diff --git a/Cargo.lock b/Cargo.lock
index 8f6ccf6a8..daa8da209 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,4 +1,66 @@
 [root]
 name = "ethcore-util"
 version = "0.1.0"
+dependencies = [
+ "env_logger 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "aho-corasick"
+version = "0.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "memchr 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "env_logger"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.41 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "libc"
+version = "0.1.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "libc"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "log"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "memchr"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex"
+version = "0.1.41"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memchr 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
 
diff --git a/src/bytes.rs b/src/bytes.rs
new file mode 100644
index 000000000..06735995f
--- /dev/null
+++ b/src/bytes.rs
@@ -0,0 +1,151 @@
+//! To/From Bytes conversation for basic types
+//!
+//! Types implementing `ToBytes` and `FromBytes` traits
+//! can be easily converted to and from bytes
+//! 
+//! # Examples
+//!
+
+use std::fmt;
+use std::error::Error as StdError;
+
+/// TODO: optimise some conversations
+pub trait ToBytes {
+    fn to_bytes(&self) -> Vec<u8>;
+    fn to_bytes_len(&self) -> usize { self.to_bytes().len() }
+    fn first_byte(&self) -> Option<u8> { self.to_bytes().first().map(|&x| { x })}
+}
+
+impl <'a> ToBytes for &'a str {
+    fn to_bytes(&self) -> Vec<u8> {
+        From::from(*self)
+    }
+    
+    fn to_bytes_len(&self) -> usize { self.len() }
+}
+
+impl ToBytes for String {
+    fn to_bytes(&self) -> Vec<u8> {
+        let s: &str = self.as_ref();
+        From::from(s)
+    }
+    
+    fn to_bytes_len(&self) -> usize { self.len() }
+}
+
+impl ToBytes for u8 {
+    fn to_bytes(&self) -> Vec<u8> {
+        match *self {
+            0 => vec![],
+            _ => vec![*self]
+        }
+    }
+
+    fn to_bytes_len(&self) -> usize {
+        match *self {
+            0 => 0,
+            _ => 1
+        }
+    }
+    fn first_byte(&self) -> Option<u8> { 
+        match *self {
+            0 => None,
+            _ => Some(*self) 
+        }
+    }
+}
+
+impl ToBytes for u64 {
+    fn to_bytes(&self) -> Vec<u8> {
+        let mut res= vec![];
+        let count = self.to_bytes_len();
+        for i in 0..count {
+            let j = count - 1 - i;
+            res.push((*self >> (j * 8)) as u8);
+        }
+        res
+    }
+
+    fn to_bytes_len(&self) -> usize { 8 - self.leading_zeros() as usize / 8 }
+}
+
+macro_rules! impl_map_to_bytes {
+    ($from: ident, $to: ty) => {
+        impl ToBytes for $from {
+            fn to_bytes(&self) -> Vec<u8> { (*self as $to).to_bytes() }
+            fn to_bytes_len(&self) -> usize { (*self as $to).to_bytes_len() }
+        }
+    }
+}
+
+impl_map_to_bytes!(usize, u64);
+impl_map_to_bytes!(u16, u64);
+impl_map_to_bytes!(u32, u64);
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum FromBytesError {
+    UnexpectedEnd
+}
+
+impl StdError for FromBytesError {
+    fn description(&self) -> &str { "from_bytes error" }
+}
+
+impl fmt::Display for FromBytesError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self, f)
+    }
+}
+
+pub type FromBytesResult<T> = Result<T, FromBytesError>;
+
+/// implements "Sized", so the compiler can deducate the size
+/// of the return type
+pub trait FromBytes: Sized {
+    fn from_bytes(bytes: &[u8]) -> FromBytesResult<Self>;
+}
+
+impl FromBytes for String {
+    fn from_bytes(bytes: &[u8]) -> FromBytesResult<String> {
+        Ok(::std::str::from_utf8(bytes).unwrap().to_string())
+    }
+}
+
+impl FromBytes for u8 {
+    fn from_bytes(bytes: &[u8]) -> FromBytesResult<u8> {
+        match bytes.len() {
+            0 => Ok(0),
+            _ => Ok(bytes[0])
+        }
+    }
+}
+
+impl FromBytes for u64 {
+    fn from_bytes(bytes: &[u8]) -> FromBytesResult<u64> {
+        match bytes.len() {
+            0 => Ok(0),
+            l => {
+                let mut res = 0u64;
+                for i in 0..l {
+                    let shift = (l - 1 - i) * 8;
