diff --git a/lib/address.js b/lib/address.js
index 5680c63..e5b341e 100644
--- a/lib/address.js
+++ b/lib/address.js
@@ -23,21 +23,14 @@ function Address(opts) {
   if (!(this instanceof Address)) {
     return new Address(opts);
   }
-  opts = opts || {};
-  objectAssign(this, opts);
-  this.version = this.version || 4;
+  opts = objectAssign({}, opts);
+  // Pull out version right away because it may be needed in setters.
+  this.version = popkey(opts, "version") || 4;
   assert(this.version <= 4, "Version too high");
   assert(this.version >= 1, "Version too low");
-  this.stream = this.stream || 1;
-  if (this.ripe) {
-    assertripelen(getripelen(this.ripe), this.version, this.ripe);
-    if (this.ripe.length < 20) {
-      var fullripe = new Buffer(20);
-      fullripe.fill(0);
-      this.ripe.copy(fullripe, 20 - this.ripe.length);
-      this.ripe = fullripe;
-    }
-  }
+  this.stream = popkey(opts, "stream") || 1;
+  // Merge remained values.
+  objectAssign(this, opts);
 }
 
 /**
@@ -80,46 +73,16 @@ function getaddrchecksum(data) {
   return bmcrypto.sha512(bmcrypto.sha512(data)).slice(0, 4);
 }
 
-// Get RIPEMD160(SHA512(SIGN_PUBLIC_KEY || ENC_PUBLIC_KEY)).
-// Arguments could be either private or public keys. Private keys are
-// **always** 32 bytes in length.
-function keys2ripe(signKey, encKey) {
-  var signPublicKey, encPublicKey;
-  if (signKey.length === 32) {
-    signPublicKey = bmcrypto.getPublic(signKey);
-  } else {
-    signPublicKey = signKey;
-  }
-  if (encKey.length === 32) {
-    encPublicKey = bmcrypto.getPublic(encKey);
-  } else {
-    encPublicKey = encKey;
-  }
-  var dataToHash = Buffer.concat([signPublicKey, encPublicKey]);
-  return bmcrypto.ripemd160(bmcrypto.sha512(dataToHash));
-}
-
 /**
  * Calculate the ripe hash of the address.
  * @param {?Object} opts - Options
  * @return {Buffer} Resulting ripe hash.
  */
 Address.prototype.getRipe = function(opts) {
-  var ripe;
   opts = opts || {};
-  if (this.ripe) {
-    ripe = this.ripe;
-  } else {
-    var signKey = this.signPrivateKey || this.signPublicKey;
-    assert(signKey, "No signing key");
-    var encKey = this.encPrivateKey || this.encPublicKey;
-    assert(encKey, "No encryption key");
-    ripe = keys2ripe(signKey, encKey);
-  }
-  var ripelen = getripelen(ripe);
-  assertripelen(ripelen, this.version, ripe);
+  var ripe = this.ripe;
   if (opts.short) {
-    return ripe.slice(20 - ripelen);
+    return ripe.slice(20 - getripelen(ripe));
   } else {
     return ripe;
   }
@@ -231,13 +194,8 @@ Address.fromRandom = function(opts) {
     ripe = bmcrypto.ripemd160(bmcrypto.sha512(keysbuf));
     len = getripelen(ripe);
     if (len <= ripelen && checkripelen(len, version)) {
-      // TODO(Kagami): Do we need to put all these properties or compute
-      // them manually via ECMA5 getters/setters instead?
       opts.signPrivateKey = signPrivateKey;
-      opts.signPublicKey = signPublicKey;
       opts.encPrivateKey = encPrivateKey;
-      opts.encPublicKey = encPublicKey;
-      opts.ripe = ripe;
       return new Address(opts);
     }
   }
@@ -280,13 +238,8 @@ Address.fromPassphrase = function(opts) {
     ripe = bmcrypto.ripemd160(bmcrypto.sha512(keysbuf));
     len = getripelen(ripe);
     if (len <= ripelen && checkripelen(len, version)) {
-      // TODO(Kagami): Do we need to put all these properties or compute
-      // them manually via ECMA5 getters/setters instead?
       opts.signPrivateKey = signPrivateKey;
-      opts.signPublicKey = signPublicKey;
       opts.encPrivateKey = encPrivateKey;
-      opts.encPublicKey = encPublicKey;
-      opts.ripe = ripe;
       return new Address(opts);
     }
     signnonce += 2;
@@ -294,4 +247,81 @@ Address.fromPassphrase = function(opts) {
   }
 };
 
