key.pem can contain anything - a certificate with a public key, an SSH public key, public key + private key, certificate with a public key + private key. PEM is a text file so you can open it in notepad and check its contents. 

id_rsa is an SSH private key in OpenSSH format. id_rsa.pub is an SSH public key in OpenSSH format. 

.ppk file is Putty&#39;s private key (if memory serves).

To authenticate on remote server you give its admins your public key and use the private key in your SSH client. Alternatively (if admins give you the key pair), you use the private key from that keypair. 

I have an EJB where I am saving an object to the database.  In an example I have seen, once this data is saved (EntityManager.persist) there is a call to EntityManager.flush();  Why do I need to do this?  The object I am saving is not attached and not used later in the method.  In fact, once saved the method returns and I would expect the resources to be released.  (The example code does this on a remove call as well.)

    if (somecondition) {
        entityManager.persist(unAttachedEntity);
    } else {
        attachedEntityObject.setId(unAttachedEntity.getId());
    }
    entityManager.flush();



What does EntityManager.flush do and why do I need to use it?

Can someone show me what i&#39;m doing wrong? I need  my page to refresh after a certain period of time, but it refreshes to the top of the page, I need it to not change the page location!So this is what I have now not working is it the meta tags? Here is what I have no still doesn&#39;t refresh must be doing something wrong?

Here is what I originally had...

    &lt;!DOCTYPE html PUBLIC &quot;-//W3C//DTD HTML 4.01 Transitional//EN&quot;&gt;
    &lt;html&gt;
        &lt;head&gt;
            &lt;meta http-equiv=&quot;refresh&quot; content=&quot;72&quot;&gt;
            &lt;meta http-equiv=&quot;Pragma&quot; CONTENT=&quot;no-cache&quot;&gt;
            &lt;meta http-equiv=&quot;Expires&quot; CONTENT=&quot;-1&quot;&gt;

            &lt;style type=&quot;text/css&quot;&gt;
            body
            { 
                background-image: url(&#39;../Images/Black-BackGround.gif&#39;);
                background-repeat: repeat;
            }
            &lt;/style&gt;
        &lt;/head&gt;

        &lt;script type=&quot;text/javascript&quot;&gt;

        function saveScrollPositions(theForm) {
            if(theForm) {
                var scrolly = typeof window.pageYOffset != &#39;undefined&#39; ? window.pageYOffset
                                                       : document.documentElement.scrollTop;
                var scrollx = typeof window.pageXOffset != &#39;undefined&#39; ? window.pageXOffset
                                                      : document.documentElement.scrollLeft;
                theForm.scrollx.value = scrollx;
                theForm.scrolly.value = scrolly;
            }
        }
        &lt;/script&gt;

     &lt;form action=&quot;enroll.php&quot; name=&quot;enrollment&quot; method=&quot;post&quot; onsubmit=&quot;return saveScrollPositions (this);&quot;&gt;
      &lt;input type=&quot;hidden&quot; name=&quot;scrollx&quot; id=&quot;scrollx&quot; value=&quot;0&quot; /&gt;
      &lt;input type=&quot;hidden&quot; name=&quot;scrolly&quot; id=&quot;scrolly&quot; value=&quot;0&quot; /&gt;

      &lt;STYLE type=&quot;text/css&quot;&gt;
       #Nav a{ position:relative; display:block; text-decoration: none; color:Black; }
       Body td{font-Family: Arial; font-size: 12px; }
      &lt;/style&gt;

After reading some of the initial answers I&#39;ve changed it to this...

    &lt;!DOCTYPE html PUBLIC &quot;-//W3C//DTD HTML 4.01 Transitional//EN&quot;&gt;
    &lt;html&gt;
    &lt;head&gt;

    &lt;style type=&quot;text/css&quot;&gt;
	body
	{ 
		background-image: url(&#39;../Images/Black-BackGround.gif&#39;);
		background-repeat: repeat;
	}
    &lt;/style&gt;
    &lt;/head&gt;


    &lt;script&gt;
    function refreshPage () {
        var page_y = $( document ).scrollTop();
        window.location.href = window.location.href + &#39;?page_y=&#39; + page_y;
    }
    window.onload = function () {
        setTimeout(refreshPage, 35000);
        if ( window.location.href.indexOf(&#39;page_y&#39;) != -1 ) {
            var match = window.location.href.split(&#39;?&#39;)[1].split(&quot;&amp;&quot;)[0].split(&quot;=&quot;);
            $(&#39;html, body&#39;).scrollTop( match[1] );
        }
    }
    &lt;/script&gt;

    &lt;STYLE type=&quot;text/css&quot;&gt;
	#Nav a{ position:relative; display:block; text-decoration: none; color:black; }
	Body td{font-Family: Arial; font-size: 12px; }
    &lt;/style&gt;

Refresh Page and Keep Scroll Position

I am confused between various keys used in encryption.

