sLen = sArr.length;

 // Count illegal characters (including '\r', '\n') to know what size the

 // returned array will be,

 // so we don't have to reallocate & copy it later.

 int sepCnt = 0; // Number of separator characters. (Actually illegal

 // characters, but that's a bonus...)

 for (int i = 0; i < sLen; i++)

 // If input is "pure" (I.e. no line separators or illegal chars)

 // base64 this loop can be commented out.

 if (IA[sArr[i] & 0xff] < 0)

 sepCnt++;

 // Check so that legal chars (including '=') are evenly divideable by 4

 // as specified in RFC 2045.

 if ((sLen - sepCnt) % 4 != 0)

 return null;

 int pad = 0;

 for (int i = sLen; i > 1 && IA[sArr[--i] & 0xff] <= 0;)

 if (sArr[i] == '=')

 pad++;

 int len = ((sLen - sepCnt) * 6 >> 3) - pad;

 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

 for (int s = 0, d = 0; d < len;) {

 // Assemble three bytes into an int from four "valid" characters.

 int i = 0;

 for (int j = 0; j < 4; j++) { // j only increased if a valid char

 // was found.

 int c = IA[sArr[s++] & 0xff];

 if (c >= 0)

 i |= c << (18 - j * 6);

 else

 j--;

 }

 // Add the bytes

 dArr[d++] = (byte) (i >> 16);

 if (d < len) {

 dArr[d++] = (byte) (i >>

;

 if (d < len)

 dArr[d++] = (byte) i;

 }

 }

 return dArr;

 }

 /**

 * Decodes a BASE64 encoded byte array that is known to be resonably well

 * formatted. The method is about twice as fast as {@link #decode(byte[])}.

 * The preconditions are: + The array must have a line length of 76

 * chars OR no line separators at all (one line). + Line separator must

 * be "\r\n", as specified in RFC 2045 + The array must not contain illegal

 * characters within the encoded string + The array CAN have illegal

 * characters at the beginning and end, those will be dealt with

 * appropriately. 

 *

 * @param sArr

 * The source array. Length 0 will return an empty array.

 * <code>null</code> will throw an exception.

 * @return The decoded array of bytes. May be of length 0.

 */

 public final static byte[] decodeFast(byte[] sArr) {

 // Check special case

 int sLen = sArr.length;

 if (sLen == 0)

 return new byte[0];

 int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.

 // Trim illegal chars from start

 while (sIx < eIx && IA[sArr[sIx] & 0xff] < 0)

 sIx++;

 // Trim illegal chars from end

 while (eIx > 0 && IA[sArr[eIx] & 0xff] < 0)

 eIx--;

 // get the padding count (=) (0, 1 or 2)

 int pad = sArr[eIx] == '=' ? (sArr[eIx - 1] == '=' ? 2 : 1) : 0; // Count

 // '='

 // at

 // end.

 int cCnt = eIx - sIx + 1; // Content count including possible

 // separators

 int sepCnt = sLen > 76 ? (sArr[76] == '\r' ? cCnt / 78 : 0) << 1 : 0;

 int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded

 // bytes

 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

 // Decode all but the last 0 - 2 bytes.

 int d = 0;

 for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {

 // Assemble three bytes into an int from four "valid" characters.

 int i = IA[sArr[sIx++]] << 18 | IA[sArr[sIx++]] << 12

 | IA[sArr[sIx++]] << 6 | IA[sArr[sIx++]];

 // Add the bytes

 dArr[d++] = (byte) (i >> 16);

 dArr[d++] = (byte) (i >>

dArr[d++] = (byte) (i >> r);

 }

 return dArr;

 }

 // ****************************************************************************************

 // * String version

 // ****************************************************************************************

 /**

 * Encodes a raw byte array into a BASE64 <code>String</code>

 * representation i accordance with RFC 2045.

 *

 * @param sArr

 * The bytes to convert. If <code>null</code> or length 0 an

 * empty array will be returned.

 * @param lineSep

 * Optional "\r\n" after 76 characters, unless end of file. 

 * No line separator will be in breach of RFC 2045 which

 * specifies max 76 per line but will be a little faster.

 * @return A BASE64 encoded array. Never <code>null</code>.

 */

 public final static String encodeToString(byte[] sArr, boolean lineSep) {

 // Reuse char[] since we can't create a String incrementally anyway and

 // StringBuffer/Builder would be slower.

 return new String(encodeToChar(sArr, lineSep));

 }

 public final static String encodeToString(byte[] sArr) {

 // Reuse char[] since we can't create a String incrementally anyway and

 // StringBuffer/Builder would be slower.

 return new String(encodeToChar(sArr, devLineSep));

 }

 /**

 * Decodes a BASE64 encoded <code>String</code>. All illegal characters

 * will be ignored and can handle both strings with and without line

 * separators. 

 * Note! It can be up to about 2x the speed to call

 * <code>decode(str.toCharArray())</code> instead. That will create a

 * temporary array though. This version will use <code>str.charAt(i)</code>

 * to iterate the string.

