Encrypt in Javascript, decrypt in PHP, using public-key cryptography

Question

I\'d like to encrypt in JavaScript, decrypt in PHP, using public-key cryptography. I\'ve been trying to find libraries that can accomplish this, but am having issues.

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Answer 1

RSA example usage for pidCrypt (js) and phpseclib (php).

Do not reuse the private key in this working example.

pidCrypt encryption

//From the pidCrypt example sandbox
function certParser(cert) {
    var lines = cert.split('\n');
    var read = false;
    var b64 = false;
    var end = false;
    var flag = '';
    var retObj = {
    };
    retObj.info = '';
    retObj.salt = '';
    retObj.iv;
    retObj.b64 = '';
    retObj.aes = false;
    retObj.mode = '';
    retObj.bits = 0;
    for (var i = 0; i < lines.length; i++) {
        flag = lines[i].substr(0, 9);
        if (i == 1 && flag != 'Proc-Type' && flag.indexOf('M') == 0)//unencrypted cert?
        b64 = true;
        switch (flag) {
            case '-----BEGI':
                read = true;
                break;
            case 'Proc-Type':
                if (read)retObj.info = lines[i];
                break;
            case 'DEK-Info:':
                if (read) {
                    var tmp = lines[i].split(',');
                    var dek = tmp[0].split(': ');
                    var aes = dek[1].split('-');
                    retObj.aes = (aes[0] == 'AES') ? true : false;
                    retObj.mode = aes[2];
                    retObj.bits = parseInt(aes[1]);
                    retObj.salt = tmp[1].substr(0, 16);
                    retObj.iv = tmp[1];
                }
                break;
            case '':
                if (read)b64 = true;
                break;
            case '-----END ':
                if (read) {
                    b64 = false;
                    read = false;
                }
                break;
                default : if (read && b64)retObj.b64 += pidCryptUtil.stripLineFeeds(lines[i]);
        }
    }
    return retObj;
}

var strCreditCardPublicKey="-----BEGIN PUBLIC KEY-----\nMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC\/tI7cw+gnUPK2LqWp50XboJ1i\njrLDn+4\/gPOe+pB5kz4VJX2KWwg9iYMG9UJ1M+AeN33qT7xt9ob2dxgtTh7Mug2S\nn1TLz4donuIzxCmW+SZdU1Y+WNDINds194hWsAVhMC1ClMQTfldUGzQnI5sXvZTF\nJWp\/9jheCNLDRIkAnQIDAQAB\n-----END PUBLIC KEY-----\n";

var objParams=certParser(strCreditCardPublicKey);
var binaryPrivateKey=pidCryptUtil.decodeBase64(objParams.b64);

var rsa=new pidCrypt.RSA();

var asn=pidCrypt.ASN1.decode(pidCryptUtil.toByteArray(key));
var tree=asn.toHexTree();
rsa.setPublicKeyFromASN(tree);

var strHexSensitiveDataEncrypted=rsa.encrypt("4111111111111111");

var strBase64SensitiveDataEncrypted=pidCryptUtil.fragment(pidCryptUtil.encodeBase64(pidCryptUtil.convertFromHex(strHexSensitiveDataEncrypted)), 64))

console.log(strBase64SensitiveDataEncrypted);

.

phpseclib decryption

require_once("Crypt/RSA.php");

function decrypt($strBase64CipherText)
{
    //CRYPT_RSA_MODE_INTERNAL is slow
    //CRYPT_RSA_MODE_OPENSSL is fast, but requires openssl to be installed, configured and accessible.
    define("CRYPT_RSA_MODE", CRYPT_RSA_MODE_INTERNAL);

    $rsa=new Crypt_RSA();


    //$strPrivateKey=file_get_contents("private.pem");
    //This private key is for example purposes
    //DO NOT REUSE
    $strPrivateKey="-----BEGIN RSA PRIVATE KEY-----
        MIICXQIBAAKBgQDBNHK7R2CCYGqljipbPoj3Pwyz4cF4bL5rsm1t8S30gbEbMnKn
        1gpzteoPlKp7qp0TnsgKab13Fo1d+Yy8u3m7JUd/sBrUa9knY6dpreZ9VTNul8Bs
        p2LNnAXOIA5xwT10PU4uoWOo1v/wn8eMeBS7QsDFOzIm+dptHYorB3DOUQIDAQAB
        AoGBAKgwGyxy702v10b1omO55YuupEU3Yq+NopqoQeCyUnoGKIHvgaYfiwu9sdsM
        ZPiwxnqc/7Eo6Zlw1XGYWu61GTrOC8MqJKswJvzZ0LrO3oEb8IYRaPxvuRn3rrUz
        K7WnPJyQ2FPL+/D81NK6SH1eHZjemb1jV9d8uGb7ifvha5j9AkEA+4/dZV+dZebL
        dRKtyHLfbXaUhJcNmM+04hqN1DUhdLAfnFthoiSDw3i1EFixvPSiBfwuWC6h9mtL
        CeKgySaOkwJBAMSdBhn3C8NHhsJA8ihQbsPa6DyeZN+oitiU33HfuggO3SVIBN/7
        HmnuLibqdxpnDOtJT+9A+1D29TkNENlTWgsCQGjVIC8xtFcV4e2s1gz1ihSE2QmU
        JU9sJ3YeGMK5TXLiPpobHsnCK8LW16WzQIZ879RMrkeDT21wcvnwno6U6c8CQQCl
        dsiVvXUmyOE+Rc4F43r0VRwxN9QI7hy7nL5XZUN4WJoAMBX6Maos2Af7NEM78xHK
        SY59+aAHSW6irr5JR351AkBA+o7OZzHIhvJfaZLUSwTPsRhkdE9mx44rEjXoJsaT
        e8DYZKr84Cbm+OSmlApt/4d6M4YA581Os1eC8kopewpy
        -----END RSA PRIVATE KEY-----
    ";
    $strPrivateKey=preg_replace("/[ \t]/", "", $strPrivateKey);//this won't be necessary when loading from PEM


    $rsa->loadKey($strPrivateKey);

    $binaryCiphertext=base64_decode($strBase64CipherText);

    $rsa->setEncryptionMode(CRYPT_RSA_ENCRYPTION_PKCS1);
    $strBase64DecryptedData=$rsa->decrypt($binaryCiphertext);

    return base64_decode($strBase64DecryptedData);
}

//The pidCrypt example implementation will output a base64 string of an encrypted base64 string which contains the original data, like this one:
$strBase64CipherText="JDlK7L/nGodDJodhCj4uMw0/LW329HhO2EvxNXNUuhe+C/PFcJBE7Gp5GWZ835fNekJDbotsUFpLvP187AFAcNEfP7VAH1xLhhlB2a9Uj/z4Hulr4E2EPs6XgvmLBS3MwiHALX2fES5hSKY/sfSUssRH10nBHHO9wBLHw5mRaeg=";

$binaryDecrypted=decrypt($strBase64CipherText);

//should output '4111111111111111'
var_export($binaryDecrypted);