com.bitpay.sdk.util.KeyUtils Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of bitpay_sdk Show documentation
Show all versions of bitpay_sdk Show documentation
Full implementation of the BitPay Payment Gateway. This library implements BitPay's Cryptographically
Secure RESTful API.
The newest version!
/*
* Copyright (c) 2019 BitPay.
* All rights reserved.
*/
package com.bitpay.sdk.util;
import com.bitpay.sdk.exceptions.BitPayExceptionProvider;
import com.bitpay.sdk.exceptions.BitPayGenericException;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.charset.StandardCharsets;
import org.bitcoinj.core.Base58;
import org.bitcoinj.core.ECKey;
import org.bitcoinj.core.ECKey.ECDSASignature;
import org.bitcoinj.core.Sha256Hash;
import org.bitcoinj.crypto.KeyCrypterException;
/**
* The type Key utils.
*/
public class KeyUtils {
private static final char[] hexArray = "0123456789abcdef".toCharArray();
private static String PrivateKeyFile;
private static URI privateKey;
/**
* Instantiates a new Key utils.
*/
public KeyUtils() {
}
/**
* Check if private key exists.
*
* @param privateKeyFile the private key file
* @return the boolean
*/
public static boolean privateKeyExists(String privateKeyFile) {
PrivateKeyFile = privateKeyFile;
return new File(privateKeyFile).exists();
}
/**
* Create EC key.
*
* @return the ec key
*/
public static ECKey createEcKey() {
//Default constructor uses SecureRandom numbers.
return new ECKey();
}
/**
* Create EC key from hex string.
*
* @param privateKey the private key
* @return the ec key
* @throws BitPayGenericException BitPayGenericException class
*/
public static ECKey createEcKeyFromHexString(String privateKey) throws BitPayGenericException {
byte[] bytes = hexToBytes(privateKey);
return ECKey.fromASN1(bytes);
}
/**
* Create EC key from hex string private key file.
*
* @param privKeyFile the priv key file
* @return the ec key
* @throws BitPayGenericException BitPayGenericException class
* @throws IOException the io exception
*/
public static ECKey createEcKeyFromHexStringFile(String privKeyFile) throws IOException, BitPayGenericException {
return createEcKeyFromHexString(getKeyStringFromFile(privKeyFile));
}
/**
* Load EC key.
*
* @return the ec key
* @throws IOException the io exception
*/
public static ECKey loadEcKey() throws IOException {
FileInputStream fileInputStream;
File file;
if (KeyUtils.privateKey == null) {
file = new File(PrivateKeyFile);
} else {
file = new File(KeyUtils.privateKey);
}
byte[] bytes = new byte[(int) file.length()];
fileInputStream = new FileInputStream(file);
int numBytesRead = fileInputStream.read(bytes);
fileInputStream.close();
if (numBytesRead == -1) {
throw new IOException("read nothing from the file.");
}
return ECKey.fromASN1(bytes);
}
/**
* Load EC key.
*
* @param privateKey the private key
* @return the ec key
* @throws IOException the io exception
* @throws URISyntaxException the uri syntax exception
*/
public static ECKey loadEcKey(URI privateKey) throws IOException, URISyntaxException {
KeyUtils.privateKey = privateKey;
File file = new File(privateKey);
if (!file.exists()) {
ECKey key = createEcKey();
saveEcKey(key, KeyUtils.privateKey);
return key;
}
return loadEcKey();
}
/**
* Gets key string from file.
*
* @param filename the filename
* @return the key string from file
* @throws IOException the io exception
*/
public static String getKeyStringFromFile(String filename) throws IOException {
BufferedReader br;
br = new BufferedReader(new FileReader(filename));
String line = br.readLine();
br.close();
return line;
}
/**
* Save EC key.
*
* @param ecKey the ec key
* @throws IOException the io exception
*/
public static void saveEcKey(ECKey ecKey) throws IOException {
byte[] bytes = ecKey.toASN1();
File file;
if (KeyUtils.privateKey == null) {
file = new File(PrivateKeyFile);
} else {
file = new File(KeyUtils.privateKey);
}
FileOutputStream output = new FileOutputStream(file);
output.write(bytes);
output.close();
}
/**
* Save EC key.
