对于javascript中的import android.util.Log;
import org.bouncycastle.bcpg.ArmoredOutputStream;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openpgp.PGPCompressedDataGenerator;
import org.bouncycastle.openpgp.PGPEncryptedData;
import org.bouncycastle.openpgp.PGPEncryptedDataGenerator;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPLiteralData;
import org.bouncycastle.openpgp.PGPLiteralDataGenerator;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyRing;
import org.bouncycastle.openpgp.PGPPublicKeyRingCollection;
import org.bouncycastle.openpgp.PGPUtil;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Date;
import java.util.Iterator;
import static android.support.constraint.Constraints.TAG;
public class RSAEncryption {
static dataToBeEncrypt = "Hello";
static String publickey = "-----BEGIN PGP PUBLIC KEY BLOCK-----\n" +
"\n" +
"mI0EXEr27gEEALybxOEubZ39PX1t+oU9iXhTTmqrc/+ha+J6TYd+yvYcNEBIOzPI\n" +
"1fG2Tz30zJYwT9uZOyW7LAGKRcsIH6p4SiKGaEYBLEWuCQrGfXPAAXaH+WNsKOmz\n" +
"SAZilPwugEcWknIUDZzfU0AD8PPCLqhJM6Ij7AJ/SNa2xUIsyUW+PwBdABEBAAG0\n" +
"BWplZXRziM4EEwEKADgWIQRp0+dcK5ZTXht9TIcw0CiFbn2j6gUCXEr27gIbAwUL\n" +
"CQgHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRAw0CiFbn2j6um7A/9Ttzl8xHa4MvuF\n" +
"htOEAb6sXOk17B9BQyd3bkUCYtBjmFA3Q7XzWln5lm2QQTxW+AnlVJYwQS5zvVC0\n" +
"8WgPh6XP9sCi6/2ar748wpS8dL1wEAwaMOSYGEDCUpmW2uEGsrsAKfiMlKGhLiPC\n" +
"uUvPJ0x2jjHn9HHO1e9BES9tlkRPJLiNBFxK9u4BBADQtF6EajJMi2IPsVDR6PTX\n" +
"swjGgVbYKqwZRUwfLecJ95VeiQzznWUMpWFze4ESlAjCYeJf37voDazs6Ol5Uqz7\n" +
"7d5GurEk4kNjQp4Pm+chFQWLWU1seMghyJqsXCjWApy0lNJ2YPNbYKUqdJsZpJgT\n" +
"7qofPvEEPlGRRqzZxdN8oQARAQABiLYEGAEKACAWIQRp0+dcK5ZTXht9TIcw0CiF\n" +
"bn2j6gUCXEr27gIbDAAKCRAw0CiFbn2j6ky9BACgADAD/VIFIUjuQtNa4GEcAS0T\n" +
"vtJvsL26qW/Gohl5nb1ix7MLBwiH/l1Co6K52GKAVUrZBCnjkJW5zyGTKUkPGbGY\n" +
"Loh481phsvpYgXHqol7UQivBoF14EO1dNmn61QFRn7D3zhNirziOKQl3kLSuEdc5\n" +
"VpRF7ubkHL3jRrdQFA==\n" +
"=/lmV\n" +
"-----END PGP PUBLIC KEY BLOCK-----";
public static void main (String[] args){
String encrypted = null;
try {
encrypted = encryptToFile(dataToBeEncrypt, publicKey);
} catch (Exception e) {
Log.i(TAG, "Exception: " + e);
}
return encrypted;
}
public static String encryptToFile(String inputdata, String keyFile) throws Exception {
Security.addProvider(new BouncyCastleProvider());
byte[] original = inputdata.getBytes();
InputStream secKey = new ByteArrayInputStream(keyFile.getBytes("UTF-8"));
byte[] encrypted = encrypt(original, readPublicKey(secKey), true, true);
return new String(encrypted);
}
private static PGPPublicKey readPublicKey(InputStream in) throws IOException, PGPException {
PGPPublicKey k = null;
in = PGPUtil.getDecoderStream(in);
PGPPublicKeyRingCollection pgpPub = new PGPPublicKeyRingCollection(in);
Iterator rIt = pgpPub.getKeyRings();
while (rIt.hasNext()) {
PGPPublicKeyRing kRing = (PGPPublicKeyRing) rIt.next();
Iterator kIt = kRing.getPublicKeys();
while (kIt.hasNext()) {
k = (PGPPublicKey) kIt.next();
if (k.isEncryptionKey()) {
break;
}
}
}
return k;
}
/**
* Simple PGP encryptor between byte[].