Amazon gave me `key.pem`

In linux i generate keys like  `id_rsa` and `id_rsa.pub`

Now putty used key like `key.ppk`


I am really confused what type of key is used where

what is the difference between various keys in public key encryption

I am confused between various keys used in encryption.
Amazon gave me <code>key.pem</code>
In linux i generate keys like <code>id_rsa</code> and <code>id_rsa.pub</code>
Now putty used key like <code>key.ppk</code>
I am really confused what type of key is used where

Is it possible to hide/encode/encrypt the php file/source code, and let others have the system installed and run on their machine?

Is it possible to hide/encode/encrypt php source code and let others have the system?

What is the recommended way of generating a secure, random AES key in Java, using the standard JDK?

In other posts, I have found this, but using a `SecretKeyFactory` might be a better idea:

&lt;!-- language: java --&gt;

    KeyGenerator keyGen = KeyGenerator.getInstance(&quot;AES&quot;);
    SecureRandom random = new SecureRandom(); // cryptograph. secure random 
    keyGen.init(random); 
    SecretKey secretKey = keyGen.generateKey();

It would be great if the answer included an explanation of why it is a good way of generating the random key. Thanks!

How to create a secure random AES key in Java?

I&#39;m interested in building a small app for personal use that will encrypt and decrypt information on the client side using JavaScript.  The encrypted information will be stored in a database on a server, but never the decrypted version.

It doesn&#39;t have to be super duper secure, but I would like to use a currently unbroken algorithm.

Ideally I&#39;d be able to do something like

    var gibberish = encrypt(string, salt, key);

to generate the encoded string, and something like

    var sensical = decrypt(gibberish, key);

to decode it later.

So far I&#39;ve seen this:
http://bitwiseshiftleft.github.io/sjcl/

Any other libraries I should look at?

JavaScript string encryption and decryption?

In Main:

    public static void main(String[] args) throws NoSuchAlgorithmException {
        System.out.println(&quot;encrypt:&quot; + encryptPassword(&quot;superuser&quot;)+&quot;:&quot; );
    }
    	
    public static String encryptPassword(final String password) throws NoSuchAlgorithmException {
        MessageDigest md = MessageDigest.getInstance(&quot;MD5&quot;);
        byte[] hashPassword = md.digest(password.getBytes());
        String encryPass = Base64.encodeBase64String(hashPassword);
        return encryPass;
    }

I&#39;m getting this output:

    encrypt:C66i8K4gFQ23j1jN2sRCqQ==:

But when I implemented the same thing in my application I&#39;m getting the output below:

    encrypt:C66i8K4gFQ23j1jN2sRCqQ==
    :

**Note:** new line appending on my encrypted string.
 
application code:

    public boolean authenticateUsernamePasswordInternal(UsernamePasswordCredentials credentials) {
        try {
            System.out.println(&quot;encrypt:&quot; + getHash(&quot;superuser&quot;)+&quot;:&quot; );
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
            throw new BadCredentialsAuthenticationException(ErrorConstants.CONNECTION_FAILED);
        }
    }

    private String getHash(String password) throws NoSuchAlgorithmException, UnsupportedEncodingException{ 	
        MessageDigest md = MessageDigest.getInstance(&quot;MD5&quot;);
        byte[] hashPassword = md.digest(password.getBytes());
        String encryPass = Base64.encodeBase64String(hashPassword);
        return encryPass;
    }

How I can remove that extra new line.
why this is happened, please help me **what is the reason?** 

  [1]: http://i.stack.imgur.com/Gmj35.jpg

new line appending on my encrypted string

I&#39;m studying MD5 encryption, and have found this code using Google:

```
public string CalculateMD5Hash(string input)
{

	// Primeiro passo, calcular o MD5 hash a partir da string
	MD5 md5 = System.Security.Cryptography.MD5.Create();
	byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
	byte[] hash = md5.ComputeHash(inputBytes);

	// Segundo passo, converter o array de bytes em uma string haxadecimal
	StringBuilder sb = new StringBuilder();
	for (int i = 0; i &lt; hash.Length; i++)
	{
		sb.Append(hash[i].ToString(&quot;X2&quot;));
	}
	return sb.ToString();
}
```

Why does it use `ToString(&quot;X2&quot;)`? How is it different from normal `ToString`?

