Is it true that if there is Cryptographically secure pseudorandom number generator then there is One-way function?
If you have a really Cryptographically secure pseudorandom number generator you can use it to create a "one time pad" which you can then use to encrypt your message.
One time pad has perfect secrecy (for definition see Shannon or here lecture notes on perfect secrecy).
Your function will be a one way function since only you can invert the coded message to it's original plaintextform.
BUT: to decipher the message you'll still have to send the pad you've used throu a secure channel or encrypt it with some other cryptosystem .