diff --git a/src/address.rs b/src/address.rs
deleted file mode 100644
index 5ba93995..00000000
--- a/src/address.rs
+++ /dev/null
@@ -1,19 +0,0 @@
-//! A Bitcoin address, or simply address, is an identifier of 26-35 alphanumeric characters, beginning with the number 1
-//! or 3, that represents a possible destination for a bitcoin payment.
-//!
-//! https://en.bitcoin.it/wiki/Address
-
-/// There are two address formats currently in use.
-/// https://bitcoin.org/en/developer-reference#address-conversion
-pub enum Format {
-	/// Pay to PubKey Hash
-	/// Common P2PKH which begin with the number 1, eg: 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2.
-	/// https://bitcoin.org/en/glossary/p2pkh-address
-	P2PKH,
-	/// Pay to Script Hash
-	/// Newer P2SH type starting with the number 3, eg: 3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy.
-	/// https://bitcoin.org/en/glossary/p2sh-address
-	P2SH,
-}
-
-
diff --git a/src/keys/address.rs b/src/keys/address.rs
new file mode 100644
index 00000000..4c158faf
--- /dev/null
+++ b/src/keys/address.rs
@@ -0,0 +1,71 @@
+//! A Bitcoin address, or simply address, is an identifier of 26-35 alphanumeric characters, beginning with the number 1
+//! or 3, that represents a possible destination for a bitcoin payment.
+//!
+//! https://en.bitcoin.it/wiki/Address
+
+use std::fmt;
+use std::ops::Deref;
+use base58::ToBase58;
+use network::Network;
+use hash::H160;
+use keys::{DisplayLayout, checksum};
+
+/// There are two address formats currently in use.
+/// https://bitcoin.org/en/developer-reference#address-conversion
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub enum Type {
+	/// Pay to PubKey Hash
+	/// Common P2PKH which begin with the number 1, eg: 1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2.
+	/// https://bitcoin.org/en/glossary/p2pkh-address
+	P2PKH,
+	/// Pay to Script Hash
+	/// Newer P2SH type starting with the number 3, eg: 3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy.
+	/// https://bitcoin.org/en/glossary/p2sh-address
+	P2SH,
+}
+
+#[derive(Debug, PartialEq)]
+pub struct Address {
+	/// The type of the address.
+	pub kind: Type,
+	/// The network of the address.
+	pub network: Network,
+	/// Public key hash.
+	pub hash: H160,
+}
+
+pub struct AddressDisplayLayout([u8; 25]);
+
+impl Deref for AddressDisplayLayout {
+	type Target = [u8];
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+impl DisplayLayout for Address {
+	type Target = AddressDisplayLayout;
+
+	fn layout(&self) -> Self::Target {
+		let mut result = [0u8; 25];
+
+		result[0] = match (self.network, self.kind) {
+			(Network::Mainnet, Type::P2PKH) => 0,
+			(Network::Mainnet, Type::P2SH) => 5,
+			(Network::Testnet, Type::P2PKH) => 111,
+			(Network::Testnet, Type::P2SH) => 196,
+		};
+
+		result[1..21].copy_from_slice(&self.hash);
+		let cs = checksum(&result[0..21]);
+		result[21..25].copy_from_slice(&cs);
+		AddressDisplayLayout(result)
+	}
+}
+
+impl fmt::Display for Address {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		self.layout().to_base58().fmt(f)
+	}
+}
diff --git a/src/keys/checksum.rs b/src/keys/checksum.rs
new file mode 100644
index 00000000..931ce1f3
--- /dev/null
+++ b/src/keys/checksum.rs
@@ -0,0 +1,9 @@
+use crypto::dhash;
+
+/// Data checksum
+pub fn checksum(data: &[u8]) -> [u8; 4] {
+	let mut result = [0u8; 4];
+	// TODO: check if this checksum is valid
+	result.copy_from_slice(&dhash(data)[28..]);
+	result
+}
diff --git a/src/keys/display.rs b/src/keys/display.rs
new file mode 100644
index 00000000..c723e37b
--- /dev/null
+++ b/src/keys/display.rs
@@ -0,0 +1,7 @@
+use std::ops::Deref;
+
+pub trait DisplayLayout {
+	type Target: Deref<Target = [u8]>;
+
+	fn layout(&self) -> Self::Target;
+}
diff --git a/src/keys/keypair.rs b/src/keys/keypair.rs
index e7844544..6d75e78a 100644
--- a/src/keys/keypair.rs
+++ b/src/keys/keypair.rs
@@ -1,10 +1,21 @@
+//! Bitcoin KeyPair
+//!
+//! Fields:
+//! - secret - 32 bytes
+//! - public - 65 bytes
+//! - private - secret with additional network identifier (and compressed flag?)
+//! - address_hash - 20 bytes derived from public
+//! - address - address_hash with network identifier and format type
+
 use std::fmt;
 use rustc_serialize::hex::ToHex;
 use rcrypto::sha2::Sha256;
 use rcrypto::ripemd160::Ripemd160;
 use rcrypto::digest::Digest;
 use secp256k1::key;
-use keys::{Secret, Public, Error, SECP256K1, Address};
+use hash::H160;
+use network::Network;
+use keys::{Secret, Public, Error, SECP256K1, Address, Type};
 
