diff options
author | Harsh Shandilya <me@msfjarvis.dev> | 2018-05-05 16:26:52 +0530 |
---|---|---|
committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2018-05-09 18:16:14 +0200 |
commit | 0b9bcf0f9e25122f9ee351aa9c889ebb01a238f5 (patch) | |
tree | e7e66720eca79145348adb82b763a0ee10685b3a /app/src/main/java/com/wireguard/crypto/Curve25519.java | |
parent | e2ab2210cdda2d598c213f07dbc1d1199499ffd3 (diff) |
global: Cleanup line lengths and misc lint warnings
I know we decided to ditch the idea of shutting up "Exception
thrown with empty param" warnings but this pesters me too
much and we can instead just treat this as a weird future proofing
thing if and when we end up needing the exception messages.
Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>
Diffstat (limited to 'app/src/main/java/com/wireguard/crypto/Curve25519.java')
-rw-r--r-- | app/src/main/java/com/wireguard/crypto/Curve25519.java | 111 |
1 files changed, 56 insertions, 55 deletions
diff --git a/app/src/main/java/com/wireguard/crypto/Curve25519.java b/app/src/main/java/com/wireguard/crypto/Curve25519.java index 694f557b..a20c9f97 100644 --- a/app/src/main/java/com/wireguard/crypto/Curve25519.java +++ b/app/src/main/java/com/wireguard/crypto/Curve25519.java @@ -21,28 +21,28 @@ import java.util.Arrays; * <p> * References: http://cr.yp.to/ecdh.html, RFC 7748 */ -@SuppressWarnings("ALL") +@SuppressWarnings("MagicNumber") public final class Curve25519 { // Numbers modulo 2^255 - 19 are broken up into ten 26-bit words. private static final int NUM_LIMBS_255BIT = 10; private static final int NUM_LIMBS_510BIT = 20; - private int[] A; - private int[] AA; - private int[] B; - private int[] BB; - private int[] C; - private int[] CB; - private int[] D; - private int[] DA; - private int[] E; - private long[] t1; - private int[] t2; - private int[] x_1; - private int[] x_2; - private int[] x_3; - private int[] z_2; - private int[] z_3; + private final int[] A; + private final int[] AA; + private final int[] B; + private final int[] BB; + private final int[] C; + private final int[] CB; + private final int[] D; + private final int[] DA; + private final int[] E; + private final long[] t1; + private final int[] t2; + private final int[] x_1; + private final int[] x_2; + private final int[] x_3; + private final int[] z_2; + private final int[] z_3; /** * Constructs the temporary state holder for Curve25519 evaluation. @@ -74,11 +74,10 @@ public final class Curve25519 { * @param x The first value. * @param y The second value. */ - private static void cswap(int select, int[] x, int[] y) { - int dummy; + private static void cswap(int select, final int[] x, final int[] y) { select = -select; for (int index = 0; index < NUM_LIMBS_255BIT; ++index) { - dummy = select & (x[index] ^ y[index]); + final int dummy = select & (x[index] ^ y[index]); x[index] ^= dummy; y[index] ^= dummy; } @@ -93,17 +92,18 @@ public final class Curve25519 { * @param publicKey The public key to use in the evaluation, or null * if the base point of the curve should be used. */ - public static void eval(byte[] result, int offset, byte[] privateKey, byte[] publicKey) { - Curve25519 state = new Curve25519(); + public static void eval(final byte[] result, final int offset, + final byte[] privateKey, final byte[] publicKey) { + final Curve25519 state = new Curve25519(); try { // Unpack the public key value. If null, use 9 as the base point. Arrays.fill(state.x_1, 0); if (publicKey != null) { // Convert the input value from little-endian into 26-bit limbs. for (int index = 0; index < 32; ++index) { - int bit = (index * 8) % 26; - int word = (index * 8) / 26; - int value = publicKey[index] & 0xFF; + final int bit = (index * 8) % 26; + final int word = (index * 8) / 26; + final int value = publicKey[index] & 0xFF; if (bit <= (26 - 8)) { state.x_1[word] |= value << bit; } else { @@ -139,8 +139,8 @@ public final class Curve25519 { // Convert x_2 into little-endian in the result buffer. for (int index = 0; index < 32; ++index) { - int bit = (index * 8) % 26; - int word = (index * 8) / 26; + final int bit = (index * 8) % 26; + final int word = (index * 8) / 26; if (bit <= (26 - 8)) result[offset + index] = (byte) (state.x_2[word] >> bit); else @@ -159,11 +159,11 @@ public final class Curve25519 { * @param x The first number to add. * @param y The second number to add. */ - private void add(int[] result, int[] x, int[] y) { - int index, carry; + private void add(final int[] result, final int[] x, final int[] y) { + int carry; carry = x[0] + y[0]; result[0] = carry & 0x03FFFFFF; - for (index = 1; index < NUM_LIMBS_255BIT; ++index) { + for (int index = 1; index < NUM_LIMBS_255BIT; ++index) { carry = (carry >> 26) + x[index] + y[index]; result[index] = carry & 0x03FFFFFF; } @@ -198,19 +198,17 @@ public final class Curve25519 { * * @param s The 32-byte secret key. */ - private void evalCurve(byte[] s) { + private void evalCurve(final byte[] s) { int sposn = 31; - int sbit = 6; int svalue = s[sposn] | 0x40; int swap = 0; - int select; // Iterate over all 255 bits of "s" from the highest to the lowest. // We ignore the high bit of the 256-bit representation of "s". - for (; ; ) { + for (int sbit = 6; ; ) { // Conditional swaps on entry to this bit but only if we // didn't swap on the previous bit. - select = (svalue >> sbit) & 0x01; + final int select = (svalue >> sbit) & 0x01; swap ^= select; cswap(swap, x_2, x_3); cswap(swap, z_2, z_3); @@ -264,8 +262,8 @@ public final class Curve25519 { * @param x The first number to multiply. * @param y The second number to multiply. */ - private void mul(int[] result, int[] x, int[] y) { - int i, j; + private void mul(final int[] result, final int[] x, final int[] y) { + int i; // Multiply the two numbers to create the intermediate result. long v = x[0]; @@ -274,7 +272,7 @@ public final class Curve25519 { } for (i = 1; i < NUM_LIMBS_255BIT; ++i) { v = x[i]; - for (j = 0; j < (NUM_LIMBS_255BIT - 1); ++j) { + for (int j = 0; j < (NUM_LIMBS_255BIT - 1); ++j) { t1[i + j] += v * y[j]; } t1[i + NUM_LIMBS_255BIT - 1] = v * y[NUM_LIMBS_255BIT - 1]; @@ -298,11 +296,10 @@ public final class Curve25519 { * @param result The result. * @param x The number to multiply by a24. */ - private void mulA24(int[] result, int[] x) { - long a24 = 121665; + private void mulA24(final int[] result, final int[] x) { + final long a24 = 121665; long carry = 0; - int index; - for (index = 0; index < NUM_LIMBS_255BIT; ++index) { + for (int index = 0; index < NUM_LIMBS_255BIT; ++index) { carry += a24 * x[index]; t2[index] = ((int) carry) & 0x03FFFFFF; carry >>= 26; @@ -317,8 +314,8 @@ public final class Curve25519 { * @param result The result. Must not overlap with x. * @param x The argument. */ - private void pow250(int[] result, int[] x) { - int i, j; + private void pow250(final int[] result, final int[] x) { + int j; // The big-endian hexadecimal expansion of (2^250 - 1) is: // 03FFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF @@ -335,7 +332,7 @@ public final class Curve25519 { for (j = 0; j < 9; ++j) square(A, A); mul(result, A, x); - for (i = 0; i < 23; ++i) { + for (int i = 0; i < 23; ++i) { for (j = 0; j < 10; ++j) square(A, A); mul(result, result, A); @@ -357,7 +354,7 @@ public final class Curve25519 { * @param result The result. Must not overlap with x. * @param x The argument. */ - private void recip(int[] result, int[] x) { + private void recip(final int[] result, final int[] x) { // The reciprocal is the same as x ^ (p - 2) where p = 2^255 - 19. // The big-endian hexadecimal expansion of (p - 2) is: // 7FFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFEB @@ -383,8 +380,10 @@ public final class Curve25519 { * modified during the reduction. * @param size The number of limbs in the high order half of x. */ - private void reduce(int[] result, int[] x, int size) { - int index, limb, carry; + private void reduce(final int[] result, final int[] x, final int size) { + int index; + int limb; + int carry; // Calculate (x mod 2^255) + ((x / 2^255) * 19) which will // either produce the answer we want or it will produce a @@ -436,8 +435,9 @@ public final class Curve25519 { * * @param x The number to reduce, and the result. */ - private void reduceQuick(int[] x) { - int index, carry; + private void reduceQuick(final int[] x) { + int index; + int carry; // Perform a trial subtraction of (2^255 - 19) from "x" which is // equivalent to adding 19 and subtracting 2^255. We add 19 here; @@ -454,8 +454,8 @@ public final class Curve25519 { // correct answer but do it in a way that instruction timing will not // reveal which value was selected. Borrow will occur if bit 21 of // "t2" is zero. Turn the bit into a selection mask. - int mask = -((t2[NUM_LIMBS_255BIT - 1] >> 21) & 0x01); - int nmask = ~mask; + final int mask = -((t2[NUM_LIMBS_255BIT - 1] >> 21) & 0x01); + final int nmask = ~mask; t2[NUM_LIMBS_255BIT - 1] &= 0x001FFFFF; for (index = 0; index < NUM_LIMBS_255BIT; ++index) x[index] = (x[index] & nmask) | (t2[index] & mask); @@ -467,7 +467,7 @@ public final class Curve25519 { * @param result The result. * @param x The number to square. */ - private void square(int[] result, int[] x) { + private void square(final int[] result, final int[] x) { mul(result, x, x); } @@ -478,8 +478,9 @@ public final class Curve25519 { * @param x The first number to subtract. * @param y The second number to subtract. */ - private void sub(int[] result, int[] x, int[] y) { - int index, borrow; + private static void sub(final int[] result, final int[] x, final int[] y) { + int index; + int borrow; // Subtract y from x to generate the intermediate result. borrow = 0; |