Merge branch 'release-v0.9.0' into releasev0.9.0

1 files changed, 843 insertions, 0 deletions

diff --git a/openssl/src/bn.rs b/openssl/src/bn.rs
new file mode 100644
index 00000000..d52be884
--- /dev/null
+++ b/openssl/src/bn.rs
@@ -0,0 +1,843 @@
+use ffi;
+use libc::c_int;
+use std::cmp::Ordering;
+use std::ffi::CString;
+use std::{fmt, ptr};
+use std::ops::{Add, Div, Mul, Neg, Rem, Shl, Shr, Sub, Deref};
+
+use {cvt, cvt_p, cvt_n};
+use crypto::CryptoString;
+use error::ErrorStack;
+use types::{OpenSslType, OpenSslTypeRef};
+
+/// Options for the most significant bits of a randomly generated `BigNum`.
+pub struct MsbOption(c_int);
+
+/// The most significant bit of the number may be 0.
+pub const MSB_MAYBE_ZERO: MsbOption = MsbOption(-1);
+
+/// The most significant bit of the number must be 1.
+pub const MSB_ONE: MsbOption = MsbOption(0);
+
+/// The most significant two bits of the number must be 1.
+///
+/// The number of bits in the product of two such numbers will always be exactly twice the number
+/// of bits in the original numbers.
+pub const TWO_MSB_ONE: MsbOption = MsbOption(1);
+
+type_!(BigNumContext, BigNumContextRef, ffi::BN_CTX, ffi::BN_CTX_free);
+
+impl BigNumContext {
+    /// Returns a new `BigNumContext`.
+    pub fn new() -> Result<BigNumContext, ErrorStack> {
+        unsafe { cvt_p(ffi::BN_CTX_new()).map(BigNumContext) }
+    }
+}
+
+impl BigNumRef {
+    /// Erases the memory used by this `BigNum`, resetting its value to 0.
+    ///
+    /// This can be used to destroy sensitive data such as keys when they are no longer needed.
+    pub fn clear(&mut self) {
+        unsafe { ffi::BN_clear(self.as_ptr()) }
+    }
+
+    /// Adds a `u32` to `self`.
+    pub fn add_word(&mut self, w: u32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_add_word(self.as_ptr(), w as ffi::BN_ULONG)).map(|_| ()) }
+    }
+
+    /// Subtracts a `u32` from `self`.
+    pub fn sub_word(&mut self, w: u32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_sub_word(self.as_ptr(), w as ffi::BN_ULONG)).map(|_| ()) }
+    }
+
+    /// Multiplies a `u32` by `self`.
+    pub fn mul_word(&mut self, w: u32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_mul_word(self.as_ptr(), w as ffi::BN_ULONG)).map(|_| ()) }
+    }
+
+    /// Divides `self` by a `u32`, returning the remainder.
+    pub fn div_word(&mut self, w: u32) -> Result<u64, ErrorStack> {
+        unsafe {
+            let r = ffi::BN_div_word(self.as_ptr(), w.into());
+            if r == ffi::BN_ULONG::max_value() {
+                Err(ErrorStack::get())
+            } else {
+                Ok(r.into())
+            }
+        }
+    }
+
+    /// Returns the result of `self` modulo `w`.
+    pub fn mod_word(&self, w: u32) -> Result<u64, ErrorStack> {
+        unsafe {
+            let r = ffi::BN_mod_word(self.as_ptr(), w.into());
+            if r == ffi::BN_ULONG::max_value() {
+                Err(ErrorStack::get())
+            } else {
+                Ok(r.into())
+            }
+        }
+    }
+
+    /// Places a cryptographically-secure pseudo-random number nonnegative
+    /// number less than `self` in `rnd`.
+    pub fn rand_range(&self, rnd: &mut BigNumRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_rand_range(self.as_ptr(), rnd.as_ptr())).map(|_| ()) }
+    }
+
+    /// The cryptographically weak counterpart to `rand_in_range`.
+    pub fn pseudo_rand_range(&self, rnd: &mut BigNumRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_pseudo_rand_range(self.as_ptr(), rnd.as_ptr())).map(|_| ()) }
+    }
+
+    /// Sets bit `n`. Equivalent to `self |= (1 << n)`.
