asaph

#!/bin/sh
openssl req -new -newkey rsa:2048 -nodes -days 365 -x509 -subj "/C=/ST=/L=/O=/CN=localhost" -keyout privkey.pem -out cacert.pem

asaph

#!/bin/sh
keytool -genkey -validity 365 -alias "youralias" -keyalg "RSA" -keystore .keystore -keypass "yourkeypass" -storepass "yourstorepass" -dname "CN=localhost, OU=, O=, L=, S=, C="

asaph

#!/bin/sh
mysql databasename -h hostname -u username -p -B -e "select * from mytable;" > /tmp/myreport.tsv

asaph

<dependency>
    <groupId>commons-codec</groupId>
    <artifactId>commons-codec</artifactId>
    <version>1.10</version>
</dependency>

asaph

public static String getRandomSecretKey() {
    SecureRandom random = new SecureRandom();
    byte[] bytes = new byte[20];
    random.nextBytes(bytes);
    Base32 base32 = new Base32();
    String secretKey = base32.encodeToString(bytes);
    // make the secret key more human-readable by lower-casing and
    // inserting spaces between each group of 4 characters
    return secretKey.toLowerCase().replaceAll("(.{4})(?=.{4})", "$1 ");
}

asaph

public static String getTOTPCode(String secretKey) {
    String normalizedBase32Key = secretKey.replace(" ", "").toUpperCase();
    Base32 base32 = new Base32();
    byte[] bytes = base32.decode(normalizedBase32Key);
    String hexKey = Hex.encodeHexString(bytes);
    long time = (System.currentTimeMillis() / 1000) / 30;
    String hexTime = Long.toHexString(time);
    return TOTP.generateTOTP(hexKey, hexTime, "6");
}

asaph

String secretKey = "quu6 ea2g horg md22 sn2y ku6v kisc kyag";
String lastCode = null;
while (true) {
    String code = getTOTPCode(secretKey);
    if (!code.equals(lastCode)) {
        // output a new 6 digit code
        System.out.println(code);
    }
    lastCode = code;
    try {

asaph

<dependency>
    <groupId>com.google.zxing</groupId>
    <artifactId>javase</artifactId>
    <version>3.2.1</version>
</dependency>

asaph

public static String getGoogleAuthenticatorBarCode(String secretKey, String account, String issuer) {
    String normalizedBase32Key = secretKey.replace(" ", "").toUpperCase();
    try {
        return "otpauth://totp/"
        + URLEncoder.encode(issuer + ":" + account, "UTF-8").replace("+", "%20")
        + "?secret=" + URLEncoder.encode(normalizedBase32Key, "UTF-8").replace("+", "%20")
        + "&issuer=" + URLEncoder.encode(issuer, "UTF-8").replace("+", "%20");
    } catch (UnsupportedEncodingException e) {
        throw new IllegalStateException(e);
    }

asaph

public static void createQRCode(String barCodeData, String filePath, int height, int width)
            throws WriterException, IOException {
    BitMatrix matrix = new MultiFormatWriter().encode(barCodeData, BarcodeFormat.QR_CODE,
            width, height);
    try (FileOutputStream out = new FileOutputStream(filePath)) {
        MatrixToImageWriter.writeToStream(matrix, "png", out);
    }
}