Android编程加密算法小结(AES、Base64、RAS加密算法)

| (((int) data[i + 2]) & 0x0ff); buf.append(legalChars[(d >> 18) & 63]);

buf.append(legalChars[(d >> 12) & 63]); buf.append(legalChars[(d >> 6) & 63]);

buf.append(legalChars[d & 63]); i += 3;

if (n++ >= 14) { n = 0;

buf.append(" "); }

} if (i == start + len - 2) {

int d = ((((int) data[i]) & 0x0ff) << 16) | ((((int) data[i + 1]) & 255) << 8);

buf.append(legalChars[(d >> 18) & 63]); buf.append(legalChars[(d >> 12) & 63]);

buf.append(legalChars[(d >> 6) & 63]); buf.append("=");

} else if (i == start + len - 1) { int d = (((int) data[i]) & 0x0ff) << 16;

buf.append(legalChars[(d >> 18) & 63]); buf.append(legalChars[(d >> 12) & 63]);

buf.append("=="); }

return buf.toString(); }

private static int decode(char c) { if (c >= 'A' && c <= 'Z')

return ((int) c) - 65; else if (c >= 'a' && c <= 'z')

return ((int) c) - 97 + 26; else if (c >= '0' && c <= '9')

return ((int) c) - 48 + 26 + 26; else

switch (c) { case '+':

return 62; case '/':

return 63; case '=':

return 0; default:

throw new RuntimeException("unexpected code: " + c); }

} public static byte[] decode(String s) {

ByteArrayOutputStream bos = new ByteArrayOutputStream(); try {