Use any Random Function in anchor lang

Question

Rand lib is supported in rust but not supported in anchor lang. I want to generate a random number lets say between a range of 0-10. Is there is a way I can do in anchor lang. Or alternatively, if there is a way I could use candy machine random NFT functionality with url as I want to use random numbers to be passed in url.

Code snippet:

 let random_number = 0; // this is supposed to be a random number let say b/w [0-10]
 let path = "http://abc.com";
 let new_uri = format!("{}{}{}", path, random_number, ".json");

            invoke(
                &create_metadata_accounts_v2(
                    ctx.accounts.token_metadata_program.key(),
                    ctx.accounts.metadata.key(),
                    ctx.accounts.mint.key(),
                    ctx.accounts.mint_authority.key(),
                    ctx.accounts.payer.key(),
                    ctx.accounts.payer.key(),
                    num_title,
                    symbol,
                    new_uri,
                    Some(creator),
                    1,
                    true,
                    false,
                    None,
                    None,
                ),
                account_info.as_slice(),
            )?;

Answer 1

As defined here you can’t use random either in Rust or in Anchor if you want to generate a random number either you create your own number or you can use an oracle like a switchboard for generating a random value.

• If you write your own random function using recent blockhash or timestamps available in the program it's most likely to be exploited.
• So it's better to use an oracle for generating the random number. Verifiable Randomness On-chain

References

• Switchboard VRF Demo
• Utilize Switchboard's verifiable randomness to simulate a heads or tails coin toss.
• Live demo of Heads or tails coin toss.

Answer 2

Found a way that we can simply use timestamps for this.

   let clock = Clock::get()?;
   let clock = clock.unix_timestamp % 10; // any number between range 0-10 

Just make sure the random number range is not too large else you may run out of compute units. In case of a very large range of numbers, you can make this implementation on the admin panel where only a transaction signed by admin wallet can call this function (if security is important).