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-rw-r--r--app/src/main/java/com/wireguard/crypto/Key.java255
-rw-r--r--app/src/main/java/com/wireguard/crypto/KeyEncoding.java161
-rw-r--r--app/src/main/java/com/wireguard/crypto/KeyPair.java81
-rw-r--r--app/src/main/java/com/wireguard/crypto/Keypair.java55
4 files changed, 336 insertions, 216 deletions
diff --git a/app/src/main/java/com/wireguard/crypto/Key.java b/app/src/main/java/com/wireguard/crypto/Key.java
new file mode 100644
index 00000000..85146794
--- /dev/null
+++ b/app/src/main/java/com/wireguard/crypto/Key.java
@@ -0,0 +1,255 @@
+/*
+ * Copyright © 2017-2018 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.crypto;
+
+import java.util.Arrays;
+
+/**
+ * Represents a WireGuard public or private key. This class uses specialized constant-time base64
+ * and hexadecimal codec implementations that resist side-channel attacks.
+ * <p>
+ * Instances of this class are immutable.
+ */
+@SuppressWarnings("MagicNumber")
+public final class Key {
+ private final byte[] key;
+
+ /**
+ * Constructs an object encapsulating the supplied key.
+ *
+ * @param key an array of bytes containing a binary key. Callers of this constructor are
+ * responsible for ensuring that the array is of the correct length.
+ */
+ private Key(final byte[] key) {
+ // Defensively copy to ensure immutability.
+ this.key = Arrays.copyOf(key, key.length);
+ }
+
+ /**
+ * Decodes a single 4-character base64 chunk to an integer in constant time.
+ *
+ * @param src an array of at least 4 characters in base64 format
+ * @param srcOffset the offset of the beginning of the chunk in {@code src}
+ * @return the decoded 3-byte integer, or some arbitrary integer value if the input was not
+ * valid base64
+ */
+ private static int decodeBase64(final char[] src, final int srcOffset) {
+ int val = 0;
+ for (int i = 0; i < 4; ++i) {
+ final char c = src[i + srcOffset];
+ val |= (-1
+ + ((((('A' - 1) - c) & (c - ('Z' + 1))) >>> 8) & (c - 64))
+ + ((((('a' - 1) - c) & (c - ('z' + 1))) >>> 8) & (c - 70))
+ + ((((('0' - 1) - c) & (c - ('9' + 1))) >>> 8) & (c + 5))
+ + ((((('+' - 1) - c) & (c - ('+' + 1))) >>> 8) & 63)
+ + ((((('/' - 1) - c) & (c - ('/' + 1))) >>> 8) & 64)
+ ) << (18 - 6 * i);
+ }
+ return val;
+ }
+
+ /**
+ * Encodes a single 4-character base64 chunk from 3 consecutive bytes in constant time.
+ *
+ * @param src an array of at least 3 bytes
+ * @param srcOffset the offset of the beginning of the chunk in {@code src}
+ * @param dest an array of at least 4 characters
+ * @param destOffset the offset of the beginning of the chunk in {@code dest}
+ */
+ private static void encodeBase64(final byte[] src, final int srcOffset,
+ final char[] dest, final int destOffset) {
+ final byte[] input = {
+ (byte) ((src[srcOffset] >>> 2) & 63),
+ (byte) ((src[srcOffset] << 4 | ((src[1 + srcOffset] & 0xff) >>> 4)) & 63),
+ (byte) ((src[1 + srcOffset] << 2 | ((src[2 + srcOffset] & 0xff) >>> 6)) & 63),
+ (byte) ((src[2 + srcOffset]) & 63),
+ };
+ for (int i = 0; i < 4; ++i) {
+ dest[i + destOffset] = (char) (input[i] + 'A'
+ + (((25 - input[i]) >>> 8) & 6)
+ - (((51 - input[i]) >>> 8) & 75)
+ - (((61 - input[i]) >>> 8) & 15)
+ + (((62 - input[i]) >>> 8) & 3));
+ }
+ }
+
+ /**
+ * Decodes a WireGuard public or private key from its base64 string representation. This
+ * function throws a {@link KeyFormatException} if the source string is not well-formed.