+    ///
+    /// When setting a bit outside of `self`, it is expanded.
+    pub fn set_bit(&mut self, n: i32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_set_bit(self.as_ptr(), n.into())).map(|_| ()) }
+    }
+
+    /// Clears bit `n`, setting it to 0. Equivalent to `self &= ~(1 << n)`.
+    ///
+    /// When clearing a bit outside of `self`, an error is returned.
+    pub fn clear_bit(&mut self, n: i32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_clear_bit(self.as_ptr(), n.into())).map(|_| ()) }
+    }
+
+    /// Returns `true` if the `n`th bit of `self` is set to 1, `false` otherwise.
+    pub fn is_bit_set(&self, n: i32) -> bool {
+        unsafe { ffi::BN_is_bit_set(self.as_ptr(), n.into()) == 1 }
+    }
+
+    /// Truncates `self` to the lowest `n` bits.
+    ///
+    /// An error occurs if `self` is already shorter than `n` bits.
+    pub fn mask_bits(&mut self, n: i32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_mask_bits(self.as_ptr(), n.into())).map(|_| ()) }
+    }
+
+    /// Places `a << 1` in `self`.
+    pub fn lshift1(&mut self, a: &BigNumRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_lshift1(self.as_ptr(), a.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places `a >> 1` in `self`.
+    pub fn rshift1(&mut self, a: &BigNumRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_rshift1(self.as_ptr(), a.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places `a + b` in `self`.
+    pub fn checked_add(&mut self, a: &BigNumRef, b: &BigNumRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_add(self.as_ptr(), a.as_ptr(), b.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places `a - b` in `self`.
+    pub fn checked_sub(&mut self, a: &BigNumRef, b: &BigNumRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_sub(self.as_ptr(), a.as_ptr(), b.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places `a << n` in `self`.
+    pub fn lshift(&mut self, a: &BigNumRef, n: i32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_lshift(self.as_ptr(), a.as_ptr(), n.into())).map(|_| ()) }
+    }
+
+    /// Places `a >> n` in `self`.
+    pub fn rshift(&mut self, a: &BigNumRef, n: i32) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_rshift(self.as_ptr(), a.as_ptr(), n.into())).map(|_| ()) }
+    }
+
+    pub fn to_owned(&self) -> Result<BigNum, ErrorStack> {
+        unsafe { cvt_p(ffi::BN_dup(self.as_ptr())).map(|b| BigNum::from_ptr(b)) }
+    }
+
+    /// Sets the sign of `self`.
+    pub fn set_negative(&mut self, negative: bool) {
+        unsafe { ffi::BN_set_negative(self.as_ptr(), negative as c_int) }
+    }
+
+    /// Compare the absolute values of `self` and `oth`.
+    ///
+    /// ```
+    /// # use openssl::bn::BigNum;
+    /// # use std::cmp::Ordering;
+    /// let s = -BigNum::from_u32(8).unwrap();
+    /// let o = BigNum::from_u32(8).unwrap();
+    ///
+    /// assert_eq!(s.ucmp(&o), Ordering::Equal);
+    /// ```
+    pub fn ucmp(&self, oth: &BigNumRef) -> Ordering {
+        unsafe { ffi::BN_ucmp(self.as_ptr(), oth.as_ptr()).cmp(&0) }
+    }
+
+    pub fn is_negative(&self) -> bool {
+        self._is_negative()
+    }
+
+    #[cfg(ossl10x)]
+    fn _is_negative(&self) -> bool {
+        unsafe { (*self.as_ptr()).neg == 1 }
+    }
+
+    #[cfg(ossl110)]
+    fn _is_negative(&self) -> bool {
+        unsafe { ffi::BN_is_negative(self.as_ptr()) == 1 }
+    }
+
+    /// Returns the number of significant bits in `self`.
+    pub fn num_bits(&self) -> i32 {
+        unsafe { ffi::BN_num_bits(self.as_ptr()) as i32 }
+    }
+
+    /// Returns the size of `self` in bytes.
+    pub fn num_bytes(&self) -> i32 {
+        (self.num_bits() + 7) / 8
+    }
+
+    /// Generates a cryptographically strong pseudo-random `BigNum`, placing it in `self`.
+    ///
+    /// # Parameters
+    ///
+    /// * `bits`: Length of the number in bits.