+                    res = res + ((bytes[i] as u64) << shift);
+                }
+                Ok(res)
+            }
+        }
+    }
+}
+
+macro_rules! impl_map_from_bytes {
+    ($from: ident, $to: ident) => {
+        impl FromBytes for $from {
+            fn from_bytes(bytes: &[u8]) -> FromBytesResult<$from> {
+                $to::from_bytes(bytes).map(| x | { x as $from })
+            }
+        }
+    }
+}
+
+impl_map_from_bytes!(usize, u64);
+impl_map_from_bytes!(u16, u64);
+impl_map_from_bytes!(u32, u64);
diff --git a/src/lib.rs b/src/lib.rs
index a93251b65..17262b3ad 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,6 @@
+pub mod bytes;
+pub mod rlp;
+
 #[test]
 fn it_works() {
 }
diff --git a/src/rlp.rs b/src/rlp.rs
new file mode 100644
index 000000000..20acb8e5f
--- /dev/null
+++ b/src/rlp.rs
@@ -0,0 +1,254 @@
+//! Rlp serialization module
+
+use std::fmt;
+use std::cell::Cell;
+use std::error::Error as StdError;
+use bytes::{FromBytes, FromBytesError};
+
+/// rlp container
+#[derive(Debug)]
+pub struct Rlp<'a>{
+    bytes: &'a [u8],
+    cache: Cell<OffsetCache>
+}
+
+/// rlp offset
+#[derive(Copy, Clone, Debug)]
+struct OffsetCache {
+    index: usize,
+    offset: usize
+}
+
+impl OffsetCache {
+    fn new(index: usize, offset: usize) -> OffsetCache {
+        OffsetCache { index: index, offset: offset }
+    }
+}
+
+/// stores basic information about item
+struct ItemInfo {
+    prefix_len: usize,
+    value_len: usize
+}
+
+impl ItemInfo {
+    fn new(prefix_len: usize, value_len: usize) -> ItemInfo {
+        ItemInfo { prefix_len: prefix_len, value_len: value_len }
+    }
+}
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum DecoderError {
+    FromBytesError(FromBytesError),
+    RlpIsTooShort,
+    RlpIsNotArray,
+    BadRlp,
+}
+impl StdError for DecoderError {
+    fn description(&self) -> &str { "builder error" }
+}
+
+impl fmt::Display for DecoderError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self, f)
+    }
+}
+
+impl From<FromBytesError> for DecoderError {
+    fn from(err: FromBytesError) -> DecoderError { DecoderError::FromBytesError(err) }
+}
+
+impl <'a>Rlp<'a> {
+    /// returns new instance of `Rlp`
+    pub fn new(bytes: &'a[u8]) -> Rlp<'a> { 
+        Rlp { 
+            bytes: bytes,
+            cache: Cell::new(OffsetCache::new(usize::max_value(), 0))
+        }
+    }
+
+    /// get container subset at given index
+    ///
+    /// paren container caches searched position
+    pub fn at(&self, index: usize) -> Result<Rlp<'a>, DecoderError> {
+        if !self.is_array() {
+            return Err(DecoderError::RlpIsNotArray);
+        }
+
+        // move to cached position if it's index is less or equal to
+        // current search index, otherwise move to beginning of array
+        let c = self.cache.get();
+        let (mut bytes, to_skip) = match c.index <= index {
+            true => (try!(Rlp::consume(self.bytes, c.offset)), index - c.index),
+            false => (try!(self.consume_array_prefix()), index)
+        };
+
+        // skip up to x items
+        bytes = try!(Rlp::consume_items(bytes, to_skip));
+
+        // update the cache
+        self.cache.set(OffsetCache::new(index, self.bytes.len() - bytes.len()));
+
+        // construct new rlp
+        let found = try!(Rlp::item_info(bytes));
+        Ok(Rlp::new(&bytes[0..found.prefix_len + found.value_len]))
+    }
+
+    /// returns true if rlp is an array
+    pub fn is_array(&self) -> bool {
+        self.bytes.len() > 0 && self.bytes[0] >= 0xc0
+    }
+
+    /// returns true if rlp is a value
+    pub fn is_value(&self) -> bool {
+        self.bytes.len() > 0 && self.bytes[0] <= 0xbf
+    }
+
+    /// returns rlp iterator
+    pub fn iter(&'a self) -> RlpIterator<'a> {
+        self.into_iter()
+    }
+
+    /// consumes first found prefix
+    fn consume_array_prefix(&self) -> Result<&'a [u8], DecoderError> {
+        let item = try!(Rlp::item_info(self.bytes));
+        let bytes = try!(Rlp::consume(self.bytes, item.prefix_len));
+        Ok(bytes)
+    }
+
+    /// consumes fixed number of items
+    fn consume_items(bytes: &'a [u8], items: usize) -> Result<&'a [u8], DecoderError> {
+        let mut result = bytes;
+        for _ in 0..items {
+            let i = try!(Rlp::item_info(result));
+            result = try!(Rlp::consume(result, (i.prefix_len + i.value_len)));
+        }
+        Ok(result)
+    }
+
+    /// return first item info
+    fn item_info(bytes: &[u8]) -> Result<ItemInfo, DecoderError> {
+        let item = match bytes.first().map(|&x| x) {
+            None => return Err(DecoderError::RlpIsTooShort),
+            Some(0...0x7f) => ItemInfo::new(0, 1),
+            Some(l @ 0x80...0xb7) => ItemInfo::new(1, l as usize - 0x80),
+            Some(l @ 0xb8...0xbf) => {
+                let len_of_len = l as usize - 0xb7;
+                let prefix_len = 1 + len_of_len;
+                let value_len = try!(usize::from_bytes(&bytes[1..prefix_len]));
+                ItemInfo::new(prefix_len, value_len)
+            }
+            Some(l @ 0xc0...0xf7) => ItemInfo::new(1, l as usize - 0xc0),
+            Some(l @ 0xf8...0xff) => {
+                let len_of_len = l as usize - 0xf7;
+                let prefix_len = 1 + len_of_len;
+                let value_len = try!(usize::from_bytes(&bytes[1..prefix_len]));
+                ItemInfo::new(prefix_len, value_len)
+            },
+            _ => return Err(DecoderError::BadRlp)
+        };
+
+        match item.prefix_len + item.value_len <= bytes.len() {
+            true => Ok(item),
+            false => Err(DecoderError::RlpIsTooShort)
+        }
+    }
+
+    /// consumes slice prefix of length `len`
+    fn consume(bytes: &'a [u8], len: usize) -> Result<&'a [u8], DecoderError> {
+        match bytes.len() >= len {
+            true => Ok(&bytes[len..]),
+            false => Err(DecoderError::RlpIsTooShort)
+        }
+    }
+}
+
+/// non-consuming rlp iterator
+pub struct RlpIterator<'a> {
+    rlp: &'a Rlp<'a>,
+    index: usize
+}
+
+impl <'a> IntoIterator for &'a Rlp<'a> {
+    type Item = Rlp<'a>;
+    type IntoIter = RlpIterator<'a>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        RlpIterator { rlp: self, index: 0 }
+    }
+}
+
+impl <'a> Iterator for RlpIterator<'a> {
+    type Item = Rlp<'a>;
+
+    fn next(&mut self) -> Option<Rlp<'a>> {
+        let index = self.index;
+        let result = self.rlp.at(index).ok();
+        self.index += 1;
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use rlp;
+    use rlp::Rlp;
+
+    #[test]
+    fn rlp_at() {
+        let data = vec![0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g'];
+        {
+            let rlp = Rlp::new(&data);
+            assert!(rlp.is_array());
+           
+            let cat = rlp.at(0).unwrap();
+            assert!(cat.is_value());
+            assert_eq!(cat.bytes, &[0x83, b'c', b'a', b't']);
+            
+            let dog = rlp.at(1).unwrap();
+            assert!(dog.is_value());
+            assert_eq!(dog.bytes, &[0x83, b'd', b'o', b'g']);
+
+            let cat_again = rlp.at(0).unwrap();
+            assert!(cat_again.is_value());
+            assert_eq!(cat_again.bytes, &[0x83, b'c', b'a', b't']);
+        }
+    }
+
+    #[test]
+    fn rlp_at_err() {
+        let data = vec![0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o'];
+        {
+            let rlp = Rlp::new(&data);
+            assert!(rlp.is_array());
+
+            let cat_err = rlp.at(0).unwrap_err();
+            assert_eq!(cat_err, rlp::DecoderError::RlpIsTooShort);
+
+            let dog_err = rlp.at(1).unwrap_err();
+            assert_eq!(dog_err, rlp::DecoderError::RlpIsTooShort);
+        }
+    }
+
+    #[test]
+    fn rlp_iter() {
+        let data = vec![0xc8, 0x83, b'c', b'a', b't', 0x83, b'd', b'o', b'g'];
+        {
+            let rlp = Rlp::new(&data);
+            let mut iter = rlp.iter();
+
+            let cat = iter.next().unwrap();
+            assert!(cat.is_value());
+            assert_eq!(cat.bytes, &[0x83, b'c', b'a', b't']);
+
+            let dog = iter.next().unwrap();
+            assert!(dog.is_value());
+            assert_eq!(dog.bytes, &[0x83, b'd', b'o', b'g']);
+
+            let cat_again = rlp.at(0).unwrap();
+            assert!(cat_again.is_value());
+            assert_eq!(cat_again.bytes, &[0x83, b'c', b'a', b't']);
+        }
+    }
+}
+