diff --git a/kotlin/diffie-hellman/.exercism/metadata.json b/kotlin/diffie-hellman/.exercism/metadata.json new file mode 100644 index 0000000..44093de --- /dev/null +++ b/kotlin/diffie-hellman/.exercism/metadata.json @@ -0,0 +1 @@ +{"track":"kotlin","exercise":"diffie-hellman","id":"9ef41385712144a4af4b0463a377ace9","url":"https://exercism.io/my/solutions/9ef41385712144a4af4b0463a377ace9","handle":"anthonycicc","is_requester":true,"auto_approve":false} \ No newline at end of file diff --git a/kotlin/diffie-hellman/.gradle/6.0.1/executionHistory/executionHistory.bin b/kotlin/diffie-hellman/.gradle/6.0.1/executionHistory/executionHistory.bin new file mode 100644 index 0000000..981d515 Binary files /dev/null and b/kotlin/diffie-hellman/.gradle/6.0.1/executionHistory/executionHistory.bin differ diff --git a/kotlin/diffie-hellman/.gradle/6.0.1/executionHistory/executionHistory.lock b/kotlin/diffie-hellman/.gradle/6.0.1/executionHistory/executionHistory.lock new file mode 100644 index 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b/kotlin/diffie-hellman/.gradle/buildOutputCleanup/cache.properties @@ -0,0 +1,2 @@ +#Thu Mar 05 17:45:28 EST 2020 +gradle.version=6.0.1 diff --git a/kotlin/diffie-hellman/.gradle/buildOutputCleanup/outputFiles.bin b/kotlin/diffie-hellman/.gradle/buildOutputCleanup/outputFiles.bin new file mode 100644 index 0000000..ee07e34 Binary files /dev/null and b/kotlin/diffie-hellman/.gradle/buildOutputCleanup/outputFiles.bin differ diff --git a/kotlin/diffie-hellman/.gradle/vcs-1/gc.properties b/kotlin/diffie-hellman/.gradle/vcs-1/gc.properties new file mode 100644 index 0000000..e69de29 diff --git a/kotlin/diffie-hellman/.idea/.gitignore b/kotlin/diffie-hellman/.idea/.gitignore new file mode 100644 index 0000000..73f69e0 --- /dev/null +++ b/kotlin/diffie-hellman/.idea/.gitignore @@ -0,0 +1,8 @@ +# Default ignored files +/shelf/ +/workspace.xml +# Datasource local storage ignored files +/dataSources/ +/dataSources.local.xml +# Editor-based HTTP Client requests +/httpRequests/ diff --git a/kotlin/diffie-hellman/.idea/compiler.xml b/kotlin/diffie-hellman/.idea/compiler.xml new file mode 100644 index 0000000..7e7ee62 --- /dev/null +++ b/kotlin/diffie-hellman/.idea/compiler.xml @@ -0,0 +1,6 @@ + + + + + + \ No newline at end of file diff --git a/kotlin/diffie-hellman/.idea/jarRepositories.xml b/kotlin/diffie-hellman/.idea/jarRepositories.xml new file mode 100644 index 0000000..efa4625 --- /dev/null +++ b/kotlin/diffie-hellman/.idea/jarRepositories.xml @@ -0,0 +1,20 @@ + + + + + + + + + + + \ No newline at end of file diff --git a/kotlin/diffie-hellman/.idea/misc.xml b/kotlin/diffie-hellman/.idea/misc.xml new file mode 100644 index 0000000..b9d0e72 --- /dev/null +++ b/kotlin/diffie-hellman/.idea/misc.xml @@ -0,0 +1,8 @@ + + + + + + + + \ No newline at end of file diff --git a/kotlin/diffie-hellman/.idea/vcs.xml b/kotlin/diffie-hellman/.idea/vcs.xml new file mode 100644 index 0000000..b2bdec2 --- /dev/null +++ b/kotlin/diffie-hellman/.idea/vcs.xml @@ -0,0 +1,6 @@ + + + + + + \ No newline at end of file diff --git a/kotlin/diffie-hellman/README.md b/kotlin/diffie-hellman/README.md new file mode 100644 index 0000000..d98aac1 --- /dev/null +++ b/kotlin/diffie-hellman/README.md @@ -0,0 +1,69 @@ +# Diffie-Hellman + +Diffie-Hellman key exchange. + +Alice and Bob use Diffie-Hellman key exchange to share secrets. They +start with prime numbers, pick private keys, generate and share public +keys, and then generate a shared secret key. + +## Step 0 + +The test program supplies prime numbers p and g. + +## Step 1 + +Alice picks a private key, a, greater than 1 and less than p. Bob does +the same to pick a private key b. + +## Step 2 + +Alice calculates a public key A. + + A = g**a mod p + +Using the same p and g, Bob similarly calculates a public key B from his +private key b. + +## Step 3 + +Alice and Bob exchange public keys. Alice calculates secret key s. + + s = B**a mod p + +Bob calculates + + s = A**b mod p + +The calculations produce the same result! Alice and Bob now share +secret s. + +## Setup + +Go through the setup instructions for Kotlin to install the necessary +dependencies: + +[https://exercism.io/tracks/kotlin/installation](https://exercism.io/tracks/kotlin/installation) + +## Making