In this post, we consider how to quickly determine a type of BTC addresses.

The easiest way to differentiate Bitcoin address types is by looking at their first character or prefix. Almost all standard Bitcoin addresses represent cryptographic hashes, with one notable exception.

Check these address indicators:

• Starts with "1" (Legacy/P2PKH): A hashed address. It encodes the hash of a public key.

• Starts with "3" (P2SH): A hashed script address.

• Starts with "bc1q" (Native SegWit/Bech32): A hashed SegWit public key or script.

• Starts with "bc1p" (Taproot): Non-hashed. Unlike other addresses, Taproot uses the un-hashed raw public key directly, which improves both privacy and multi-signature efficiency.

Why it is important to understand the differences?

Non-hashed addresses are public keys, from which hackers with access to QCs with about 128 logical qubits, can easy reconstruct your private keys and steal your crypto.

Hashed addresses provides some protection against not very powerful QCs, because algorithms to break hashes with QCs are not as efficient as Shor’s type algorithms for reconstruction of private keys from public keys. But such protection exists only, if you did not make any transactions. If you did even a single transaction then your private keys are exposed and you have no protections.

But, even if you did not make any transactions, not post-quantum hashes can be broken with QCs, it only may require more time (weeks or months) to break not post-quantum hashes with QCs, having about 100-1000 logical qubits. The only solution for this case is to use new post-quantum hashes and encryptions algorithms.