PHP: PKI encryption tutorial

Solution

1. Generate a self-signed certificate issuing the following command in a linux terminal:
   
   openssl req -x509 -days 730 -newkey rsa:2048 -keyout privateKey.pem -nodes -out certificate.pem
   
2. Place both files privateKey.pem and certificate.pem in the root of your webserver (docroot)
3. Enable PHP OpenSSL extension
4. Create the following PHP file
   

$sensitiveData = 'text to cypher';

echo 'Sensitive data is: ' . $sensitiveData . '
';

//load certificate containing public key for encryption

$pubKey = openssl_pkey_get_public('file:///certificate.pem');

openssl_public_encrypt($sensitiveData, $encryptedData, $pubKey);

echo 'Encrypted data is: ' . $encryptedData . '
';

//load private key for decryption

$privateKey = openssl_pkey_get_private('file:///privateKey.pem');

openssl_private_decrypt($encryptedData, $sensitiveData, $privateKey);

echo 'Sensitive decrypted data is: ' . $sensitiveData . '
';

?>

You should now see an output similar to the following:

Sensitive data is: text to cypher
Encrypted data is: 2äÙdÆÁÕYÄ:6È
Ónñ¬þ–ëëZW »†vÑÜùǤ¿9›øÞr[ÃâÐ$Z„Ÿ–NžRõÜBTåIùr]»o£¹ÉYr<ËúètÊÿøjÀîFÒSyýAáy@5'ÝËð(’;×3µ 9f
aH<ê¼ì/‰cê
¶«¶§)qÊóú|ì³Ö^Š,ùø[-ö¢§idÕ_=d·}ò°xÄŽŽæ1±† è O ÉÀZQìùx|WÀ0 î9QÍ‚aÉIÑ e³]/v‹/5¬÷È€NrL{–=…0µ–Æ+KÈ;ÙthÛä}Lö¼ÖB“ß<ßÝ(ÁÁ0-”
Sensitive decrypted data is: text to cypher

Java: call parent method from overriden method

If you are coding method: "myOverridenMethod()" and want to call it's parent implementation.

Solution:

1. Insert the following line: super.myOverridenMethod()

IntelliJ IDEA: the maximum heap size (-Xmx) might be too large

If you happen to start IntelliJ IDEA, and you see a message box stating the following:

"the maximum heap size (-Xmx) might be too large"

Solution:

1. Go to IntelliJ IDEA instalation dir\bin (in my case: C:\Program Files (x86)\JetBrains\IntelliJ IDEA 10.5\bin)
2. Open and Edit the file: idea.exe.vmoptions
3. Lower the value of the entry: -Xmx2048m  (in my case i lowered the value to : -Xmx1024m)