Is the data encrypted with openssl_public_encrypt different every time?

Question

why is the value of $ encrypted differently each time?

// aquire public key from server
$server_public_key = openssl_pkey_get_public(file_get_contents("C:\publickey.pem"));

// rsa encrypt
openssl_public_encrypt("123", $encrypted, $server_public_key);

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also i tried this

$publicKey = "file://C:/publickey.pem";
$privateKey = "file://C:/privatekey.pem";
$plaintext = "String to encrypt";

openssl_public_encrypt($plaintext, $encrypted, $publicKey);
$transfer = base64_encode($encrypted);
openssl_private_decrypt($encrypted, $decrypted, $privateKey);

echo $transfer;  //encrypted string

and $ transfer - each time a different line: ...

Z1xyMUquARxcGjqjjSHNAm41CnHI02GXxLyFivvta8YhDkhRJdD4i3kx + 8GElljdiSY / NMF9UD3ritWMLGmscdq / QyIf + geYxJFePNd1yNj1jbjjjjjjjjjjjjjjj

mRgLPsPtMoV9la7zzuU + cLzS5xMDp7QUmH6Iv4Sv4 / FNjt62zcv9ZMWkfG3uVhS8Z1UDtGl + met1CYjBTcfjHCR6hahbwOkTCICXtkRQcc371vURW04XhQzMNgIIbvN5BBdmIyYI6alrS2vKUq7b3T0h8sJf36zh5CynYzyDCFU =

G5FhMoJGiUwEBvEOeZpDDrEXdxbWX5iaJ6F + VdYJ3CURPRMftskZNlDhat8gA5V0G + 3nXVQZptkHjxMkOqPlmwJHjgIqAiFppHLpEKohyT9qNwkAR00Y6PiWrNUJPiEIZqXHAb8TS0AA0Quhc0UAwcc + I8NGOD59k8BrZE6Z5Ew =

Answer 1

PKCS # 1 , .

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