*
* @param ecKey the ec key
* @param privateKey the private key
* @throws IOException the io exception
* @throws URISyntaxException the uri syntax exception
*/
public static void saveEcKey(
ECKey ecKey,
URI privateKey
) throws IOException, URISyntaxException {
File file = new File(privateKey);
//we shan't overwrite an existing file
if (file.exists()) {
return;
}
KeyUtils.privateKey = privateKey;
saveEcKey(ecKey);
}
/**
* Save EC key as hex.
*
* @param ecKey the ec key
* @throws IOException the io exception
*/
public static void saveEcKeyAsHex(ECKey ecKey) throws IOException {
byte[] bytes = ecKey.toASN1();
PrintWriter file;
if (KeyUtils.privateKey == null) {
file = new PrintWriter(PrivateKeyFile);
} else {
file = new PrintWriter(String.valueOf(KeyUtils.privateKey));
}
String keyHex = bytesToHex(bytes);
file.println(keyHex);
file.close();
}
/**
* Load EC key as hex string.
*
* @param ecKey the ec key
* @return the string
* @throws IOException the io exception
*/
public static String loadEcKeyAsHex(ECKey ecKey) throws IOException {
byte[] bytes = ecKey.toASN1();
return bytesToHex(bytes);
}
/**
* Derive sin string.
*
* @param ecKey the ec key
* @return the string
* @throws BitPayGenericException the illegal argument exception
*/
public static String deriveSin(ECKey ecKey) throws BitPayGenericException {
// Get sha256 hash and then the RIPEMD-160 hash of the public key (this call gets the result in one step).
byte[] pubKeyHash = ecKey.getPubKeyHash();
// Convert binary pubKeyHash, SINtype and version to Hex
String version = "0F";
String sinType = "02";
String pubKeyHashHex = bytesToHex(pubKeyHash);
// Concatenate all three elements
String preSin = version + sinType + pubKeyHashHex;
// Convert the hex string back to binary and double sha256 hash it leaving in binary both times
byte[] preSinByte = hexToBytes(preSin);
byte[] hash2Bytes = Sha256Hash.hashTwice(preSinByte);
// Convert back to hex and take first four bytes
String hashString = bytesToHex(hash2Bytes);
String first4Bytes = hashString.substring(0, 8);
// Append first four bytes to fully appended SIN string
String unencoded = preSin + first4Bytes;
byte[] unencodedBytes = new BigInteger(unencoded, 16).toByteArray();
return Base58.encode(unencodedBytes);
}
/**
* Sign EC Key.
*
* @param key the key
* @param input the input
* @return the string
* @throws BitPayGenericException BitPayGenericException class
*/
public static String sign(
ECKey key,
String input
) throws BitPayGenericException {
String result = null;
try {
byte[] data = input.getBytes(StandardCharsets.UTF_8);
Sha256Hash hash = Sha256Hash.of(data);
ECDSASignature sig = key.sign(hash, null);
byte[] bytes = sig.encodeToDER();
result = bytesToHex(bytes);
} catch (KeyCrypterException e) {
BitPayExceptionProvider.throwGenericExceptionWithMessage("Wrong ecKey. " + e.getMessage());
}
return result;
}
private static int getHexVal(char hex) {
int val = hex;
return val - (val < 58 ? 48 : (val < 97 ? 55 : 87));
}
/**
* Convert hex to bytes.
*
* @param hex the hex
* @return the byte []
* @throws BitPayGenericException BitPayGenericException class
*/
public static byte[] hexToBytes(String hex) throws BitPayGenericException {
char[] hexArray = hex.toCharArray();
if (hex.length() % 2 == 1) {
BitPayExceptionProvider.throwGenericExceptionWithMessage(
"Error: The binary key cannot have an odd number of digits");
}
byte[] arr = new byte[hex.length() >> 1];
for (int i = 0; i < hex.length() >> 1; ++i) {
arr[i] = (byte) ((getHexVal(hexArray[i << 1]) << 4) + (getHexVal(hexArray[(i << 1) + 1])));
}
return arr;
}
/**
* Convert bytes to hex.
*
* @param bytes the bytes
* @return the string
*/
public static String bytesToHex(byte[] bytes) {
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
}