* **[peer](https://github.com/tendermint/tendermint/blob/master/peer):** P2P networking stack. Designed to be extensible.
* **[merkle](https://github.com/tendermint/tendermint/blob/master/merkle):** Immutable Persistent Merkle-ized AVL+ Tree, used primarily for keeping track of mutable state like account balances.
* **[crypto](https://github.com/tendermint/tendermint/blob/master/crypto):** Includes cgo bindings of ed25519.