diff --git a/lib/commands/block.js b/lib/commands/block.js
index 947740908..ea6a19dc2 100644
--- a/lib/commands/block.js
+++ b/lib/commands/block.js
@@ -27,7 +27,7 @@ const BlockStore = require("../storage/block");
     author of the block, since we assume that the block will have been
     encrypted with xsalsa20-poly1305 which is authenticated.
 */
-var validateLoginBlock = function (Env, publicKey, signature, block, _cb) { // FIXME BLOCKS
+Block.validateLoginBlock = function (Env, publicKey, signature, block, _cb) {
     var cb = Util.once(Util.mkAsync(_cb));
 
     // convert the public key to a Uint8Array and validate it
@@ -67,7 +67,7 @@ var validateLoginBlock = function (Env, publicKey, signature, block, _cb) { // F
     // call back with (err) if unsuccessful
     if (!verified) { return void cb("E_COULD_NOT_VERIFY"); }
 
-    return void cb(null, u8_block);
+    return void cb(null, block);
 };
 
 Block.validateAncestorProof = function (Env, proof, _cb) {
@@ -135,20 +135,26 @@ Block.writeLoginBlock = function (Env, safeKey, msg, _cb) {
             previousKey = provenKey;
         }));
     }).nThen(function (w) {
-        validateLoginBlock(Env, publicKey, signature, block, w(function (e, _validatedBlock) {
+        Env.validateLoginBlock(publicKey, signature, block, w(function (e, _validatedBlock) {
             if (e) {
                 w.abort();
                 return void cb(e);
             }
-            if (!(_validatedBlock instanceof Uint8Array)) {
+            if (typeof(_validatedBlock) !== 'string') {
                 w.abort();
-                return void cb('E_INVALID_BLOCK');
+                return void cb('E_INVALID_BLOCK_RETURNED');
             }
 
             validatedBlock = _validatedBlock;
         }));
     }).nThen(function () {
-        BlockStore.write(Env, publicKey, Buffer.from(validatedBlock), function (err) {
+        var buffer;
+        try {
+            buffer = Buffer.from(Nacl.util.decodeBase64(validatedBlock));
+        } catch (err) {
+            return void cb('E_BLOCK_DESERIALIZATION');
+        }
+        BlockStore.write(Env, publicKey, buffer, function (err) {
             Env.Log.info('BLOCK_WRITE_BY_OWNER', {
                 safeKey: safeKey,
                 blockId: publicKey,
@@ -185,7 +191,7 @@ Block.removeLoginBlock = function (Env, safeKey, msg, _cb) {
             return void cb("INCORRECT_KEY");
         }
     }).nThen(function () {
-        validateLoginBlock(Env, publicKey, signature, DELETE_BLOCK, function (e /*::, validatedBlock */) {
+        Env.validateLoginBlock(publicKey, signature, DELETE_BLOCK, function (e) {
             if (e) { return void cb(e); }
             BlockStore.archive(Env, publicKey, function (err) {
                 Env.Log.info('ARCHIVAL_BLOCK_BY_OWNER_RPC', {
diff --git a/lib/workers/db-worker.js b/lib/workers/db-worker.js
index 137b756b4..2371240ec 100644
--- a/lib/workers/db-worker.js
+++ b/lib/workers/db-worker.js
@@ -697,6 +697,10 @@ COMMANDS.VALIDATE_ANCESTOR_PROOF = function (data, cb) {
     Block.validateAncestorProof(Env, data && data.proof, cb);
 };
 
+COMMANDS.VALIDATE_LOGIN_BLOCK = function (data, cb) {
+    Block.validateLoginBlock(Env, data.publicKey, data.signature, data.block, cb);
+};
+
 process.on('message', function (data) {
     if (!data || !data.txid || !data.pid) {
         return void process.send({
diff --git a/lib/workers/index.js b/lib/workers/index.js
index 85c66eeb5..c2bfb5740 100644
--- a/lib/workers/index.js
+++ b/lib/workers/index.js
@@ -451,6 +451,15 @@ Workers.initialize = function (Env, config, _cb) {
             }, cb);
         };
 
+        Env.validateLoginBlock = function (publicKey, signature, block, cb) {
+            sendCommand({
+                command: 'VALIDATE_LOGIN_BLOCK',
+                publicKey: publicKey,
+                signature: signature,
+                block: block,
+            }, cb);
+        };
+
         cb(void 0);
     });
 };