微信退款报文AES解密参考代码

package test; import java.io.IOException; import java.io.OutputStream; import java.io.Writer; public class Base64Util { private static final char S_BASE64CHAR[] = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' }; private static final byte S_DECODETABLE[]; static { S_DECODETABLE = new byte[128]; for (int i = 0; i < S_DECODETABLE.length; i++) S_DECODETABLE[i] = 127; for (int i = 0; i < S_BASE64CHAR.length; i++) S_DECODETABLE[S_BASE64CHAR[i]] = (byte) i; } /** * * @param ibuf * @param obuf * @param wp * @return */ private static int decode0(char ibuf[], byte obuf[], int wp) { int outlen = 3; if (ibuf[3] == '=') outlen = 2; if (ibuf[2] == '=') outlen = 1; int b0 = S_DECODETABLE[ibuf[0]]; int b1 = S_DECODETABLE[ibuf[1]]; int b2 = S_DECODETABLE[ibuf[2]]; int b3 = S_DECODETABLE[ibuf[3]]; switch (outlen) { case 1: // '\001' obuf[wp] = (byte) (b0 << 2 & 252 | b1 >> 4 & 3); return 1; case 2: // '\002' obuf[wp++] = (byte) (b0 << 2 & 252 | b1 >> 4 & 3); obuf[wp] = (byte) (b1 << 4 & 240 | b2 >> 2 & 15); return 2; case 3: // '\003' obuf[wp++] = (byte) (b0 << 2 & 252 | b1 >> 4 & 3); obuf[wp++] = (byte) (b1 << 4 & 240 | b2 >> 2 & 15); obuf[wp] = (byte) (b2 << 6 & 192 | b3 & 63); return 3; } throw new RuntimeException("Internal error"); } /** * * @param data * @param off * @param len * @return */ public static byte[] decode(char data[], int off, int len) { char ibuf[] = new char[4]; int ibufcount = 0; byte obuf[] = new byte[(len / 4) * 3 + 3]; int obufcount = 0; for (int i = off; i < off + len; i++) { char ch = data[i]; if (ch != '=' && (ch >= S_DECODETABLE.length || S_DECODETABLE[ch] == 127)) continue; ibuf[ibufcount++] = ch; if (ibufcount == ibuf.length) { ibufcount = 0; obufcount += decode0(ibuf, obuf, obufcount); } } if (obufcount == obuf.length) { return obuf; } else { byte ret[] = new byte[obufcount]; System.arraycopy(obuf, 0, ret, 0, obufcount); return ret; } } /** * * @param data * @return */ public static byte[] decode(String data) { char ibuf[] = new char[4]; int ibufcount = 0; byte obuf[] = new byte[(data.length() / 4) * 3 + 3]; int obufcount = 0; for (int i = 0; i < data.length(); i++) { char ch = data.charAt(i); if (ch != '=' && (ch >= S_DECODETABLE.length || S_DECODETABLE[ch] == 127)) continue; ibuf[ibufcount++] = ch; if (ibufcount == ibuf.length) { ibufcount = 0; obufcount += decode0(ibuf, obuf, obufcount); } } if (obufcount == obuf.length) { return obuf; } else { byte ret[] = new byte[obufcount]; System.arraycopy(obuf, 0, ret, 0, obufcount); return ret; } } /** * * @param data * @param off * @param len * @param ostream * @throws IOException */ public static void decode(char data[], int off, int len, OutputStream ostream) throws IOException { char ibuf[] = new char[4]; int ibufcount = 0; byte obuf[] = new byte[3]; for (int i = off; i < off + len; i++) { char ch = data[i]; if (ch != '=' && (ch >= S_DECODETABLE.length || S_DECODETABLE[ch] == 127)) continue; ibuf[ibufcount++] = ch; if (ibufcount == ibuf.length) { ibufcount = 0; int obufcount = decode0(ibuf, obuf, 0); ostream.write(obuf, 0, obufcount); } } } /** * * @param data * @param ostream * @throws IOException */ public static void decode(String data, OutputStream ostream) throws IOException { char ibuf[] = new char[4]; int ibufcount = 0; byte obuf[] = new byte[3]; for (int i = 0; i < data.length(); i++) { char ch = data.charAt(i); if (ch != '=' && (ch >= S_DECODETABLE.length || S_DECODETABLE[ch] == 127)) continue; ibuf[ibufcount++] = ch; if (ibufcount == ibuf.length) { ibufcount = 0; int obufcount = decode0(ibuf, obuf, 0); ostream.write(obuf, 0, obufcount); } } } /** * * @param data * @return */ public static String encode(byte data[]) { return encode(data, 0, data.length); } /** * * @param data * @param off * @param len * @return */ public static String encode(byte data[], int off, int len) { if (len <= 0) return ""; char out[] = new char[(len / 3) * 4 + 4]; int rindex = off; int windex = 0; int rest; for (rest = len - off; rest >= 3; rest -= 3) { int i = ((data[rindex] & 255) << 16) + ((data[rindex + 1] & 255) << 8) + (data[rindex + 2] & 255); out[windex++] = S_BASE64CHAR[i >> 18]; out[windex++] = S_BASE64CHAR[i >> 12 & 63]; out[windex++] = S_BASE64CHAR[i >> 6 & 63]; out[windex++] = S_BASE64CHAR[i & 63]; rindex += 3; } if (rest == 1) { int i = data[rindex] & 255; out[windex++] = S_BASE64CHAR[i >> 2]; out[windex++] = S_BASE64CHAR[i << 4 & 63]; out[windex++] = '='; out[windex++] = '='; } else if (rest == 2) { int i = ((data[rindex] & 255) << 8) + (data[rindex + 1] & 255); out[windex++] = S_BASE64CHAR[i >> 10]; out[windex++] = S_BASE64CHAR[i >> 4 & 63]; out[windex++] = S_BASE64CHAR[i << 2 & 63]; out[windex++] = '='; } return new String(out, 0, windex); } /** * * @param data * @param off * @param len * @param ostream * @throws IOException */ public static void encode(byte data[], int off, int len, OutputStream ostream) throws IOException { if (len <= 0) return; byte out[] = new byte[4]; int rindex = off; int rest; for (rest = len - off; rest >= 3; rest -= 3) { int i = ((data[rindex] & 255) << 16) + ((data[rindex + 1] & 255) << 8) + (data[rindex + 2] & 255); out[0] = (byte) S_BASE64CHAR[i >> 18]; out[1] = (byte) S_BASE64CHAR[i >> 12 & 63]; out[2] = (byte) S_BASE64CHAR[i >> 6 & 63]; out[3] = (byte) S_BASE64CHAR[i & 63]; ostream.write(out, 0, 4); rindex += 3; } if (rest == 1) { int i = data[rindex] & 255; out[0] = (byte) S_BASE64CHAR[i >> 2]; out[1] = (byte) S_BASE64CHAR[i << 4 & 63]; out[2] = 61; out[3] = 61; ostream.write(out, 0, 4); } else if (rest == 2) { int i = ((data[rindex] & 255) << 8) + (data[rindex + 1] & 255); out[0] = (byte) S_BASE64CHAR[i >> 10]; out[1] = (byte) S_BASE64CHAR[i >> 4 & 63]; out[2] = (byte) S_BASE64CHAR[i << 2 & 63]; out[3] = 61; ostream.write(out, 0, 4); } } /** * * @param data * @param off * @param len * @param writer * @throws IOException */ public static void encode(byte data[], int off, int len, Writer writer) throws IOException { if (len <= 0) return; char out[] = new char[4]; int rindex = off; int rest = len - off; int output = 0; do { if (rest < 3) break; int i = ((data[rindex] & 255) << 16) + ((data[rindex + 1] & 255) << 8) + (data[rindex + 2] & 255); out[0] = S_BASE64CHAR[i >> 18]; out[1] = S_BASE64CHAR[i >> 12 & 63]; out[2] = S_BASE64CHAR[i >> 6 & 63]; out[3] = S_BASE64CHAR[i & 63]; writer.write(out, 0, 4); rindex += 3; rest -= 3; if ((output += 4) % 76 == 0) writer.write("\n"); } while (true); if (rest == 1) { int i = data[rindex] & 255; out[0] = S_BASE64CHAR[i >> 2]; out[1] = S_BASE64CHAR[i << 4 & 63]; out[2] = '='; out[3] = '='; writer.write(out, 0, 4); } else if (rest == 2) { int i = ((data[rindex] & 255) << 8) + (data[rindex + 1] & 255); out[0] = S_BASE64CHAR[i >> 10]; out[1] = S_BA