+ *
+ * @param str the base64 string representation of a WireGuard key
+ * @return the decoded key encapsulated in an immutable container
+ */
+ public static Key fromBase64(final String str) {
+ final char[] input = str.toCharArray();
+ if (input.length != Format.BASE64.length || input[Format.BASE64.length - 1] != '=')
+ throw new KeyFormatException(Format.BASE64);
+ final byte[] key = new byte[Format.BINARY.length];
+ int i;
+ int ret = 0;
+ for (i = 0; i < key.length / 3; ++i) {
+ final int val = decodeBase64(input, i * 4);
+ ret |= val >>> 31;
+ key[i * 3] = (byte) ((val >>> 16) & 0xff);
+ key[i * 3 + 1] = (byte) ((val >>> 8) & 0xff);
+ key[i * 3 + 2] = (byte) (val & 0xff);
+ }
+ final char[] endSegment = {
+ input[i * 4],
+ input[i * 4 + 1],
+ input[i * 4 + 2],
+ 'A',
+ };
+ final int val = decodeBase64(endSegment, 0);
+ ret |= (val >>> 31) | (val & 0xff);
+ key[i * 3] = (byte) ((val >>> 16) & 0xff);
+ key[i * 3 + 1] = (byte) ((val >>> 8) & 0xff);
+
+ if (ret != 0)
+ throw new KeyFormatException(Format.BASE64);
+ return new Key(key);
+ }
+
+ /**
+ * Wraps a WireGuard public or private key in an immutable container. This function throws a
+ * {@link KeyFormatException} if the source data is not the correct length.
+ *
+ * @param bytes an array of bytes containing a WireGuard key in binary format
+ * @return the key encapsulated in an immutable container
+ */
+ public static Key fromBytes(final byte[] bytes) {
+ if (bytes.length != Format.BINARY.length)
+ throw new KeyFormatException(Format.BINARY);
+ return new Key(bytes);
+ }
+
+ /**
+ * Decodes a WireGuard public or private key from its hexadecimal string representation. This
+ * function throws a {@link KeyFormatException} if the source string is not well-formed.
+ *
+ * @param str the hexadecimal string representation of a WireGuard key
+ * @return the decoded key encapsulated in an immutable container
+ */
+ public static Key fromHex(final String str) {
+ final char[] input = str.toCharArray();
+ if (input.length != Format.HEX.length)
+ throw new KeyFormatException(Format.HEX);
+ final byte[] key = new byte[Format.BINARY.length];
+ int ret = 0;
+ for (int i = 0; i < key.length; ++i) {
+ int c;
+ int cNum;
+ int cNum0;
+ int cAlpha;
+ int cAlpha0;
+ int cVal;
+ final int cAcc;
+
+ c = input[i * 2];
+ cNum = c ^ 48;
+ cNum0 = ((cNum - 10) >>> 8) & 0xff;
+ cAlpha = (c & ~32) - 55;
+ cAlpha0 = (((cAlpha - 10) ^ (cAlpha - 16)) >>> 8) & 0xff;
+ ret |= ((cNum0 | cAlpha0) - 1) >>> 8;
+ cVal = (cNum0 & cNum) | (cAlpha0 & cAlpha);
+ cAcc = cVal * 16;
+
+ c = input[i * 2 + 1];
+ cNum = c ^ 48;
+ cNum0 = ((cNum - 10) >>> 8) & 0xff;
+ cAlpha = (c & ~32) - 55;
+ cAlpha0 = (((cAlpha - 10) ^ (cAlpha - 16)) >>> 8) & 0xff;
+ ret |= ((cNum0 | cAlpha0) - 1) >>> 8;
+ cVal = (cNum0 & cNum) | (cAlpha0 & cAlpha);
+ key[i] = (byte) (cAcc | cVal);
+ }
+ if (ret != 0)
+ throw new KeyFormatException(Format.HEX);
+ return new Key(key);
+ }
+
+ /**
+ * Returns the key as an array of bytes.
+ *
+ * @return an array of bytes containing the raw binary key
+ */
+ public byte[] getBytes() {
+ // Defensively copy to ensure immutability.
+ return Arrays.copyOf(key, key.length);
+ }
+
+ /**
+ * Encodes the key to base64.
+ *
+ * @return a string containing the encoded key
+ */
+ public String toBase64() {
+ final char[] output = new char[Format.BASE64.length];
+ int i;
+ for (i = 0; i < key.length / 3; ++i)
+ encodeBase64(key, i * 3, output, i * 4);
+ final byte[] endSegment = {
+ key[i * 3],
+ key[i * 3 + 1],
+ 0,
+ };
+ encodeBase64(endSegment, 0, output, i * 4);
+ output[Format.BASE64.length - 1] = '=';
+ return new String(output);
+ }
+
+ /**
+ * Encodes the key to hexadecimal ASCII characters.