+    /// * `msb`: The desired properties of the number.
+    /// * `odd`: If `true`, the generated number will be odd.
+    pub fn rand(&mut self, bits: i32, msb: MsbOption, odd: bool) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_rand(self.as_ptr(), bits.into(), msb.0, odd as c_int)).map(|_| ()) }
+    }
+
+    /// The cryptographically weak counterpart to `rand`.
+    pub fn pseudo_rand(&mut self, bits: i32, msb: MsbOption, odd: bool) -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_pseudo_rand(self.as_ptr(), bits.into(), msb.0, odd as c_int)).map(|_| ())
+        }
+    }
+
+    /// Generates a prime number, placing it in `self`.
+    ///
+    /// # Parameters
+    ///
+    /// * `bits`: The length of the prime in bits (lower bound).
+    /// * `safe`: If true, returns a "safe" prime `p` so that `(p-1)/2` is also prime.
+    /// * `add`/`rem`: If `add` is set to `Some(add)`, `p % add == rem` will hold, where `p` is the
+    ///   generated prime and `rem` is `1` if not specified (`None`).
+    pub fn generate_prime(&mut self,
+                          bits: i32,
+                          safe: bool,
+                          add: Option<&BigNumRef>,
+                          rem: Option<&BigNumRef>)
+                          -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_generate_prime_ex(self.as_ptr(),
+                                          bits as c_int,
+                                          safe as c_int,
+                                          add.map(|n| n.as_ptr()).unwrap_or(ptr::null_mut()),
+                                          rem.map(|n| n.as_ptr()).unwrap_or(ptr::null_mut()),
+                                          ptr::null_mut()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `a * b` in `self`.
+    pub fn checked_mul(&mut self,
+               a: &BigNumRef,
+               b: &BigNumRef,
+               ctx: &mut BigNumContextRef)
+               -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_mul(self.as_ptr(), a.as_ptr(), b.as_ptr(), ctx.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places the result of `a / b` in `self`.
+    pub fn checked_div(&mut self,
+                       a: &BigNumRef,
+                       b: &BigNumRef,
+                       ctx: &mut BigNumContextRef)
+                       -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_div(self.as_ptr(),
+                            ptr::null_mut(),
+                            a.as_ptr(),
+                            b.as_ptr(),
+                            ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `a % b` in `self`.
+    pub fn checked_rem(&mut self,
+                       a: &BigNumRef,
+                       b: &BigNumRef,
+                       ctx: &mut BigNumContextRef)
+                       -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_div(ptr::null_mut(),
+                            self.as_ptr(),
+                            a.as_ptr(),
+                            b.as_ptr(),
+                            ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `a / b` in `self` and `a % b` in `rem`.
+    pub fn div_rem(&mut self,
+                   rem: &mut BigNumRef,
+                   a: &BigNumRef,
+                   b: &BigNumRef,
+                   ctx: &mut BigNumContextRef)
+                   -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_div(self.as_ptr(),
+                            rem.as_ptr(),
+                            a.as_ptr(),
+                            b.as_ptr(),
+                            ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `a²` in `self`.
+    pub fn sqr(&mut self, a: &BigNumRef, ctx: &mut BigNumContextRef) -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_sqr(self.as_ptr(), a.as_ptr(), ctx.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places the result of `a mod m` in `self`.
+    pub fn nnmod(&mut self,
+                 a: &BigNumRef,
+                 m: &BigNumRef,
+                 ctx: &mut BigNumContextRef)
+                 -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_nnmod(self.as_ptr(), a.as_ptr(), m.as_ptr(), ctx.as_ptr())).map(|_| ())
+        }
+    }
+
+    /// Places the result of `(a + b) mod m` in `self`.
+    pub fn mod_add(&mut self,
+                   a: &BigNumRef,
+                   b: &BigNumRef,
+                   m: &BigNumRef,
+                   ctx: &mut BigNumContextRef)
+                   -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_mod_add(self.as_ptr(), a.as_ptr(), b.as_ptr(), m.as_ptr(), ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `(a - b) mod m` in `self`.