 *

 * @param str

 * The source string. <code>null</code> or length 0 will return

 * an empty array.

 * @return The decoded array of bytes. May be of length 0. Will be

 * <code>null</code> if the legal characters (including '=') isn't

 * divideable by 4. (I.e. definitely corrupted).

 */

 public final static byte[] decode(String str) {

 // Check special case

 int sLen = str != null ? str.length() : 0;

 if (sLen == 0)

 return new byte[0];

 // Count illegal characters (including '\r', '\n') to know what size the

 // returned array will be,

 // so we don't have to reallocate & copy it later.

 int sepCnt = 0; // Number of separator characters. (Actually illegal

 // characters, but that's a bonus...)

 for (int i = 0; i < sLen; i++)

 // If input is "pure" (I.e. no line separators or illegal chars)

 // base64 this loop can be commented out.

 if (IA[str.charAt(i)] < 0)

 sepCnt++;

 // Check so that legal chars (including '=') are evenly divideable by 4

 // as specified in RFC 2045.

 if ((sLen - sepCnt) % 4 != 0)

 return null;

 // Count '=' at end

 int pad = 0;

 for (int i = sLen; i > 1 && IA[str.charAt(--i)] <= 0;)

 if (str.charAt(i) == '=')

 pad++;

 int len = ((sLen - sepCnt) * 6 >> 3) - pad;

 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

 for (int s = 0, d = 0; d < len;) {

 // Assemble three bytes into an int from four "valid" characters.

 int i = 0;

 for (int j = 0; j < 4; j++) { // j only increased if a valid char

 // was found.

 int c = IA[str.charAt(s++)];

 if (c >= 0)

 i |= c << (18 - j * 6);

 else

 j--;

 }

 // Add the bytes

 dArr[d++] = (byte) (i >> 16);

 if (d < len) {

 dArr[d++] = (byte) (i >>

;

 if (d < len)

 dArr[d++] = (byte) i;

 }

 }

 return dArr;

 }

 /**

 * Decodes a BASE64 encoded string that is known to be resonably well

 * formatted. The method is about twice as fast as {@link #decode(String)}.

 * The preconditions are: + The array must have a line length of 76

 * chars OR no line separators at all (one line). + Line separator must

 * be "\r\n", as specified in RFC 2045 + The array must not contain illegal

 * characters within the encoded string + The array CAN have illegal

 * characters at the beginning and end, those will be dealt with

 * appropriately. 

 *

 * @param s

 * The source string. Length 0 will return an empty array.

 * <code>null</code> will throw an exception.

 * @return The decoded array of bytes. May be of length 0.

 */

 public final static byte[] decodeFast(String s) {

 // Check special case

 int sLen = s.length();

 if (sLen == 0)

 return new byte[0];

 int sIx = 0, eIx = sLen - 1; // Start and end index after trimming.

 // Trim illegal chars from start

 while (sIx < eIx && IA[s.charAt(sIx) & 0xff] < 0)

 sIx++;

 // Trim illegal chars from end

 while (eIx > 0 && IA[s.charAt(eIx) & 0xff] < 0)

 eIx--;

 // get the padding count (=) (0, 1 or 2)

 int pad = s.charAt(eIx) == '=' ? (s.charAt(eIx - 1) == '=' ? 2 : 1) : 0; // Count

 // '='

 // at

 // end.

 int cCnt = eIx - sIx + 1; // Content count including possible

 // separators

 int sepCnt = sLen > 76 ? (s.charAt(76) == '\r' ? cCnt / 78 : 0) << 1

 : 0;

 int len = ((cCnt - sepCnt) * 6 >> 3) - pad; // The number of decoded

 // bytes

 byte[] dArr = new byte[len]; // Preallocate byte[] of exact length

 // Decode all but the last 0 - 2 bytes.

 int d = 0;

 for (int cc = 0, eLen = (len / 3) * 3; d < eLen;) {

 // Assemble three bytes into an int from four "valid" characters.

 int i = IA[s.charAt(sIx++)] << 18 | IA[s.charAt(sIx++)] << 12

 | IA[s.charAt(sIx++)] << 6 | IA[s.charAt(sIx++)];

 // Add the bytes

 dArr[d++] = (byte) (i >> 16);

 dArr[d++] = (byte) (i >>

;

 dArr[d++] = (byte) i;

 // If line separator, jump over it.

 if (sepCnt > 0 && ++cc == 19) {

 sIx += 2;

 cc = 0;

 }

 }

 if (d < len) {

 // Decode last 1-3 bytes (incl '=') into 1-3 bytes

 int i = 0;

 for (int j = 0; sIx <= eIx - pad; j++)

 i |= IA[s.charAt(sIx++)] << (18 - j * 6);

 for (int r = 16; d < len; r -=

                                dArr[d++] = (byte) (i >> r);

                }

                return dArr;

        }

        public static void main(String[] args){

                System.out.println(Base64.encodeToString("5CC9D9B48EFCF2FDB766BFB00E08EEDF".getBytes()));

        }

}

Base64 加密 解密

Base64 加密解密