+ *
+ * @return a string containing the encoded key
+ */
+ public String toHex() {
+ final char[] output = new char[Format.HEX.length];
+ for (int i = 0; i < key.length; ++i) {
+ output[i * 2] = (char) (87 + (key[i] >> 4 & 0xf)
+ + ((((key[i] >> 4 & 0xf) - 10) >> 8) & ~38));
+ output[i * 2 + 1] = (char) (87 + (key[i] & 0xf)
+ + ((((key[i] & 0xf) - 10) >> 8) & ~38));
+ }
+ return new String(output);
+ }
+
+ /**
+ * The supported formats for encoding a WireGuard key.
+ */
+ public enum Format {
+ BASE64(44),
+ BINARY(32),
+ HEX(64);
+
+ private final int length;
+
+ Format(final int length) {
+ this.length = length;
+ }
+
+ public int getLength() {
+ return length;
+ }
+ }
+
+ /**
+ * An exception thrown when attempting to parse an invalid key (too short, too long, or byte
+ * data inappropriate for the format). The format being parsed can be accessed with the
+ * {@link #getFormat} method.
+ */
+ public static final class KeyFormatException extends RuntimeException {
+ private final Format format;
+
+ private KeyFormatException(final Format format) {
+ this.format = format;
+ }
+
+ public Format getFormat() {
+ return format;
+ }
+ }
+}
diff --git a/app/src/main/java/com/wireguard/crypto/KeyEncoding.java b/app/src/main/java/com/wireguard/crypto/KeyEncoding.java
deleted file mode 100644
index d29c2d44..00000000
--- a/app/src/main/java/com/wireguard/crypto/KeyEncoding.java
+++ /dev/null
@@ -1,161 +0,0 @@
-/*
- * Copyright © 2017-2018 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.crypto;
-
-import com.wireguard.android.Application;
-import com.wireguard.android.R;
-
-/**
- * This is a specialized constant-time base64 and hex implementation that resists side-channel attacks.
- */
-
-@SuppressWarnings("MagicNumber")
-public final class KeyEncoding {
- public static final int KEY_LENGTH = 32;
- public static final int KEY_LENGTH_BASE64 = 44;
- public static final int KEY_LENGTH_HEX = 64;
- private static final String KEY_LENGTH_BASE64_EXCEPTION_MESSAGE =
- Application.get().getString(R.string.key_length_base64_exception_message);
- private static final String KEY_LENGTH_EXCEPTION_MESSAGE =
- Application.get().getString(R.string.key_length_exception_message);
- private static final String KEY_LENGTH_HEX_EXCEPTION_MESSAGE =
- Application.get().getString(R.string.key_length_hex_exception_message);
-
- private KeyEncoding() {
- // Prevent instantiation.
- }
-
- private static int decodeBase64(final char[] src, final int srcOffset) {
- int val = 0;
- for (int i = 0; i < 4; ++i) {
- final char c = src[i + srcOffset];
- val |= (-1
- + ((((('A' - 1) - c) & (c - ('Z' + 1))) >>> 8) & (c - 64))
- + ((((('a' - 1) - c) & (c - ('z' + 1))) >>> 8) & (c - 70))
- + ((((('0' - 1) - c) & (c - ('9' + 1))) >>> 8) & (c + 5))
- + ((((('+' - 1) - c) & (c - ('+' + 1))) >>> 8) & 63)
- + ((((('/' - 1) - c) & (c - ('/' + 1))) >>> 8) & 64)
- ) << (18 - 6 * i);
- }
- return val;
- }
-
- private static void encodeBase64(final byte[] src, final int srcOffset,
- final char[] dest, final int destOffset) {
- final byte[] input = {
- (byte) ((src[srcOffset] >>> 2) & 63),
- (byte) ((src[srcOffset] << 4 | ((src[1 + srcOffset] & 0xff) >>> 4)) & 63),
- (byte) ((src[1 + srcOffset] << 2 | ((src[2 + srcOffset] & 0xff) >>> 6)) & 63),
- (byte) ((src[2 + srcOffset]) & 63),
- };
- for (int i = 0; i < 4; ++i) {
- dest[i + destOffset] = (char) (input[i] + 'A'
- + (((25 - input[i]) >>> 8) & 6)
- - (((51 - input[i]) >>> 8) & 75)
- - (((61 - input[i]) >>> 8) & 15)