+    pub fn mod_sub(&mut self,
+                   a: &BigNumRef,
+                   b: &BigNumRef,
+                   m: &BigNumRef,
+                   ctx: &mut BigNumContextRef)
+                   -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_mod_sub(self.as_ptr(), a.as_ptr(), b.as_ptr(), m.as_ptr(), ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `(a * b) mod m` in `self`.
+    pub fn mod_mul(&mut self,
+                   a: &BigNumRef,
+                   b: &BigNumRef,
+                   m: &BigNumRef,
+                   ctx: &mut BigNumContextRef)
+                   -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_mod_mul(self.as_ptr(), a.as_ptr(), b.as_ptr(), m.as_ptr(), ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the result of `a² mod m` in `self`.
+    pub fn mod_sqr(&mut self,
+                   a: &BigNumRef,
+                   m: &BigNumRef,
+                   ctx: &mut BigNumContextRef)
+                   -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_mod_sqr(self.as_ptr(), a.as_ptr(), m.as_ptr(), ctx.as_ptr())).map(|_| ())
+        }
+    }
+
+    /// Places the result of `a^p` in `self`.
+    pub fn exp(&mut self,
+               a: &BigNumRef,
+               p: &BigNumRef,
+               ctx: &mut BigNumContextRef)
+               -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_exp(self.as_ptr(), a.as_ptr(), p.as_ptr(), ctx.as_ptr())).map(|_| ()) }
+    }
+
+    /// Places the result of `a^p mod m` in `self`.
+    pub fn mod_exp(&mut self,
+                   a: &BigNumRef,
+                   p: &BigNumRef,
+                   m: &BigNumRef,
+                   ctx: &mut BigNumContextRef)
+                   -> Result<(), ErrorStack> {
+        unsafe {
+            cvt(ffi::BN_mod_exp(self.as_ptr(), a.as_ptr(), p.as_ptr(), m.as_ptr(), ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the inverse of `a` modulo `n` in `self`.
+    pub fn mod_inverse(&mut self,
+                       a: &BigNumRef,
+                       n: &BigNumRef,
+                       ctx: &mut BigNumContextRef)
+                       -> Result<(), ErrorStack> {
+        unsafe {
+            cvt_p(ffi::BN_mod_inverse(self.as_ptr(), a.as_ptr(), n.as_ptr(), ctx.as_ptr()))
+                .map(|_| ())
+        }
+    }
+
+    /// Places the greatest common denominator of `a` and `b` in `self`.
+    pub fn gcd(&mut self,
+               a: &BigNumRef,
+               b: &BigNumRef,
+               ctx: &mut BigNumContextRef)
+               -> Result<(), ErrorStack> {
+        unsafe { cvt(ffi::BN_gcd(self.as_ptr(), a.as_ptr(), b.as_ptr(), ctx.as_ptr())).map(|_| ()) }
+    }
+
+    /// Checks whether `self` is prime.
+    ///
+    /// Performs a Miller-Rabin probabilistic primality test with `checks` iterations.
+    ///
+    /// Returns `true` if `self` is prime with an error probability of less than `0.25 ^ checks`.
+    pub fn is_prime(&self, checks: i32, ctx: &mut BigNumContextRef) -> Result<bool, ErrorStack> {
+        unsafe {
+            cvt_n(ffi::BN_is_prime_ex(self.as_ptr(), checks.into(), ctx.as_ptr(), ptr::null_mut()))
+                .map(|r| r != 0)
+        }
+    }
+
+    /// Checks whether `self` is prime with optional trial division.
+    ///
+    /// If `do_trial_division` is `true`, first performs trial division by a number of small primes.
+    /// Then, like `is_prime`, performs a Miller-Rabin probabilistic primality test with `checks`
+    /// iterations.
+    ///
+    /// # Return Value
+    ///
+    /// Returns `true` if `self` is prime with an error probability of less than `0.25 ^ checks`.
+    pub fn is_prime_fasttest(&self,
+                             checks: i32,
+                             ctx: &mut BigNumContextRef,
+                             do_trial_division: bool)
+                             -> Result<bool, ErrorStack> {
+        unsafe {
+            cvt_n(ffi::BN_is_prime_fasttest_ex(self.as_ptr(),
+                                               checks.into(),
+                                               ctx.as_ptr(),
+                                               do_trial_division as c_int,
+                                               ptr::null_mut()))
+                .map(|r| r != 0)
+        }
+    }
+
+    /// Returns a big-endian byte vector representation of the absolute value of `self`.
