> ## Documentation Index
> Fetch the complete documentation index at: https://cosmos-docs-cosmjs-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Bech32 Addresses

> How Cosmos addresses are encoded and derived from public keys

Cosmos uses [Bech32](https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki)
encoding for all addresses. A Bech32 address has two parts: a human-readable
prefix (HRP) that identifies the chain, and a data section containing the raw
address bytes with a checksum.

```text theme={"system"}
cosmos1qypqxpq9qcrsszg2pvxq6rs0zqg3yyc5lzv7xu
 ^                    ^
 |                    +-- data + checksum (base32 encoded)
 +-- prefix (HRP)
```

## Common Prefixes

| Chain            | Address prefix | Validator prefix |
| ---------------- | -------------- | ---------------- |
| Cosmos Hub       | `cosmos`       | `cosmosvaloper`  |
| Osmosis          | `osmo`         | `osmovaloper`    |
| Juno             | `juno`         | `junovaloper`    |
| Neutron          | `neutron`      | `neutronvaloper` |
| CosmWasm testnet | `wasm`         | `wasmvaloper`    |

## Encoding and Decoding

`@cosmjs/encoding` provides three functions:

```typescript theme={"system"}
import { toBech32, fromBech32, normalizeBech32 } from "@cosmjs/encoding";

const address = toBech32("cosmos", rawAddressBytes);
// "cosmos1..."

const { prefix, data } = fromBech32("cosmos1qypq...");
// prefix: "cosmos", data: Uint8Array (20 bytes)

const normalized = normalizeBech32("COSMOS1QYPQ...");
// "cosmos1qypq..." (lowercased and validated)
```

`fromBech32` validates the checksum and throws on invalid input.
`normalizeBech32` round-trips through decode/encode, which is safer than calling
`toLowerCase()` directly.

## How Addresses Are Derived from Public Keys

The raw 20-byte address inside a Bech32 string is derived from the public key
through hashing. The algorithm depends on the key type:

| Key type           | Derivation                                     |
| ------------------ | ---------------------------------------------- |
| **secp256k1**      | `ripemd160(sha256(compressedPubkey))`          |
| **ed25519**        | `sha256(pubkey).slice(0, 20)`                  |
| **eth\_secp256k1** | `keccak256(uncompressedPubkey[1:]).slice(-20)` |
| **multisig**       | `sha256(aminoEncodedPubkey).slice(0, 20)`      |

The `@cosmjs/amino` package provides `pubkeyToAddress` for this:

```typescript theme={"system"}
import { pubkeyToAddress } from "@cosmjs/amino";

const address = pubkeyToAddress(pubkey, "cosmos");
```

This means the same key pair produces different addresses on different chains —
only the Bech32 prefix changes, but the raw bytes are identical:

```typescript theme={"system"}
const cosmosAddr = toBech32("cosmos", rawAddress); // cosmos1abc...
const osmoAddr = toBech32("osmo", rawAddress);     // osmo1abc...
```