Working with Pubkeys & Accounts

Pubkey identifies accounts and programs. AccountInfo is the runtime handle for lamports, data, owner, and signer flags. Correct slicing and validation prevent privilege escalation.

Recipe

use solana_program::{account_info::AccountInfo, pubkey::Pubkey};
 
fn assert_signer(ai: &AccountInfo) -> ProgramResult {
    if !ai.is_signer { return Err(ProgramError::MissingRequiredSignature); }
    Ok(())
}

When to reach for this:

• Validating client-supplied account lists in native programs.
• Comparing owners, PDAs, and program IDs.
• Iterating accounts with next_account_info.

Working Example

use solana_program::{
    account_info::{next_account_info, AccountInfo},
    program_error::ProgramError,
    pubkey::Pubkey,
};
 
pub fn process_transfer(accounts: &[AccountInfo], expected_owner: &Pubkey) -> ProgramResult {
    let iter = &mut accounts.iter();
    let payer = next_account_info(iter)?;
    let vault = next_account_info(iter)?;
 
    if !payer.is_signer {
        return Err(ProgramError::MissingRequiredSignature);
    }
    if vault.owner != expected_owner {
        return Err(ProgramError::IncorrectProgramId);
    }
    if !vault.is_writable {
        return Err(ProgramError::InvalidAccountData);
    }
    Ok(())
}

What this demonstrates:

• Signer and writable flags are enforced explicitly.
• Owner check binds the vault to your program.
• next_account_info advances the account iterator in client order.

Deep Dive

AccountInfo Fields

Pubkey Tips

• Compare with == on references.
• PDAs have is_on_curve == false off-chain; on-chain treat as normal keys.

Rust Notes

let (pda, bump) = Pubkey::find_program_address(&[b"vault", owner.as_ref()], program_id);

Gotchas

• Account order drift - Client reordering passes wrong account to check.. Fix: Document fixed order; use Anchor constraints or explicit indices.
• Unchecked PDA - Derive bump on-chain and compare to stored canonical bump.. Fix: See Canonical Bumps page.
• Duplicate accounts - Same key passed twice can bypass debit/credit checks.. Fix: Reject duplicate keys in sensitive instructions.
• Owner vs key - Checking key when you meant owner allows impersonation.. Fix: Name variables clearly and lint reviews.
• Lamports mut without signer - Debiting SOL requires signer or PDA authority.. Fix: Validate signer before **lamports changes.

Alternatives

FAQs

Related

• Manual Account Validation - Full checklist
• Deriving PDAs - PDA addresses
• PDA Basics - Why PDAs exist

Stack versions: This page was written for Agave 4.1.1, Solana CLI 3.0.10, Anchor 0.32.1, anchor-lang 0.32.1, Rust 1.91.1, @solana/kit 7.0.0, Surfpool 0.12.0, and LiteSVM 0.6.x.