Question: I have trouble installing my Android SDK on WIndows 7 64bit. I already installed the latest JDK, but for some reason, when the Android SDK installer checks for Java, I get a blank page

![issue](https://i.stack.imgur.com/MLhcZ.png)

I can see that the installer tried something, because another window opened in the taskbar, but it disappeared a second later and I'm left with the above, blank page. All the buttons do not work, so I can't perform the trick I've read in a different topic about press back and next again.

I've got no idea whats going on.

Answer: 
Converting certificates between cer/pem/crt/der/pfx/p12 can be done in Linux with the use of **OpenSSL** tool via the terminal.

These commands allow you to convert certificates and keys to different formats to make them compatible with specific types of servers or software.

**Convert a DER file (.crt .cer .der) to PEM**

> 
> openssl x509 -inform der -in certificate.cer -out certificate.pem
> 
> 
> 

**Convert a PEM file to DER**

> 
> openssl x509 -outform der -in certificate.pem -out certificate.der
> 
> 
> 

**Convert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM**

> 
> openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes
> 
> 
> 

You can add -nocerts to only output the private key or add -nokeys to only output the certificates.

**Convert a PEM certificate file and a private key to PKCS#12 (.pfx .p12)**

> 
> openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt
> 
> 
> 

For more information see:

> 
> <http://www.sslshopper.com/article-most-common-openssl-commands.html>
> 
> 
> <https://support.ssl.com/index.php?/Knowledgebase/Article/View/19>
> 
> 
>
**Convert .crt to .p12** 

openssl pkcs12 -export -out server.p12 -inkey server.key -in server.crt 

Where server.key , is the server key . 
server.crt is cert file from CA or self sigh