What is the meaning of ToString(&quot;X2&quot;)?

I am running into this error of: 

&lt;!-- language: lang-none --&gt;

    $ git push heroku master
    Warning: Permanently added the RSA host key for IP address &#39;50.19.85.132&#39; to the list of known hosts.
    !  Your key with fingerprint b7:fd:15:25:02:8e:5f:06:4f:1c:af:f3:f0:c3:c2:65 is not authorized to access bitstarter.

I tried to add the keys and I get this error below:

&lt;!-- language: lang-none --&gt;

    $ ssh-add ~/.ssh/id_rsa.pub
    Could not open a connection to your authentication agent.

Could not open a connection to your authentication agent

How do I reattach to a detached mosh session or otherwise get rid of

    Mosh: You have a detached Mosh session on this server (mosh [XXXX]).

i.e. what&#39;s the mosh equivalent of

    screen -D -R
or possibly

    screen -wipe

Furthermore, where can this answer be found in documentation?

How do I reattach to a detached mosh session?

I was trying to setup an SSH connection with Github following this tutorial:

* [Testing your SSH connection](https://docs.github.com/en/github/authenticating-to-github/connecting-to-github-with-ssh/testing-your-ssh-connection)

I came across the following command: 

    $ ssh -T git@github.com 
    # Attempts to ssh to github

Curious, I looked at the ssh manual. It said the following:

     -T      Disable pseudo-tty allocation.

What is tty allocation? What does tty stand for? Why are we disabling it?&lt;br&gt;I earnestly tried to look it up but I was unable to find even a definition.

What is Pseudo TTY-Allocation? (SSH and Github)

I am using git bash. I have to use

    eval `ssh-agent.exe`
    ssh-add /my/ssh/location/
every time when I start a new git bash.

Is there a way to set ssh agent permanently? Or does windows has a good way
to manage the ssh keys?

I&#39;m a new guy, please give me detailed tutorial, thanks!

Running SSH Agent when starting Git Bash on Windows

When I try to push my app to Heroku I get this response:

    fatal: &#39;heroku&#39; does not appear to be a git repository
    fatal: Could not read from remote repository.

    Please make sure you have the correct access rights
    and the repository exists.

I have tried &#39;heroku keys:add&#39; but still comes up with the same result.
I already have an ssh key for my GitHub account.

&#39;heroku&#39; does not appear to be a git repository

I&#39;m looking for some advice or best practice to back up S3 bucket.  
The purpose of backing up data from S3 is to prevent data loss because of the following:  

 1. S3 issue
 2. issue where I accidentally delete this data from S3

After some investigation I see the following options:

 1. Use versioning http://docs.aws.amazon.com/AmazonS3/latest/dev/Versioning.html  
 2. Copy from one S3 bucket to another using AWS SDK
 3. Backup to Amazon Glacier http://aws.amazon.com/en/glacier/
 4. Backup to production server, which is itself backed up

What option should I choose and how safe would it be to store data only on S3? Want to hear your opinions.  
Some useful links:

 - [Data Protection Documentation][1]
 - [Data Protection FAQ][2]

  [1]: http://docs.aws.amazon.com/AmazonS3/latest/dev/DataDurability.html
  [2]: http://aws.amazon.com/s3/faqs/#How_durable_is_Amazon_S3

Backup strategies for AWS S3 bucket

I&#39;m trying to figure it out what can I use for a future project, we plan to store from about 500k records per month in the first year and maybe more for the next years this is a vertical application so there&#39;s no need to use a database for this, that&#39;s the reason why I decided to choose a noSQL data storage.

