Program Derived Addresses

Program Derived Addresses (PDAs)

PDAs are one of Solana's most powerful features. They allow programs to deterministically derive addresses and sign transactions without a private key.

How PDAs Work

PDA = findProgramAddress([seed1, seed2, ...], programId)
    = SHA256(seed1 + seed2 + ... + programId + bump) (mod curve order)

The key insight: PDAs are addresses that fall off the Ed25519 curve, meaning no private key exists for them. Only the program itself can sign for its PDAs.

Common PDA Patterns

// User-specific data account
let (pda, bump) = Pubkey::find_program_address(
    &[b"user_data", user.key().as_ref()],
    program_id
);

// Global state (singleton)
let (pda, bump) = Pubkey::find_program_address(
    &[b"global_config"],
    program_id
);

// Escrow between two parties
let (pda, bump) = Pubkey::find_program_address(
    &[b"escrow", maker.key().as_ref(), taker.key().as_ref()],
    program_id
);

PDAs as Signers

When a program uses invoke_signed, it provides the seeds + bump to prove it "owns" the PDA:

invoke_signed(
    &transfer_ix,
    &[pda_account, destination, system_program],
    &[&[b"vault", &[bump_seed]]], // signer seeds
)?;

This is how programs can transfer SOL and tokens from PDA-owned accounts — no private key needed.