PS-9139 Document new PS Encryption UDFs functionality - 8.0

	modified:   docs/encryption-functions.md

Author: patrickbirch

docs/encryption-functions.md

@@ -1,7 +1,24 @@
-# Encryption functions
+# Encryption user-defined functions
 
 Percona Server for MySQL 8.0.28-20 adds encryption functions and variables to manage the encryption range. The functions may take an algorithm argument. Encryption converts plaintext into ciphertext using a key and an encryption algorithm.
 
+## Version updates
+
+Percona Server for MySQL 8.0.40 adds the following:
+
+* Support for `PKCS1 OAEP` padding for RSA encrypt / decrypt operations
+
+??? example "Explanation"
+
+    ```{.text .no-copy}
+    PKCS1 OAEP (Optimal Asymmetric Encryption Padding) is a cryptographic technique used to add randomness to a message before encryption. This randomness helps to increase the security of the encrypted message.
+
+    When you encrypt a message using a public-key encryption algorithm like RSA, the message is first padded with random data. This padded message is then encrypted using the recipient's public key. The recipient can then decrypt the message using their private key.
+
+    OAEP padding adds a layer of security by making it more difficult for attackers to exploit weaknesses in the encryption algorithm or to recover the original message.
+    ```
+
+
 You can also use the user-defined functions with the PEM format keys generated externally by the OpenSSL utility.
 
 A digest uses plaintext and generates a hash value. This hash value can verify if the plaintext is unmodified. You can also sign or verify on digests to ensure that the original plaintext was not modified. You cannot decrypt the original text from the hash value.
@@ -64,7 +81,7 @@ A plaintext as a string.
 
 The following are the function’s parameters:
 
-* algorithm - the encryption algorithm supports RSA to decrypt the string.
+* algorithm - the encryption algorithm supports RSA to decrypt the string. Percona Server for MySQL 8.0.40 added support for PKCS1 OAEP padding for RSA encrypt operations
 
 * key_str - a string in the PEM format. The key string must have the following attributes: