diff --git a/Cargo.toml b/Cargo.toml
index 57af8f9..a7aef3b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 
 name = "secp256k1"
-version = "0.3.2"
+version = "0.3.3"
 authors = [ "Dawid Ciężarkiewicz <dpc@ucore.info>",
             "Andrew Poelstra <apoelstra@wpsoftware.net>" ]
 license = "CC0-1.0"
diff --git a/src/ffi.rs b/src/ffi.rs
index 7ed3fe4..bd7ed4d 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -19,10 +19,16 @@
 use std::mem;
 use libc::{c_int, c_uchar, c_uint, c_void, size_t};
 
+/// Flag for context to enable no precomputation
+pub const SECP256K1_START_NONE: c_uint = (1 << 0) | 0;
 /// Flag for context to enable verification precomputation
-pub const SECP256K1_START_VERIFY: c_uint = 0x1;
+pub const SECP256K1_START_VERIFY: c_uint = (1 << 0) | (1 << 8);
 /// Flag for context to enable signing precomputation
-pub const SECP256K1_START_SIGN: c_uint = 0x2;
+pub const SECP256K1_START_SIGN: c_uint = (1 << 0) | (1 << 9);
+/// Flag for keys to indicate uncompressed serialization format
+pub const SECP256K1_SER_UNCOMPRESSED: c_uint = (1 << 1) | 0;
+/// Flag for keys to indicate compressed serialization format
+pub const SECP256K1_SER_COMPRESSED: c_uint = (1 << 1) | (1 << 8);
 
 /// A nonce generation function. Ordinary users of the library
 /// never need to see this type; only if you need to control
diff --git a/src/key.rs b/src/key.rs
index 4a2eac1..46672de 100644
--- a/src/key.rs
+++ b/src/key.rs
@@ -160,9 +160,10 @@ impl PublicKey {
 
         unsafe {
             let mut ret_len = ret.len() as ::libc::size_t;
+            let compressed = if compressed { ffi::SECP256K1_SER_COMPRESSED } else { ffi::SECP256K1_SER_UNCOMPRESSED };
             debug_assert!(ffi::secp256k1_ec_pubkey_serialize(secp.ctx, ret.as_ptr(),
                                                              &mut ret_len, self.as_ptr(),
-                                                             if compressed {1} else {0}) == 1);
+                                                             compressed) == 1);
             ret.set_len(ret_len as usize);
         }
         ret
diff --git a/src/lib.rs b/src/lib.rs
index 459e3ca..a197fb5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -356,7 +356,7 @@ impl Secp256k1 {
     /// Creates a new Secp256k1 context with the specified capabilities
     pub fn with_caps(caps: ContextFlag) -> Secp256k1 {
         let flag = match caps {
-            ContextFlag::None => 0,
+            ContextFlag::None => ffi::SECP256K1_START_NONE,
             ContextFlag::SignOnly => ffi::SECP256K1_START_SIGN,
             ContextFlag::VerifyOnly => ffi::SECP256K1_START_VERIFY,
             ContextFlag::Full => ffi::SECP256K1_START_SIGN | ffi::SECP256K1_START_VERIFY