+Object.defineProperty(Address.prototype, "signPrivateKey", {
+  get: function() {
+    return this._signPrivateKey;
+  },
+  set: function(signPrivateKey) {
+    this._signPrivateKey = signPrivateKey;
+    // Invalidate cached values;
+    delete this._signPublicKey;
+    delete this._ripe;
+  },
+});
+
+Object.defineProperty(Address.prototype, "signPublicKey", {
+  get: function() {
+    if (this._signPublicKey) {
+      return this._signPublicKey;
+    } else if (this.signPrivateKey) {
+      this._signPublicKey = bmcrypto.getPublic(this.signPrivateKey);
+      return this._signPublicKey;
+    } else {
+      throw new Error("No signing key");
+    }
+  },
+  set: function(signPublicKey) {
+    this._signPublicKey = signPublicKey;
+  },
+});
+
+Object.defineProperty(Address.prototype, "encPrivateKey", {
+  get: function() {
+    return this._encPrivateKey;
+  },
+  set: function(encPrivateKey) {
+    this._encPrivateKey = encPrivateKey;
+    // Invalidate cached values;
+    delete this._encPublicKey;
+    delete this._ripe;
+  },
+});
+
+Object.defineProperty(Address.prototype, "encPublicKey", {
+  get: function() {
+    if (this._encPublicKey) {
+      return this._encPublicKey;
+    } else if (this.encPrivateKey) {
+      this._encPublicKey = bmcrypto.getPublic(this.encPrivateKey);
+      return this._encPublicKey;
+    } else {
+      throw new Error("No encryption key");
+    }
+  },
+  set: function(encPublicKey) {
+    this._encPublicKey = encPublicKey;
+  },
+});
+
+Object.defineProperty(Address.prototype, "ripe", {
+  get: function() {
+    if (this._ripe) {
+      return this._ripe;
+    }
+    var dataToHash = Buffer.concat([this.signPublicKey, this.encPublicKey]);
+    this._ripe = bmcrypto.ripemd160(bmcrypto.sha512(dataToHash));
+    return this._ripe;
+  },
+  set: function(ripe) {
+    assertripelen(getripelen(ripe), this.version, ripe);
+    if (ripe.length < 20) {
+      var fullripe = new Buffer(20);
+      fullripe.fill(0);
+      ripe.copy(fullripe, 20 - ripe.length);
+      ripe = fullripe;
+    }
+    this._ripe = ripe;
+  },
+});
+
 module.exports = Address;
diff --git a/test.js b/test.js
index 12ffe60..b773d1d 100644
--- a/test.js
+++ b/test.js
@@ -581,6 +581,20 @@ describe("High-level classes", function() {
       expect(Address.decode(addr)).to.equal(addr);
     });
 
+    it("should provide setters for keys and ripe", function() {
+      var addr = Address();
+      expect(function(){addr.ripe}).to.throw(Error);
+      addr.signPrivateKey = Buffer("71c95d26c716a5e85e9af9efe26fb5f744dc98005a13d05d23ee92c77e038d9f", "hex");
+      expect(addr.signPublicKey.toString("hex")).to.equal("042d391543f574608cbcdfd12a37cc4c74dd36e54510b13a6a1d8b7b1498fb96c92873d33ca17586dace7f5ad0f4532a954061ac06bc5230aed9c8374072546571");
+      expect(function(){addr.ripe}).to.throw(Error);
+      addr.encPrivateKey = Buffer("9f9969c93c2d186787a7653f70e49be34c03c4a853e6ad0c867db0946bc433c6", "hex");
+      expect(addr.encPublicKey.toString("hex")).to.equal("04c6ed1b56f2da97fec1b762d43364566faf082c1e4918ae1dbb41757cad41b03b2cc5087f341414e63f6eee72a1fbf0b5f346a1bb3ba944cad204ca597db2bfc8");
+      expect(addr.ripe.toString("hex")).to.equal("003ab6655de4bd8c603eba9b00dd5970725fdd56");
+      expect(addr.getRipe({short: true}).toString("hex")).to.equal("3ab6655de4bd8c603eba9b00dd5970725fdd56");
+      addr.encPrivateKey = Buffer("009969c93c2d186787a7653f70e49be34c03c4a853e6ad0c867db0946bc433c6", "hex");
+      expect(addr.getRipe({short: true}).toString("hex")).to.equal("69617ddb1946dc327cadffcf33889fed587fc1e7");
+    });
+
     // FIXME(Kagami): Don't run it in browser currently because it's
     // very slow. This need to be fixed.
     if (allTests && typeof window === "undefined") {