+    ///
+    /// `self` can be recreated by using `new_from_slice`.
+    ///
+    /// ```
+    /// # use openssl::bn::BigNum;
+    /// let s = -BigNum::from_u32(4543).unwrap();
+    /// let r = BigNum::from_u32(4543).unwrap();
+    ///
+    /// let s_vec = s.to_vec();
+    /// assert_eq!(BigNum::from_slice(&s_vec).unwrap(), r);
+    /// ```
+    pub fn to_vec(&self) -> Vec<u8> {
+        let size = self.num_bytes() as usize;
+        let mut v = Vec::with_capacity(size);
+        unsafe {
+            ffi::BN_bn2bin(self.as_ptr(), v.as_mut_ptr());
+            v.set_len(size);
+        }
+        v
+    }
+
+    /// Returns a decimal string representation of `self`.
+    ///
+    /// ```
+    /// # use openssl::bn::BigNum;
+    /// let s = -BigNum::from_u32(12345).unwrap();
+    ///
+    /// assert_eq!(&*s.to_dec_str().unwrap(), "-12345");
+    /// ```
+    pub fn to_dec_str(&self) -> Result<CryptoString, ErrorStack> {
+        unsafe {
+            let buf = try!(cvt_p(ffi::BN_bn2dec(self.as_ptr())));
+            Ok(CryptoString::from_null_terminated(buf))
+        }
+    }
+
+    /// Returns a hexadecimal string representation of `self`.
+    ///
+    /// ```
+    /// # use openssl::bn::BigNum;
+    /// let s = -BigNum::from_u32(0x99ff).unwrap();
+    ///
+    /// assert_eq!(&*s.to_hex_str().unwrap(), "-99FF");
+    /// ```
+    pub fn to_hex_str(&self) -> Result<CryptoString, ErrorStack> {
+        unsafe {
+            let buf = try!(cvt_p(ffi::BN_bn2hex(self.as_ptr())));
+            Ok(CryptoString::from_null_terminated(buf))
+        }
+    }
+}
+
+type_!(BigNum, BigNumRef, ffi::BIGNUM, ffi::BN_free);
+
+impl BigNum {
+    /// Creates a new `BigNum` with the value 0.
+    pub fn new() -> Result<BigNum, ErrorStack> {
+        unsafe {
+            ffi::init();
+            let v = try!(cvt_p(ffi::BN_new()));
+            Ok(BigNum::from_ptr(v))
+        }
+    }
+
+    /// Creates a new `BigNum` with the given value.
+    pub fn from_u32(n: u32) -> Result<BigNum, ErrorStack> {
+        BigNum::new().and_then(|v| unsafe {
+            cvt(ffi::BN_set_word(v.as_ptr(), n as ffi::BN_ULONG)).map(|_| v)
+        })
+    }
+
+    /// Creates a `BigNum` from a decimal string.
+    pub fn from_dec_str(s: &str) -> Result<BigNum, ErrorStack> {
+        unsafe {
+            let c_str = CString::new(s.as_bytes()).unwrap();
+            let mut bn = ptr::null_mut();
+            try!(cvt(ffi::BN_dec2bn(&mut bn, c_str.as_ptr() as *const _)));
+            Ok(BigNum::from_ptr(bn))
+        }
+    }
+
+    /// Creates a `BigNum` from a hexadecimal string.
+    pub fn from_hex_str(s: &str) -> Result<BigNum, ErrorStack> {
+        unsafe {
+            let c_str = CString::new(s.as_bytes()).unwrap();
+            let mut bn = ptr::null_mut();
+            try!(cvt(ffi::BN_hex2bn(&mut bn, c_str.as_ptr() as *const _)));
+            Ok(BigNum::from_ptr(bn))
+        }
+    }
+
+    /// Creates a new `BigNum` from an unsigned, big-endian encoded number of arbitrary length.