 pub struct KeyPair {
 	secret: Secret,
@@ -51,7 +62,7 @@ impl KeyPair {
 		}
 	}
 
-	pub fn address(&self) -> Address {
+	pub fn address_hash(&self) -> H160 {
 		let mut tmp = [0u8; 32];
 		let mut result = [0u8; 20];
 		let mut sha2 = Sha256::new();
@@ -62,12 +73,20 @@ impl KeyPair {
 		rmd.result(&mut result);
 		result
 	}
+
+	pub fn address(&self, network: Network) -> Address {
+		Address {
+			kind: Type::P2PKH,
+			network: network,
+			hash: self.address_hash(),
+		}
+	}
 }
 
 #[cfg(test)]
 mod tests {
 	use super::KeyPair;
-	use base58::{ToBase58, FromBase58};
+	use base58::{FromBase58};
 
 	#[test]
 	fn test_generating_address() {
@@ -78,6 +97,6 @@ mod tests {
 		let mut address = [0u8; 20];
 		address.copy_from_slice(&"16meyfSoQV6twkAAxPe51RtMVz7PGRmWna".from_base58().unwrap()[1..21]);
 		let kp = KeyPair::from_secret(secret).unwrap();
-		assert_eq!(kp.address(), address);
+		assert_eq!(kp.address_hash(), address);
 	}
 }
diff --git a/src/keys/mod.rs b/src/keys/mod.rs
index d3014f3a..5b193541 100644
--- a/src/keys/mod.rs
+++ b/src/keys/mod.rs
@@ -1,13 +1,20 @@
+mod address;
+mod checksum;
+pub mod display;
 pub mod generator;
 pub mod keypair;
 mod error;
+mod private;
 
 use secp256k1;
-use hash::{H160, H256, H520};
+use hash::{H256, H520};
+pub use self::address::{Type, Address};
+pub use self::checksum::checksum;
+pub use self::display::DisplayLayout;
 pub use self::keypair::KeyPair;
 pub use self::error::Error;
+pub use self::private::Private;
 
-pub type Address = H160;
 pub type Secret = H256;
 pub type Public = H520;
 
diff --git a/src/keys/private.rs b/src/keys/private.rs
new file mode 100644
index 00000000..aa2da810
--- /dev/null
+++ b/src/keys/private.rs
@@ -0,0 +1,39 @@
+use std::fmt;
+use base58::ToBase58;
+use network::Network;
+use keys::{Secret, DisplayLayout};
+
+#[derive(Debug, PartialEq)]
+pub struct Private {
+	/// The network on which this key should be used.
+	pub network: Network,
+	/// ECDSA key.
+	pub secret: Secret,
+	/// True if this private key represents a compressed address.
+	pub compressed: bool,
+}
+
+impl DisplayLayout for Private {
+	type Target = Vec<u8>;
+
+	fn layout(&self) -> Self::Target {
+		let mut result = vec![];
+		let network_byte = match self.network {
+			Network::Mainnet => 128,
+			Network::Testnet => 239,
+		};
+
+		result.push(network_byte);
+		result.extend(&self.secret);
+		if self.compressed {
+			result.push(1);
+		}
+		result
+	}
+}
+
+impl fmt::Display for Private {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		self.layout().to_base58().fmt(f)
+	}
+}
diff --git a/src/lib.rs b/src/lib.rs
index cc5b878b..0a5c77e7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,7 +10,6 @@ extern crate secp256k1;
 extern crate base58;
 
 pub mod keys;
-pub mod address;
 pub mod block;
 pub mod block_header;
 pub mod compact_integer;
diff --git a/src/network.rs b/src/network.rs
index 2581768d..27ea105d 100644
--- a/src/network.rs
+++ b/src/network.rs
@@ -5,7 +5,7 @@ const MAGIC_TESTNET: u32 = 0x0709110B;
 
 /// Bitcoin network
 /// https://bitcoin.org/en/glossary/mainnet
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone, Copy)]
 pub enum Network {
 	/// The original and main network for Bitcoin transactions, where satoshis have real economic value.
 	Mainnet,