- + (((62 - input[i]) >>> 8) & 3));
- }
- }
-
- public static byte[] keyFromBase64(final String str) {
- final char[] input = str.toCharArray();
- final byte[] key = new byte[KEY_LENGTH];
- if (input.length != KEY_LENGTH_BASE64 || input[KEY_LENGTH_BASE64 - 1] != '=')
- throw new IllegalArgumentException(KEY_LENGTH_BASE64_EXCEPTION_MESSAGE);
- int i;
- int ret = 0;
- for (i = 0; i < KEY_LENGTH / 3; ++i) {
- final int val = decodeBase64(input, i * 4);
- ret |= val >>> 31;
- key[i * 3] = (byte) ((val >>> 16) & 0xff);
- key[i * 3 + 1] = (byte) ((val >>> 8) & 0xff);
- key[i * 3 + 2] = (byte) (val & 0xff);
- }
- final char[] endSegment = {
- input[i * 4],
- input[i * 4 + 1],
- input[i * 4 + 2],
- 'A',
- };
- final int val = decodeBase64(endSegment, 0);
- ret |= (val >>> 31) | (val & 0xff);
- key[i * 3] = (byte) ((val >>> 16) & 0xff);
- key[i * 3 + 1] = (byte) ((val >>> 8) & 0xff);
-
- if (ret != 0)
- throw new IllegalArgumentException(KEY_LENGTH_BASE64_EXCEPTION_MESSAGE);
- return key;
- }
-
- public static byte[] keyFromHex(final String str) {
- final char[] input = str.toCharArray();
- final byte[] key = new byte[KEY_LENGTH];
- if (input.length != KEY_LENGTH_HEX)
- throw new IllegalArgumentException(KEY_LENGTH_HEX_EXCEPTION_MESSAGE);
- int ret = 0;
-
- for (int i = 0; i < KEY_LENGTH_HEX; i += 2) {
- int c;
- int cNum;
- int cNum0;
- int cAlpha;
- int cAlpha0;
- int cVal;
- final int cAcc;
-
- c = input[i];
- cNum = c ^ 48;
- cNum0 = ((cNum - 10) >>> 8) & 0xff;
- cAlpha = (c & ~32) - 55;
- cAlpha0 = (((cAlpha - 10) ^ (cAlpha - 16)) >>> 8) & 0xff;
- ret |= ((cNum0 | cAlpha0) - 1) >>> 8;
- cVal = (cNum0 & cNum) | (cAlpha0 & cAlpha);
- cAcc = cVal * 16;
-
- c = input[i + 1];
- cNum = c ^ 48;
- cNum0 = ((cNum - 10) >>> 8) & 0xff;
- cAlpha = (c & ~32) - 55;
- cAlpha0 = (((cAlpha - 10) ^ (cAlpha - 16)) >>> 8) & 0xff;
- ret |= ((cNum0 | cAlpha0) - 1) >>> 8;
- cVal = (cNum0 & cNum) | (cAlpha0 & cAlpha);
- key[i / 2] = (byte) (cAcc | cVal);
- }
- if (ret != 0)
- throw new IllegalArgumentException(KEY_LENGTH_HEX_EXCEPTION_MESSAGE);
- return key;
- }
-
- public static String keyToBase64(final byte[] key) {
- final char[] output = new char[KEY_LENGTH_BASE64];
- if (key.length != KEY_LENGTH)
- throw new IllegalArgumentException(KEY_LENGTH_EXCEPTION_MESSAGE);
- int i;
- for (i = 0; i < KEY_LENGTH / 3; ++i)
- encodeBase64(key, i * 3, output, i * 4);
- final byte[] endSegment = {
- key[i * 3],
- key[i * 3 + 1],
- 0,
- };
- encodeBase64(endSegment, 0, output, i * 4);
- output[KEY_LENGTH_BASE64 - 1] = '=';
- return new String(output);
- }
-
- public static String keyToHex(final byte[] key) {
- final char[] output = new char[KEY_LENGTH_HEX];
- if (key.length != KEY_LENGTH)
- throw new IllegalArgumentException(KEY_LENGTH_EXCEPTION_MESSAGE);
- for (int i = 0; i < KEY_LENGTH; ++i) {
- output[i * 2] = (char) (87 + (key[i] >> 4 & 0xf)
- + ((((key[i] >> 4 & 0xf) - 10) >> 8) & ~38));
- output[i * 2 + 1] = (char) (87 + (key[i] & 0xf)
- + ((((key[i] & 0xf) - 10) >> 8) & ~38));
- }
- return new String(output);
- }
-}
diff --git a/app/src/main/java/com/wireguard/crypto/KeyPair.java b/app/src/main/java/com/wireguard/crypto/KeyPair.java
new file mode 100644
index 00000000..2b2bf564
--- /dev/null
+++ b/app/src/main/java/com/wireguard/crypto/KeyPair.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright © 2017-2018 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.crypto;
+
+import java.security.SecureRandom;
+
+/**
+ * Represents a Curve25519 key pair as used by WireGuard.