*
* @param clearData
* The test to be encrypted
* @param //passPhrase
* The pass phrase (key). This method assumes that the key is a
* simple pass phrase, and does not yet support RSA or more
* sophisiticated keying.
* @param //fileName
* File name. This is used in the Literal Data Packet (tag 11)
* which is really inly important if the data is to be related to
* a file to be recovered later. Because this routine does not
* know the source of the information, the caller can set
* something here for file name use that will be carried. If this
* routine is being used to encrypt SOAP MIME bodies, for
* example, use the file name from the MIME type, if applicable.
* Or anything else appropriate.
*
* @param armor
* @return encrypted data.
* @exception IOException
* @exception PGPException
* @exception NoSuchProviderException
*/
public static byte[] encrypt(byte[] clearData, PGPPublicKey encKey, boolean withIntegrityCheck, boolean armor)
throws IOException, PGPException, NoSuchProviderException {
ByteArrayOutputStream encOut = new ByteArrayOutputStream();
OutputStream out = encOut;
if (armor) {
out = new ArmoredOutputStream(out);
}
ByteArrayOutputStream bOut = new ByteArrayOutputStream();
PGPCompressedDataGenerator comData = new PGPCompressedDataGenerator(
PGPCompressedDataGenerator.ZIP);
OutputStream cos = comData.open(bOut); // open it with the final
// destination
PGPLiteralDataGenerator lData = new PGPLiteralDataGenerator();
// we want to generate compressed data. This might be a user option
// later,
// in which case we would pass in bOut.
OutputStream pOut = lData.open(cos, // the compressed output stream
PGPLiteralData.BINARY, "", // "filename" to store
clearData.length, // length of clear data
new Date() // current time
);
pOut.write(clearData);
lData.close();
comData.close();
PGPEncryptedDataGenerator cPk = new PGPEncryptedDataGenerator(
PGPEncryptedData.AES_128, withIntegrityCheck, new SecureRandom(),
"BC");
cPk.addMethod(encKey);
byte[] bytes = bOut.toByteArray();
OutputStream cOut = cPk.open(out, bytes.length);
cOut.write(bytes); // obtain the actual bytes from the compressed stream
cOut.close();
out.close();
return encOut.toByteArray();
}
}
值（例如，指数是11111111111），有什么方法可以获取符号位和有效值（忽略隐式的1位）吗？
如果不是这种情况，是否表示javascript中的NaN并不代表double (Number)可能的状态，而是（2^64）可能的状态？
答案 0 :(得分：1)
正如Heretic Monkey所指出的，该规范特别指出，JavaScript中的NaN数几乎无法区分-
“在某些实现中，外部代码可能能够检测到各种非数字值之间的差异，但是这种行为取决于实现；对于ECMAScript代码，所有NaN值彼此之间是无法区分的。” >
https://www.ecma-international.org/ecma-262/6.0/#sec-ecmascript-language-types-number-type
因此，这似乎是不可能的，或者至少不可能以平台无关的方式。
一个建议是使用类型化数组。这似乎可以在IE和Chrome中使用，但不能在Firefox中使用！问题是当您将double存储在变量中时，在firefox中，它将丢失为NaN值设置的所有位模式...
var buffer = new ArrayBuffer(8);
var floats = new Float64Array(buffer);
var bytes = new Uint8Array(buffer);
floats[0] = NaN;
var print_float_bytes = function() {
var pstr = "";
for (var i = 0; i < 8; i += 1) {
pstr = pstr + " " + bytes[i];
}
console.log(pstr);
};
console.log("printing a fresh NaN");
print_float_bytes();
bytes[7] = 255;
console.log("printing a NaN with the sign bit as 1");
print_float_bytes();
bytes[0] = 1;
console.log("printing a NaN with the significand as a number slightly bigger than 1 and a positive sign");
print_float_bytes();
console.log("printing the floating point number: " + floats[0]);
var p = floats[0];
floats[0] = p;
console.log("printing roundtripped NaN");
print_float_bytes();
var pointless = function(pdbl) {
return pdbl;
};
p = floats[0];
p = pointless(p);
floats[0] = p;
console.log("printing even more roundtripped NaN");
print_float_bytes();