+    ///
+    /// ```
+    /// # use openssl::bn::BigNum;
+    /// let bignum = BigNum::from_slice(&[0x12, 0x00, 0x34]).unwrap();
+    ///
+    /// assert_eq!(bignum, BigNum::from_u32(0x120034).unwrap());
+    /// ```
+    pub fn from_slice(n: &[u8]) -> Result<BigNum, ErrorStack> {
+        unsafe {
+            assert!(n.len() <= c_int::max_value() as usize);
+            cvt_p(ffi::BN_bin2bn(n.as_ptr(), n.len() as c_int, ptr::null_mut()))
+                .map(|p| BigNum::from_ptr(p))
+        }
+    }
+}
+
+impl AsRef<BigNumRef> for BigNum {
+    fn as_ref(&self) -> &BigNumRef {
+        self.deref()
+    }
+}
+
+impl fmt::Debug for BigNumRef {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.to_dec_str() {
+            Ok(s) => f.write_str(&s),
+            Err(e) => Err(e.into()),
+        }
+    }
+}
+
+impl fmt::Debug for BigNum {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.to_dec_str() {
+            Ok(s) => f.write_str(&s),
+            Err(e) => Err(e.into()),
+        }
+    }
+}
+
+impl fmt::Display for BigNumRef {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.to_dec_str() {
+            Ok(s) => f.write_str(&s),
+            Err(e) => Err(e.into()),
+        }
+    }
+}
+
+impl fmt::Display for BigNum {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self.to_dec_str() {
+            Ok(s) => f.write_str(&s),
+            Err(e) => Err(e.into()),
+        }
+    }
+}
+
+impl PartialEq<BigNumRef> for BigNumRef {
+    fn eq(&self, oth: &BigNumRef) -> bool {
+        self.cmp(oth) == Ordering::Equal
+    }
+}
+
+impl PartialEq<BigNum> for BigNumRef {
+    fn eq(&self, oth: &BigNum) -> bool {
+        self.eq(oth.deref())
+    }
+}
+
+impl Eq for BigNumRef {}
+
+impl PartialEq for BigNum {
+    fn eq(&self, oth: &BigNum) -> bool {
+        self.deref().eq(oth)
+    }
+}
+
+impl PartialEq<BigNumRef> for BigNum {
+    fn eq(&self, oth: &BigNumRef) -> bool {
+        self.deref().eq(oth)
+    }
+}
+
+impl Eq for BigNum {}
+
+impl PartialOrd<BigNumRef> for BigNumRef {
+    fn partial_cmp(&self, oth: &BigNumRef) -> Option<Ordering> {
+        Some(self.cmp(oth))
+    }
+}
+
+impl PartialOrd<BigNum> for BigNumRef {
+    fn partial_cmp(&self, oth: &BigNum) -> Option<Ordering> {
+        Some(self.cmp(oth.deref()))
+    }
+}
+
+impl Ord for BigNumRef {
+    fn cmp(&self, oth: &BigNumRef) -> Ordering {
+        unsafe { ffi::BN_cmp(self.as_ptr(), oth.as_ptr()).cmp(&0) }
+    }
+}
+
+impl PartialOrd for BigNum {
+    fn partial_cmp(&self, oth: &BigNum) -> Option<Ordering> {
+        self.deref().partial_cmp(oth.deref())
+    }
+}
+
+impl PartialOrd<BigNumRef> for BigNum {
+    fn partial_cmp(&self, oth: &BigNumRef) -> Option<Ordering> {
+        self.deref().partial_cmp(oth)
+    }
+}
+
+impl Ord for BigNum {
+    fn cmp(&self, oth: &BigNum) -> Ordering {
+        self.deref().cmp(oth.deref())
+    }
+}
+
+macro_rules! delegate {
+    ($t:ident, $m:ident) => {
+        impl<'a, 'b> $t<&'b BigNum> for &'a BigNumRef {
+            type Output = BigNum;
+
+            fn $m(self, oth: &BigNum) -> BigNum {
+                $t::$m(self, oth.deref())
+            }
+        }
+
+        impl<'a, 'b> $t<&'b BigNumRef> for &'a BigNum {
+            type Output = BigNum;
+
+            fn $m(self, oth: &BigNumRef) -> BigNum {
+                $t::$m(self.deref(), oth)
+            }
+        }
+
+        impl<'a, 'b> $t<&'b BigNum> for &'a BigNum {
+            type Output = BigNum;
+
+            fn $m(self, oth: &BigNum) -> BigNum {
+                $t::$m(self.deref(), oth.deref())
+            }
