io.netty.util.internal

Class ConstantTimeUtils

java.lang.Object

io.netty.util.internal.ConstantTimeUtils

public final class ConstantTimeUtils
extends Object

Method Summary

Modifier and Type	Method and Description
static int	equalsConstantTime(byte[] bytes1, int startPos1, byte[] bytes2, int startPos2, int length) Compare two byte arrays for equality without leaking timing information.
static int	equalsConstantTime(CharSequence s1, CharSequence s2) Compare two CharSequence objects without leaking timing information.
static int	equalsConstantTime(int x, int y) Compare two ints without leaking timing information.
static int	equalsConstantTime(long x, long y) Compare two longss without leaking timing information.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

equalsConstantTime

public static int equalsConstantTime(int x,
                                     int y)

Compare two ints without leaking timing information.

The int return type is intentional and is designed to allow cascading of constant time operations:

     int l1 = 1;
     int l2 = 1;
     int l3 = 1;
     int l4 = 500;
     boolean equals = (equalsConstantTime(l1, l2) & equalsConstantTime(l3, l4)) != 0;
 

Parameters:

x - the first value.

y - the second value.

Returns:

0 if not equal. 1 if equal.

equalsConstantTime

public static int equalsConstantTime(long x,
                                     long y)

Compare two longss without leaking timing information.

The int return type is intentional and is designed to allow cascading of constant time operations:

     long l1 = 1;
     long l2 = 1;
     long l3 = 1;
     long l4 = 500;
     boolean equals = (equalsConstantTime(l1, l2) & equalsConstantTime(l3, l4)) != 0;
 

Parameters:

x - the first value.

y - the second value.

Returns:

0 if not equal. 1 if equal.

equalsConstantTime

public static int equalsConstantTime(byte[] bytes1,
                                     int startPos1,
                                     byte[] bytes2,
                                     int startPos2,
                                     int length)

Compare two byte arrays for equality without leaking timing information. For performance reasons no bounds checking on the parameters is performed.

The int return type is intentional and is designed to allow cascading of constant time operations:

     byte[] s1 = new {1, 2, 3};
     byte[] s2 = new {1, 2, 3};
     byte[] s3 = new {1, 2, 3};
     byte[] s4 = new {4, 5, 6};
     boolean equals = (equalsConstantTime(s1, 0, s2, 0, s1.length) &
                       equalsConstantTime(s3, 0, s4, 0, s3.length)) != 0;
 

Parameters:

bytes1 - the first byte array.

startPos1 - the position (inclusive) to start comparing in bytes1.

bytes2 - the second byte array.

startPos2 - the position (inclusive) to start comparing in bytes2.

length - the amount of bytes to compare. This is assumed to be validated as not going out of bounds by the caller.

Returns:

0 if not equal. 1 if equal.

equalsConstantTime

public static int equalsConstantTime(CharSequence s1,
                                     CharSequence s2)

Compare two CharSequence objects without leaking timing information.

The int return type is intentional and is designed to allow cascading of constant time operations:

     String s1 = "foo";
     String s2 = "foo";
     String s3 = "foo";
     String s4 = "goo";
     boolean equals = (equalsConstantTime(s1, s2) & equalsConstantTime(s3, s4)) != 0;
 

Parameters:

s1 - the first value.

s2 - the second value.

Returns:

0 if not equal. 1 if equal.