the test suite pass + +Execute the tests with: + +```bash +$ gradlew test +``` + +> Use `gradlew.bat` if you're on Windows + +In the test suites all tests but the first have been skipped. + +Once you get a test passing, you can enable the next one by removing the +`@Ignore` annotation. + +## Source + +Wikipedia, 1024 bit key from www.cryptopp.com/wiki. [http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange](http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange) + +## Submitting Incomplete Solutions + +It's possible to submit an incomplete solution so you can see how others have +completed the exercise. diff --git a/kotlin/diffie-hellman/build.gradle.kts b/kotlin/diffie-hellman/build.gradle.kts new file mode 100644 index 0000000..1793ac4 --- /dev/null +++ b/kotlin/diffie-hellman/build.gradle.kts @@ -0,0 +1,23 @@ +import org.gradle.api.tasks.testing.logging.TestExceptionFormat + +plugins { + kotlin("jvm") version "1.3.60" +} + +repositories { + jcenter() +} + +dependencies { + compile(kotlin("stdlib")) + + testImplementation("junit:junit:4.12") + testImplementation(kotlin("test-junit")) +} + +tasks.withType { + testLogging { + exceptionFormat = TestExceptionFormat.FULL + events("passed", "failed", "skipped") + } +} diff --git a/kotlin/diffie-hellman/gradle/wrapper/gradle-wrapper.properties b/kotlin/diffie-hellman/gradle/wrapper/gradle-wrapper.properties new file mode 100644 index 0000000..9492014 --- /dev/null +++ b/kotlin/diffie-hellman/gradle/wrapper/gradle-wrapper.properties @@ -0,0 +1,5 @@ +distributionBase=GRADLE_USER_HOME +distributionPath=wrapper/dists +distributionUrl=https\://services.gradle.org/distributions/gradle-6.0.1-bin.zip +zipStoreBase=GRADLE_USER_HOME +zipStorePath=wrapper/dists diff --git a/kotlin/diffie-hellman/gradlew b/kotlin/diffie-hellman/gradlew new file mode 100644 index 0000000..83f2acf --- /dev/null +++ b/kotlin/diffie-hellman/gradlew @@ -0,0 +1,188 @@ +#!/usr/bin/env sh + +# +# Copyright 2015 the original author or authors. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# https://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# + +############################################################################## +## +## Gradle start up script for UN*X +## +############################################################################## + +# Attempt to set APP_HOME +# Resolve links: $0 may be a link +PRG="$0" +# Need this for relative symlinks. +while [ -h "$PRG" ] ; do + ls=`ls -ld "$PRG"` + link=`expr "$ls" : '.*-> \(.*\)$'` + if expr "$link" : '/.*' > /dev/null; then + PRG="$link" + else + PRG=`dirname "$PRG"`"/$link" + fi +done +SAVED="`pwd`" +cd "`dirname \"$PRG\"`/" >/dev/null +APP_HOME="`pwd -P`" +cd "$SAVED" >/dev/null + +APP_NAME="Gradle" +APP_BASE_NAME=`basename "$0"` + +# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. +DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"' + +# Use the maximum available, or set MAX_FD != -1 to use that value. +MAX_FD="maximum" + +warn () { + echo "$*" +} + +die () { + echo + echo "$*" + echo + exit 1 +} + +# OS specific support (must be 'true' or 'false'). +cygwin=false +msys=false +darwin=false +nonstop=false +case "`uname`" in + CYGWIN* ) + cygwin=true + ;; + Darwin* ) + darwin=true + ;; + MINGW* ) + msys=true + ;; + NONSTOP* ) + nonstop=true + ;; +esac + +CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar + +# Determine the Java command to use to start the JVM. +if [ -n "$JAVA_HOME" ] ; then + if [ -x "$JAVA_HOME/jre/sh/java" ] ; then + # IBM's JDK on AIX uses strange locations for the executables + JAVACMD="$JAVA_HOME/jre/sh/java" + else + JAVACMD="$JAVA_HOME/bin/java" + fi + if [ ! -x "$JAVACMD" ] ; then + die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME + +Please set the JAVA_HOME variable in your environment to match the +location of your Java installation." + fi +else + JAVACMD="java" + which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. + +Please set the JAVA_HOME variable in your environment to match the +location of your Java installation." +fi + +# Increase the maximum file descriptors if we can. +if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then + MAX_FD_LIMIT=`ulimit -H -n` + if [ $? -eq 0 ] ; then + if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then + MAX_FD="$MAX_FD_LIMIT" + fi + ulimit -n $MAX_FD + if [ $? -ne 0 ] ; then + warn "Could not set maximum file descriptor limit: $MAX_FD" + fi + else + warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT" + fi +fi + +# For Darwin, add options to specify how the application appears in the dock +if $darwin; then + GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\"" +fi + +# For Cygwin or MSYS, switch paths to Windows format before running java +if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then + APP_HOME=`cygpath --path --mixed "$APP_HOME"` + CLASSPATH=`cygpath --path --mixed "$CLASSPATH"` + JAVACMD=`cygpath --unix "$JAVACMD"` + + # We build the pattern for arguments to be converted via cygpath + ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null` + SEP="" + for dir in $ROOTDIRSRAW ; do + ROOTDIRS="$ROOTDIRS$SEP$dir" + SEP="|" + done + OURCYGPATTERN="(^($ROOTDIRS))" + # Add a user-defined pattern to the cygpath arguments + if [ "$GRADLE_CYGPATTERN" != "" ] ; then + OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)" + fi + # Now convert the arguments - kludge to limit ourselves to /bin/sh + i=0 + for arg in "$@" ; do + CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -` + CHECK2=`echo "$arg"|egrep -c "^-"` ### Determine if an option + + if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then ### Added a condition + eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"` + else + eval `echo args$i`="\"$arg\"" + fi + i=$((i+1)) + done + case $i in + (0) set -- ;; + (1) set -- "$args0" ;; + (2) set -- "$args0" "$args1" ;; + (3) set -- "$args0" "$args1" "$args2" ;; + (4) set -- "$args0" "$args1" "$args2" "$args3" ;; + (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;; + (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;; + (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;; + (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;; + (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;; + esac +fi + +# Escape application args +save () { + for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done + echo " " +} +APP_ARGS=$(save "$@") + +# Collect all arguments for the java command, following the shell quoting and substitution rules +eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS" + +# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong +if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then + cd "$(dirname "$0")" +fi + +exec "$JAVACMD" "$@" diff --git a/kotlin/diffie-hellman/gradlew.bat b/kotlin/diffie-hellman/gradlew.bat new file mode 100644 index 0000000..9618d8d --- /dev/null +++ b/kotlin/diffie-hellman/gradlew.bat @@ -0,0 +1,100 @@ +@rem +@rem Copyright 2015 the original author or authors. +@rem +@rem Licensed under the Apache License, Version 2.0 (the "License"); +@rem you may not use this file except in compliance with the License. +@rem You may obtain a copy of the License at +@rem +@rem https://www.apache.org/licenses/LICENSE-2.0 +@rem +@rem Unless required by applicable law or agreed to in writing, software +@rem distributed under the License is distributed on an "AS IS" BASIS, +@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +@rem See the License for the specific language governing permissions and +@rem limitations under the License. +@rem + +@if "%DEBUG%" == "" @echo off +@rem ########################################################################## +@rem +@rem Gradle startup script for Windows +@rem +@rem ########################################################################## + +@rem Set local scope for the variables with windows NT shell +if "%OS%"=="Windows_NT" setlocal + +set DIRNAME=%~dp0 +if "%DIRNAME%" == "" set DIRNAME=. +set APP_BASE_NAME=%~n0 +set APP_HOME=%DIRNAME% + +@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. +set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m" + +@rem Find java.exe +if defined JAVA_HOME goto findJavaFromJavaHome + +set JAVA_EXE=java.exe +%JAVA_EXE% -version >NUL 2>&1 +if "%ERRORLEVEL%" == "0" goto init + +echo. +echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. +echo. +echo Please set the JAVA_HOME variable in your environment to match the +echo location of your