diff --git a/crypto/symm.rs b/crypto/symm.rs
index fa68c116..63737c70 100644
--- a/crypto/symm.rs
+++ b/crypto/symm.rs
@@ -101,7 +101,7 @@ impl Crypter {
     /**
      * Initializes this crypter.
      */
-    pub fn init(&self, mode: Mode, key: &[u8], iv: &[u8]) {
+    pub fn init(&self, mode: Mode, key: &[u8], iv: Vec<u8>) {
         unsafe {
             let mode = match mode {
                 Encrypt => 1 as c_int,
@@ -171,7 +171,7 @@ impl Drop for Crypter {
  * Encrypts data, using the specified crypter type in encrypt mode with the
  * specified key and iv; returns the resulting (encrypted) data.
  */
-pub fn encrypt(t: Type, key: &[u8], iv: ~[u8], data: &[u8]) -> Vec<u8> {
+pub fn encrypt(t: Type, key: &[u8], iv: Vec<u8>, data: &[u8]) -> Vec<u8> {
     let c = Crypter::new(t);
     c.init(Encrypt, key, iv);
     let r = c.update(data);
@@ -183,7 +183,7 @@ pub fn encrypt(t: Type, key: &[u8], iv: ~[u8], data: &[u8]) -> Vec<u8> {
  * Decrypts data, using the specified crypter type in decrypt mode with the
  * specified key and iv; returns the resulting (decrypted) data.
  */
-pub fn decrypt(t: Type, key: &[u8], iv: ~[u8], data: &[u8]) -> Vec<u8> {
+pub fn decrypt(t: Type, key: &[u8], iv: Vec<u8>, data: &[u8]) -> Vec<u8> {
     let c = Crypter::new(t);
     c.init(Decrypt, key, iv);
     let r = c.update(data);