Email Addresses That Prove You're Not a Bot

// notbot.im — Solana smart contract
use anchor_lang::prelude::*;

#[program]
pub mod notbot_registry {
  pub fn register_address(
    ctx: Context<Register>,
    email: String,
    kyc_proof: [u8; 32],
  ) -> Result<()> {
    let record = &mut ctx.accounts.record;
    require!(!record.is_active, AlreadyRegistered);
    record.owner = ctx.accounts.signer.key();
    record.email = email;
    record.kyc_hash = kyc_proof;
    record.is_active = true;
    record.verified_at = Clock::get()?.unix_timestamp;
    emit!(AddressRegistered {
      owner: record.owner,
      email: record.email.clone(),
    });
    Ok(())
  }
}