diff --git a/node/index.js b/node/index.js
index efb9708..9b8251c 100644
--- a/node/index.js
+++ b/node/index.js
@@ -2,21 +2,10 @@ const ffi = require('ffi');
 const struct = require('ref-struct');
 const ref = require('ref');
 
-
-const libhkana = ffi.Library('libkana_hash', {
-    '_kana_new_salt': ['int', ['pointer', 'long', 'pointer']],
-    '_kana_free_salt': ['int', ['pointer']],
-    '_kana_do': ['int', ['pointer', 'long', 'pointer', 'pointer', 'long']],
-    '_kana_length': ['int', ['pointer', 'long', 'pointer', 'pointer']],
-});
-
 const Kana = require('./kana');
+const Salt = require('./salt');
 
-let buffer= ref.alloc('long');
-let sz = ref.alloc('long');
-console.log(libhkana._kana_length(buffer, 2, null, sz));
-console.log(sz.deref());
+//console.log(new Kana(Kana.CRC64, new Salt("hello lolis")).once("hello worldノチそぬとね"));
 
-let output = new Buffer(sz);
-console.log(libhkana._kana_do(buffer, 2, null, output, sz));
-console.log(ref.readCString(output, 0));
+module.exports.Kana = Kana;
+module.exports.Salt = Salt;
diff --git a/node/kana.js b/node/kana.js
index c4bd002..8d36527 100644
--- a/node/kana.js
+++ b/node/kana.js
@@ -2,9 +2,110 @@ const ffi = require('ffi');
 const struct = require('ref-struct');
 const ref = require('ref');
 
-const Salt = module.exports.Salt = struct({
-    'size': 'pointer',
+const Salt = struct({
+    'type': 'char',
+    'size': 'int',
     'body': 'pointer',
 });
-const PSalt = module.exports.PSalt = ref.refType(Salt);
+const PSalt = ref.refType(Salt);
 
+const Context = struct({
+    'algo': 'char',
+    'salt': Salt,
+});
+const PContext = ref.refType(Context);
+const PLong = ref.refType(ref.types.long);
+
+const lib = ffi.Library('libkhash', {
+    'khash_new_context': ['int', ['char', 'char', 'string', 'long', PContext]],
+    'khash_free_context': ['int', [PContext]],
+    'khash_clone_context': ['int', [PContext, PContext]],
+
+    'khash_length': ['int', [PContext, 'string', 'long', PLong]],
+    'khash_do': ['int', [PContext, 'string', 'long', 'string', 'long']],
+});
+
+const ctx_create = (algo, salt, salt_ref, salt_sz) => {
+    let ctx_ptr = ref.alloc(Context);
+    lib.khash_new_context(algo, salt, salt_ref, salt_sz, ctx_ptr);
+    return ctx_ptr;
+};
+const ctx_free = (ptr) => {
+    lib.khash_free_context(ptr);
+    return ptr.deref();
+};
+const ctx_clone = (src) => {
+    let dst = ref.alloc(Context);
+    lib.khash_clone_context(src,dst);
+    return dst;
+};
+const khash_length = (ctx, jsstring) => {
+    let string = ref.allocCString(jsstring);
+    let len = ref.alloc('long');
+    lib.khash_length(ctx, string, string.length, len);
+    return len.deref();
+};
+const khash_do = (ctx, jsstring, len) => {
+    let string = ref.allocCString(jsstring);
+    let buffer = Buffer.alloc(len+1);
+    lib.khash_do(ctx,string,string.length,buffer,len);
+    return ref.readCString(buffer,0);
+};
+
+const get_salt_type = (salt) => {
+    if (salt && salt.tag) {
+	switch(salt.tag)
+	{
+	    case '__NONE':
+	    return Kana.SALT_NONE;
+	    case '__RANDOM':
+	    return Kana.SALT_RANDOM;
+	    case '__SPECIFIC':
+	    return Kana.SALT_SPECIFIC;
+	    default:
+	    return Kana.SALT_DEFAULT;
+	}
+    }
+    else return Kana.SALT_DEFAULT;
+};
+
+function Kana(algo, salt)
+{
+    const stype = get_salt_type(salt);
+    const fbuffer = salt ? salt.buffer || null : null;
+    this.ctx = ctx_create(algo || 0, stype, fbuffer, fbuffer ? fbuffer.length : 0);
+}
+const K = Kana.prototype;
+
+K.finish = function() {
+    ctx_free(this.ctx);
+};
+
+K.once = function(string) {
+    let len = khash_length(this.ctx, string);
+    return khash_do(this.ctx, string, len);
+};
+
+Kana.ALGO_DEFAULT = 0;
+Kana.ALGO_CRC32 = 1;
+Kana.ALGO_CRC64 = 2;
+Kana.ALGO_SHA256 = 3;
+
+Kana.SALT_NONE = 0;
+Kana.SALT_DEFAULT = 1;
+Kana.SALT_SPECIFIC = 2;
+Kana.SALT_RANDOM = 3;
+
+
+module.exports = Kana;
+/*
+  const Kana = require('./kana');
+
+  let buffer= ref.alloc('long');
+  let sz = ref.alloc('long');
+  console.log(libhkana._kana_length(buffer, 2, null, sz));
+  console.log(sz.deref());
+
+  let output = new Buffer(sz);
+  console.log(libhkana._kana_do(buffer, 2, null, output, sz));
+  console.log(ref.readCString(output, 0));*/
diff --git a/node/salt.js b/node/salt.js
new file mode 100644
index 0000000..9313e44
--- /dev/null
+++ b/node/salt.js
@@ -0,0 +1,17 @@
+const ref = require('ref');
+
+function Salt(buffer, tag)
+{
+    this.tag = tag || '__SPECIFIC';
+    if (buffer) {
+	this.buffer = ref.allocCString(buffer);
+    } else {
+	this.buffer = null;
+    }
+}
+
+Salt.None = new Salt(null, '__NONE');
+Salt.Random = new Salt(null, '__RANDOM');
+Salt.Default = new Salt(null, '__DEFAULT');
+
+module.exports = Salt;