Java installation. + +goto fail + +:findJavaFromJavaHome +set JAVA_HOME=%JAVA_HOME:"=% +set JAVA_EXE=%JAVA_HOME%/bin/java.exe + +if exist "%JAVA_EXE%" goto init + +echo. +echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% +echo. +echo Please set the JAVA_HOME variable in your environment to match the +echo location of your Java installation. + +goto fail + +:init +@rem Get command-line arguments, handling Windows variants + +if not "%OS%" == "Windows_NT" goto win9xME_args + +:win9xME_args +@rem Slurp the command line arguments. +set CMD_LINE_ARGS= +set _SKIP=2 + +:win9xME_args_slurp +if "x%~1" == "x" goto execute + +set CMD_LINE_ARGS=%* + +:execute +@rem Setup the command line + +set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar + +@rem Execute Gradle +"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS% + +:end +@rem End local scope for the variables with windows NT shell +if "%ERRORLEVEL%"=="0" goto mainEnd + +:fail +rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of +rem the _cmd.exe /c_ return code! +if not "" == "%GRADLE_EXIT_CONSOLE%" exit 1 +exit /b 1 + +:mainEnd +if "%OS%"=="Windows_NT" endlocal + +:omega diff --git a/kotlin/diffie-hellman/src/main/kotlin/DiffieHellman.kt b/kotlin/diffie-hellman/src/main/kotlin/DiffieHellman.kt new file mode 100644 index 0000000..75338cb --- /dev/null +++ b/kotlin/diffie-hellman/src/main/kotlin/DiffieHellman.kt @@ -0,0 +1,22 @@ +import java.math.BigInteger +import java.util.* + +object DiffieHellman { + + fun privateKey(prime: BigInteger): BigInteger { + var returnVal: BigInteger + val random = Random() + do { + returnVal = BigInteger.probablePrime(random.nextInt(prime.bitLength()).coerceAtLeast(2), random) + } while (returnVal >= prime && returnVal != 0.toBigInteger()) + return returnVal + } + + fun publicKey(p: BigInteger, g: BigInteger, privKey: BigInteger): BigInteger { + return g.modPow(privKey, p) + } + + fun secret(prime: BigInteger, publicKey: BigInteger, privateKey: BigInteger): BigInteger { + return publicKey.modPow(privateKey, prime) + } +} diff --git a/kotlin/diffie-hellman/src/test/kotlin/DiffieHellmanTest.kt b/kotlin/diffie-hellman/src/test/kotlin/DiffieHellmanTest.kt new file mode 100644 index 0000000..25e5ff4 --- /dev/null +++ b/kotlin/diffie-hellman/src/test/kotlin/DiffieHellmanTest.kt @@ -0,0 +1,70 @@ +import org.junit.Test +import java.math.BigInteger +import kotlin.test.assertEquals +import kotlin.test.assertNotEquals +import kotlin.test.assertTrue + +class DiffieHellmanTest { + + @Test + fun `private key is in range from 1 to prime`() { + val prime = 23.toBigInteger() + (0..9).map { DiffieHellman.privateKey(prime) }.forEach { + assertTrue(it >= BigInteger.ONE) + assertTrue(it < prime) + } + } + + /** + * Due to the nature of randomness, there is always a chance that this test fails. + * Be sure to check the actual generated values. + */ + @Test + fun `private key is random`() { + val prime = 7919.toBigInteger() + val privateKeyA = DiffieHellman.privateKey(prime) + val privateKeyB = DiffieHellman.privateKey(prime) + + assertNotEquals(privateKeyA, privateKeyB) + } + + @Test + fun `calculate public key using private key`() { + val primeA = 23.toBigInteger() + val primeB = 5.toBigInteger() + val privateKey = 6.toBigInteger() + val expected = 8.toBigInteger() + + assertEquals(expected, DiffieHellman.publicKey(primeA, primeB, privateKey)) + } + + + @Test + fun `calculate secret using other party's public key`() { + val prime = 23.toBigInteger() + val publicKey = 19.toBigInteger() + val privateKey = 6.toBigInteger() + val expected = 2.toBigInteger() + + assertEquals(expected, DiffieHellman.secret(prime, publicKey, privateKey)) + } + + + @Test + fun `key exchange`() { + val primeA = 23.toBigInteger() + val primeB = 5.toBigInteger() + + val alicePrivateKey = DiffieHellman.privateKey(primeA) + val bobPrivateKey = DiffieHellman.privateKey(primeB) + + val alicePublicKey = DiffieHellman.publicKey(primeA, primeB, alicePrivateKey) + val bobPublicKey = DiffieHellman.publicKey(primeA, primeB, bobPrivateKey) + + val secretA = DiffieHellman.secret(primeA, bobPublicKey, alicePrivateKey) + val secretB = DiffieHellman.secret(primeA, alicePublicKey, bobPrivateKey) + + assertEquals(secretA, secretB) + } + +}