+ * <p>
+ * Instances of this class are immutable.
+ */
+public class KeyPair {
+ private final Key privateKey;
+ private final Key publicKey;
+
+ /**
+ * Creates a key pair using a newly-generated private key.
+ */
+ public KeyPair() {
+ this(generatePrivateKey());
+ }
+
+ /**
+ * Creates a key pair using an existing private key.
+ *
+ * @param privateKey a private key, used to derive the public key
+ */
+ public KeyPair(final Key privateKey) {
+ this.privateKey = privateKey;
+ publicKey = generatePublicKey(privateKey);
+ }
+
+ /**
+ * Generates a private key using the system's {@link SecureRandom} number generator.
+ *
+ * @return a well-formed random private key
+ */
+ @SuppressWarnings("MagicNumber")
+ private static Key generatePrivateKey() {
+ final SecureRandom secureRandom = new SecureRandom();
+ final byte[] privateKey = new byte[Key.Format.BINARY.getLength()];
+ secureRandom.nextBytes(privateKey);
+ privateKey[0] &= 248;
+ privateKey[31] &= 127;
+ privateKey[31] |= 64;
+ return Key.fromBytes(privateKey);
+ }
+
+ /**
+ * Generates a public key from an existing private key.
+ *
+ * @param privateKey a private key
+ * @return a well-formed public key that corresponds to the supplied private key
+ */
+ private static Key generatePublicKey(final Key privateKey) {
+ final byte[] publicKey = new byte[Key.Format.BINARY.getLength()];
+ Curve25519.eval(publicKey, 0, privateKey.getBytes(), null);
+ return Key.fromBytes(publicKey);
+ }
+
+ /**
+ * Returns the private key from the key pair.
+ *
+ * @return the private key
+ */
+ public Key getPrivateKey() {
+ return privateKey;
+ }
+
+ /**
+ * Returns the public key from the key pair.
+ *
+ * @return the public key
+ */
+ public Key getPublicKey() {
+ return publicKey;
+ }
+}
diff --git a/app/src/main/java/com/wireguard/crypto/Keypair.java b/app/src/main/java/com/wireguard/crypto/Keypair.java
deleted file mode 100644
index 0ee27542..00000000
--- a/app/src/main/java/com/wireguard/crypto/Keypair.java
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * Copyright © 2017-2018 WireGuard LLC. All Rights Reserved.
- * SPDX-License-Identifier: Apache-2.0
- */
-
-package com.wireguard.crypto;
-
-import java.security.SecureRandom;
-
-/**
- * Represents a Curve25519 keypair as used by WireGuard.
- */
-
-public class Keypair {
- private final byte[] privateKey;
- private final byte[] publicKey;
-
- public Keypair() {
- this(generatePrivateKey());
- }
-
- private Keypair(final byte[] privateKey) {
- this.privateKey = privateKey;
- publicKey = generatePublicKey(privateKey);
- }
-
- public Keypair(final String privateKey) {
- this(KeyEncoding.keyFromBase64(privateKey));
- }
-
- @SuppressWarnings("MagicNumber")
- private static byte[] generatePrivateKey() {
- final SecureRandom secureRandom = new SecureRandom();
- final byte[] privateKey = new byte[KeyEncoding.KEY_LENGTH];
- secureRandom.nextBytes(privateKey);
- privateKey[0] &= 248;
- privateKey[31] &= 127;
- privateKey[31] |= 64;
- return privateKey;
- }
-
- private static byte[] generatePublicKey(final byte[] privateKey) {
- final byte[] publicKey = new byte[KeyEncoding.KEY_LENGTH];
- Curve25519.eval(publicKey, 0, privateKey, null);
- return publicKey;
- }
-
- public String getPrivateKey() {
- return KeyEncoding.keyToBase64(privateKey);
- }
-
- public String getPublicKey() {
- return KeyEncoding.keyToBase64(publicKey);
- }
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-15 13:34:46 +0000