# HASH160 and RIPEMD-160

HASH160 is SHA-256 followed by RIPEMD-160. It turns a 33-byte public key into the 20-byte hash inside most Bitcoin addresses. See how and why.

Canonical page: https://mybitcoinexplorer.com/learn/hash160-and-ripemd160
Topic: Cryptography
Published: 2026-10-29
Updated: 2026-10-30


## Two hashes in a row
~~~
HASH160(x) = RIPEMD-160( SHA-256(x) )
~~~

> Diagram: From public key to the 20-byte hash in an address — Public key: 33 bytes → SHA-256: 32 bytes → RIPEMD-160: 20 bytes → *Address: encoded

## Why use it?
- **Shorter addresses:** 20 bytes instead of 33, so addresses are easier to share.
- **An extra layer:** until you spend, only the hash of your public key is public, not the key itself.
- **Two different designs:** if one hash function were weakened, the combination would still be hard to attack.

## Where it appears
| Use | Hashed data |
|---|---|
| [Pay to public key hash (P2PKH)](https://mybitcoinexplorer.com/learn/p2pkh) (addresses starting with 1) | the public key |
| [Pay to script hash (P2SH)](https://mybitcoinexplorer.com/learn/p2sh) (addresses starting with 3) | the redeem script |
| P2WPKH (bc1q…, 42 characters) | the public key |

[Taproot](https://mybitcoinexplorer.com/learn/taproot) addresses don't hash the key: they contain a 32-byte tweaked public key directly.


## Spot HASH160 in a script
In a P2PKH locking script, the bytes after `OP_HASH160` are the 20-byte public key hash:

~~~
OP_DUP OP_HASH160 89abcdefabbaabbaabbaabbaabbaabbaabbaabba OP_EQUALVERIFY OP_CHECKSIG
~~~

The address is just that hash with a version byte and checksum, encoded in Base58 or Bech32.

## Why RIPEMD-160?
It was a well-known, independent design from a different team than SHA-256, giving a shorter output. Combining two unrelated hash functions was a cautious choice in 2008.


## Key takeaways

- HASH160 = RIPEMD-160 of SHA-256.
- It produces the 20-byte hash in P2PKH, P2SH and P2WPKH outputs.
- Taproot uses the public key itself instead.

## Common questions

### Is 160 bits secure enough?

For finding a key that matches someone's hash, yes. Collisions are easier at 160 bits, which is one reason newer script outputs like P2WSH use 32-byte SHA-256.

### Why do two addresses from the same key look different?

Different address types encode the hash (or key) differently.

### Is RIPEMD-160 still secure?

For Bitcoin's use (preventing someone from finding a key matching your hash), yes. No practical attack is known.

### Does Taproot use HASH160?

No. Taproot outputs contain a 32-byte tweaked public key directly.

## Related lessons

- [Public keys](https://mybitcoinexplorer.com/learn/public-keys)
- [Bitcoin addresses](https://mybitcoinexplorer.com/learn/bitcoin-addresses)
- [Pay to public key hash (P2PKH)](https://mybitcoinexplorer.com/learn/p2pkh)
- [SHA-256](https://mybitcoinexplorer.com/learn/sha-256)