The first option that came to my mind was mongo db since is a very mature product with a lot of support from the community but in the other hand we got a brand new product that offers a managed service at top performance, I&#39;ll develop this application but there&#39;s no maintenance plan (at least for now) so I think that will be a huge advantage since amazon provides a elastic way to scale.

My major concern is about the query structure, I haven&#39;t looked at the dynamoDB query capabilities yet but since is a k/v data storage I feel that this could be more limited than mongo db.

If someone had the experience of moving a project from mongoDB to DynamoDB, any advice will be totally appreciated.



DynamoDB vs MongoDB NoSQL

I want to use my Amazon ec2 instance but faced the following error: 

    Permission denied (publickey).

I have created my key pair and downloaded **.pem** file.


Given:               

    chmod  600 pem file.

Then, this command

    ssh -i /home/kashif/serverkey.pem  ubuntu@ec2-54-227-242-179.compute-1.amazonaws.com

But have this error:

    Permission denied (publickey)

Also, **how can I connect with filezilla to upload/download files?**

       

Permission denied (publickey) when SSH Access to Amazon EC2 instance

I understand Amazon will charge per GB provisioned EBS storage. If I create AMI of my instance, does this mean my EBS volume will be duplicated, and hence incur additional cost?

Is there other cost charge in creating and storing an AMI (Amazon Machine Image)? 

Cost of storing AMI

I&#39;m using the `aws-sdk-php`, the SesClient specifically, i&#39;ve deployed an app in a customer server (hosted in DreamHost) and I&#39;m getting this error:

    Signature not yet current: 20130909T170846Z is still later than 20130909T170823Z (20130909T170323Z + 5 min.)

I&#39;m guessing the server time is misconfigured, I&#39;m trying to reach DH support to check on that, i bet that will take a while.

Any other ideas? The app has been deployed many times before and i&#39;ve never seen this error.

AWS SDK Error - Signature not yet current

From time to time I have to run a command-line tool (a Python script) whose output seems to break my terminal.
After the execution is finished, the typing feedback is gone (I can&#39;t see what I&#39;m typing), and also line breaks are not displayed. This happens if the terminal is started remotely via `Putty`, and also locally when using `gnome-terminal`.

For example, after the problem happens, if I type &lt;kbd&gt;ENTER&lt;/kbd&gt; `pwd` &lt;kbd&gt;ENTER&lt;/kbd&gt;, I would expect to see:

    [userA@host006 ~]$
    [userA@host006 ~]$ pwd
    /home/userA
    [userA@host006 ~]$

But actually the output is:

    [userA@host006 ~]$ [userA@host006 ~]$ /home/userA
                                                                 [userA@host006 ~]$

The only way to fix it is to close that terminal and start a new one.

Maybe be related: the script output contains some terminal-based formatting (e.g. invert foreground/background to highlight some status messages). If I dump this output to a file I can see things like `[07mSome Message Here[0m`.

Any ideas what I could do to prevent this?

Linux Terminal: typing feedback gone, line breaks not displayed

I&#39;m trying to connect to my Debian Google Compute Engine server through PuTTy (I&#39;ve tried other alternatives too) but when I do I get the error &quot;Disconnected: No supported authentication methods available (server sent: publickey)

![](https://puu.sh/5x8OY/ec3a73a225.png)

The google server came without a username and password, only a url to automatically login to their own terminal.

Google server putty connect &#39;Disconnected: No supported authentication methods available (server sent: publickey)

I created key pair using `puttygen.exe` (client is windows 8). On server (Ubuntu 12.04.3 LTS), I have put my public key in `~/.ssh/authorized_keys`. The public key is this:

    ssh-rsa AAAAB3NzaC1yc2EAAAABJQAAAQEAopfM6RHOgnuc4Aftn3t4k5UIAT3StCAbn/vg/IMbphbXadshC+79sIlRq3P4zGzMjFTP4hKnzu6ehLV5lmj/qorq3SKT+bPO5Qrac3VbIlrGvuBFDDjP82I2Hwg3HzlsFTstqk++KToapaTYZ7jENEYyPl2wnzITJnt//+4U1o6juoXTKgdNE02hHnRZyHOV/bnkZyJJCEwJv5U0eXSThQnhmXtUxGT8U0HQNFiXfqIIVllhWiCnyrhhIaKz/CIJNAd2VmzyJzQtJtTQX8aWSNVrZju6Sv2/RncTNvsACdNgjjh/FH8PQXaep00jlJ3MOdsC8vz6VSPFbh6iKy1oLQ== rsa-key-20131231

So it&#39;s correct (one line, no comments, starts with ssh-rsa, etc.)