+        }
+    }
+}
+
+impl<'a, 'b> Add<&'b BigNumRef> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn add(self, oth: &BigNumRef) -> BigNum {
+        let mut r = BigNum::new().unwrap();
+        r.checked_add(self, oth).unwrap();
+        r
+    }
+}
+
+delegate!(Add, add);
+
+impl<'a, 'b> Sub<&'b BigNumRef> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn sub(self, oth: &BigNumRef) -> BigNum {
+        let mut r = BigNum::new().unwrap();
+        r.checked_sub(self, oth).unwrap();
+        r
+    }
+}
+
+delegate!(Sub, sub);
+
+impl<'a, 'b> Mul<&'b BigNumRef> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn mul(self, oth: &BigNumRef) -> BigNum {
+        let mut ctx = BigNumContext::new().unwrap();
+        let mut r = BigNum::new().unwrap();
+        r.checked_mul(self, oth, &mut ctx).unwrap();
+        r
+    }
+}
+
+delegate!(Mul, mul);
+
+impl<'a, 'b> Div<&'b BigNumRef> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn div(self, oth: &'b BigNumRef) -> BigNum {
+        let mut ctx = BigNumContext::new().unwrap();
+        let mut r = BigNum::new().unwrap();
+        r.checked_div(self, oth, &mut ctx).unwrap();
+        r
+    }
+}
+
+delegate!(Div, div);
+
+impl<'a, 'b> Rem<&'b BigNumRef> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn rem(self, oth: &'b BigNumRef) -> BigNum {
+        let mut ctx = BigNumContext::new().unwrap();
+        let mut r = BigNum::new().unwrap();
+        r.checked_rem(self, oth, &mut ctx).unwrap();
+        r
+    }
+}
+
+delegate!(Rem, rem);
+
+impl<'a> Shl<i32> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn shl(self, n: i32) -> BigNum {
+        let mut r = BigNum::new().unwrap();
+        r.lshift(self, n).unwrap();
+        r
+    }
+}
+
+impl<'a> Shl<i32> for &'a BigNum {
+    type Output = BigNum;
+
+    fn shl(self, n: i32) -> BigNum {
+        self.deref().shl(n)
+    }
+}
+
+impl<'a> Shr<i32> for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn shr(self, n: i32) -> BigNum {
+        let mut r = BigNum::new().unwrap();
+        r.rshift(self, n).unwrap();
+        r
+    }
+}
+
+impl<'a> Shr<i32> for &'a BigNum {
+    type Output = BigNum;
+
+    fn shr(self, n: i32) -> BigNum {
+        self.deref().shl(n)
+    }
+}
+
+impl<'a> Neg for &'a BigNumRef {
+    type Output = BigNum;
+
+    fn neg(self) -> BigNum {
+        self.to_owned().unwrap().neg()
+    }
+}
+
+impl<'a> Neg for &'a BigNum {
+    type Output = BigNum;
+
+    fn neg(self) -> BigNum {
+        self.deref().neg()
+    }
+}
+
+impl Neg for BigNum {
+    type Output = BigNum;
+
+    fn neg(mut self) -> BigNum {
+        let negative = self.is_negative();
+        self.set_negative(!negative);
+        self
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use bn::{BigNumContext, BigNum};
+
+    #[test]
+    fn test_to_from_slice() {
+        let v0 = BigNum::from_u32(10203004).unwrap();
+        let vec = v0.to_vec();
+        let v1 = BigNum::from_slice(&vec).unwrap();
+
+        assert!(v0 == v1);
+    }
+
+    #[test]
+    fn test_negation() {
+        let a = BigNum::from_u32(909829283).unwrap();
+
+        assert!(!a.is_negative());
+        assert!((-a).is_negative());
+    }
+
+    #[test]
+    fn test_prime_numbers() {
+        let a = BigNum::from_u32(19029017).unwrap();
+        let mut p = BigNum::new().unwrap();
+        p.generate_prime(128, true, None, Some(&a)).unwrap();
+
+        let mut ctx = BigNumContext::new().unwrap();
+        assert!(p.is_prime(100, &mut ctx).unwrap());
+        assert!(p.is_prime_fasttest(100, &mut ctx, true).unwrap());
+    }
+}