Rename subtle::arrays_equal_ct() to subtle::arrays_equal().

It's already obvious that it's constant-time because it's in the subtle
module.

src/curve.rs

@@ -90,7 +90,7 @@ use core::ops::Index;
 use constants;
 use field::FieldElement;
 use scalar::Scalar;
-use subtle::arrays_equal_ct;
+use subtle::arrays_equal;
 use subtle::bytes_equal_ct;
 use subtle::CTAssignable;
 use subtle::CTEq;
@@ -518,8 +518,8 @@ impl CTAssignable for ExtendedPoint {
 
 impl CTEq for ExtendedPoint {
     fn ct_eq(&self, other: &ExtendedPoint) -> u8 {
-        arrays_equal_ct( self.compress_edwards().as_bytes(),
-                        other.compress_edwards().as_bytes())
+        arrays_equal( self.compress_edwards().as_bytes(),
+                      other.compress_edwards().as_bytes())
     }
 }
 

src/field.rs

@@ -23,7 +23,7 @@ use core::ops::{Index, IndexMut};
 use core::cmp::{Eq, PartialEq};
 use core::ops::Neg;
 
-use subtle::arrays_equal_ct;
+use subtle::arrays_equal;
 use subtle::byte_is_nonzero;
 use subtle::CTAssignable;
 use subtle::CTEq;
@@ -96,7 +96,7 @@ impl CTEq for FieldElement {
     ///
     /// `1u8` if the two `FieldElement`s are equal, and `0u8` otherwise.
     fn ct_eq(&self, other: &FieldElement) -> u8 {
-        arrays_equal_ct(&self.to_bytes(), &other.to_bytes())
+        arrays_equal(&self.to_bytes(), &other.to_bytes())
     }
 }
 

src/scalar.rs

@@ -47,7 +47,7 @@ use constants;
 use utils::{load3, load4};
 use subtle::CTAssignable;
 use subtle::CTEq;
-use subtle::arrays_equal_ct;
+use subtle::arrays_equal;
 
 /// The `Scalar` struct represents an element in ℤ/lℤ, where
 ///
@@ -76,7 +76,7 @@ impl PartialEq for Scalar {
     ///
     /// True if they are equal, and false otherwise.
     fn eq(&self, other: &Self) -> bool {
-        arrays_equal_ct(&self.0, &other.0) == 1u8
+        arrays_equal(&self.0, &other.0) == 1u8
     }
 }
 
@@ -87,7 +87,7 @@ impl CTEq for Scalar {
     ///
     /// `1u8` if they are equal, and `0u8` otherwise.
     fn ct_eq(&self, other: &Self) -> u8 {
-        arrays_equal_ct(&self.0, &other.0)
+        arrays_equal(&self.0, &other.0)
     }
 }
 

src/subtle.rs

@@ -101,12 +101,12 @@ pub fn byte_is_nonzero(b: u8) -> u8 {
 ///
 /// ```
 /// # extern crate curve25519_dalek;
-/// # use curve25519_dalek::subtle::arrays_equal_ct;
+/// # use curve25519_dalek::subtle::arrays_equal;
 /// # fn main() {
 /// let a: [u8; 3] = [0, 1, 2];
 /// let b: [u8; 3] = [1, 2, 3];
 ///
-/// assert!(arrays_equal_ct(&a, &b) == 0);
+/// assert!(arrays_equal(&a, &b) == 0);
 /// # }
 /// ```
 ///
@@ -114,12 +114,12 @@ pub fn byte_is_nonzero(b: u8) -> u8 {
 ///
 /// ```
 /// # extern crate curve25519_dalek;
-/// # use curve25519_dalek::subtle::arrays_equal_ct;
+/// # use curve25519_dalek::subtle::arrays_equal;
 /// # fn main() {
 /// let a: [u8; 3] = [0, 1, 2];
 /// let b: [u8; 3] = [0, 1, 2];
 ///
-/// assert!(arrays_equal_ct(&a, &b) == 1);
+/// assert!(arrays_equal(&a, &b) == 1);
 /// # }
 /// ```
 ///
@@ -131,7 +131,7 @@ pub fn byte_is_nonzero(b: u8) -> u8 {
 ///
 /// Returns `1u8` if `a == b` and `0u8` otherwise.
 #[inline(always)]
-pub fn arrays_equal_ct(a: &[u8; 32], b: &[u8; 32]) -> u8 {
+pub fn arrays_equal(a: &[u8; 32], b: &[u8; 32]) -> u8 {
     let mut x: u8 = 0;
 
     for i in 0..32 {