`.ssh` dir permission level is 700, authorized_keys file permission is 600. Both directory and file owned by the actual user that I try to log in. 

When I try connecting I&#39;m getting `&#39;server refused our key&#39;` and server asks for password. That&#39;s all. Nothing is logged to `/var/log/auth.log` when attempting to log in with the key. 

I&#39;ve looked everywhere and all articles and tips mention setting chmod 600 and 700 for the file/directory and formatting the key correctly. I&#39;ve done all this still getting &#39;refused our key&#39; error and I&#39;m out of ideas.

Putty: Getting Server refused our key Error

I&#39;m trying to test some C code that I&#39;m writing. The only issue is that the code needs to be executed on a remote machine. 
My laptop is pretty old, and there is no driver for my wireless card available for Ubuntu, so booting into Linux to circumvent this problem isn&#39;t an option. 
Here&#39;s my question: 

I&#39;m using putty to SSH into the remote machine, and I&#39;m writing my code on Notepad++.
The location of my file is:
     `C:\Users\Admin\Desktop\WMU\5260\A2.c`

My problem is that when I use the command `scp C:\Users\Admin\Desktop\WMU\5260\A2.c ~`
I get the error `could not resolve hostname C:. Name or service not known&quot;.`

I&#39;ve also tried `scp Users\Admin\Desktop\WMU\5260\A2.c ~` which gives me the error `Cannot stat &#39;Users\Admin\Desktop\WMU\5260\A2.c&#39;: no such file or directory`

What am I doing incorrectly?



Using putty to scp from windows to Linux

I am using putty to connect a remote host and editing via vim. I meet a trouble when I try to paste something to vim. That&#39;s, I copy something to clipboard in my local host and want to paste it to the vim in the remote host. How to do that?

ps: I am using putty! So, I open a vim window via putty. The very need is that I want to copy something in my local host and paste it to the vim editor opened by putty. That&#39;s all. Thanks!

how to paste to vim when using putty

I am trying to get a better grapple on how public/private keys work. I understand that a sender may add a digital signature to a document using his/her private key to essentially obtain a hash of the document, but what I do not understand is how the public key can be used to verify that signature. 

My understanding was that public keys encrypt, private keys decrypt... can anyone help me understand? 


How does a public key verify a signature?

I have a gpg .key file that is used as passphrase for decrypting a .dat.pgp file. The encrypted .data.pgp file gets successfully decrypted on one server with same .key file using following command

    cat xxx_gpg.key | /usr/bin/gpg --batch --quiet -o xxx.dat --passphrase-fd O -d xxx.dat.pgp

But, when I move same key to another server xxx_gpg.key and run same above command, I get following error - 

    gpg: decryption failed: No secret key


EDIT: 

I find that `gpg --list-secret-keys` returns some data on server where it works but no results are returned for other server.

How can we configure secret key


gpg decryption fails with no secret key error

I&#39;m trying to use interesting password management [tool][1] named Pass.

I did the following:

 1. Installed gpg tool `$ sudo dnf install gpg`
 2. Generated a key using `$ gpg --gen-key` 
 3. Typed `$ pass init &quot;foobar id of my gpg key&quot;` as stated [here][1]
 4. Got
 
`mkdir: created directory ‘/home/chichivica/.password-store/’
 Password store initialized for foobar@email.com`

 5. Tried to add a simple password 

`$ pass insert foo
Enter password for foo: 
Retype password for foo:`

 6. And there is the problem

`gpg: A45A123C: There is no assurance this key belongs to the named user
gpg: [stdin]: encryption failed: Unusable public key`


Could anyone give me some advice?

  [1]: http://www.passwordstore.org/

Content Type	Original Author	Original Content on Stackoverflow
Question	user22	View Question on Stackoverflow
Solution 1 - Encryption	Eugene Mayevski 'Callback	View Answer on Stackoverflow

what is the difference between various keys in public key encryption

Encryption Problem Overview

Encryption Solutions

Solution 1 - Encryption

Refresh Page and Keep Scroll Position

What does EntityManager.flush do and why do I need to use it?

Attributions