diff --git a/pgpainless-core/src/main/java/org/pgpainless/util/DateUtil.java b/pgpainless-core/src/main/java/org/pgpainless/util/DateUtil.java
deleted file mode 100644
index f56020d4..00000000
--- a/pgpainless-core/src/main/java/org/pgpainless/util/DateUtil.java
+++ /dev/null
@@ -1,75 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package org.pgpainless.util;
-
-import javax.annotation.Nonnull;
-import java.text.ParseException;
-import java.text.SimpleDateFormat;
-import java.util.Date;
-import java.util.TimeZone;
-
-public final class DateUtil {
-
-    private DateUtil() {
-
-    }
-
-    // Java's SimpleDateFormat is not thread-safe, therefore we return a new instance on every invocation.
-    @Nonnull
-    public static SimpleDateFormat getParser() {
-        SimpleDateFormat parser = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
-        parser.setTimeZone(TimeZone.getTimeZone("UTC"));
-        return parser;
-    }
-
-    /**
-     * Parse a UTC timestamp into a date.
-     *
-     * @param dateString timestamp
-     * @return date
-     */
-    @Nonnull
-    public static Date parseUTCDate(@Nonnull String dateString) {
-        try {
-            return getParser().parse(dateString);
-        } catch (ParseException e) {
-            throw new IllegalArgumentException("Malformed UTC timestamp: " + dateString, e);
-        }
-    }
-
-    /**
-     * Format a date as UTC timestamp.
-     *
-     * @param date date
-     * @return timestamp
-     */
-    @Nonnull
-    public static String formatUTCDate(Date date) {
-        return getParser().format(date);
-    }
-
-    /**
-     * Floor a date down to seconds precision.
-     * @param date date
-     * @return floored date
-     */
-    @Nonnull
-    public static Date toSecondsPrecision(@Nonnull Date date) {
-        long millis = date.getTime();
-        long seconds = millis / 1000;
-        long floored = seconds * 1000;
-        return new Date(floored);
-    }
-
-    /**
-     * Return the current date "floored" to UTC precision.
-     *
-     * @return now
-     */
-    @Nonnull
-    public static Date now() {
-        return toSecondsPrecision(new Date());
-    }
-}
diff --git a/pgpainless-core/src/main/kotlin/openpgp/DateExtensions.kt b/pgpainless-core/src/main/kotlin/openpgp/DateExtensions.kt
index db98fb44..5972cd3a 100644
--- a/pgpainless-core/src/main/kotlin/openpgp/DateExtensions.kt
+++ b/pgpainless-core/src/main/kotlin/openpgp/DateExtensions.kt
@@ -4,20 +4,53 @@
 
 package openpgp
 
+import java.text.ParseException
+import java.text.SimpleDateFormat
 import java.util.*
 
-    /**
-     * Return a new date which represents this date plus the given amount of seconds added.
-     *
-     * Since '0' is a special date value in the OpenPGP specification
-     * (e.g. '0' means no expiration for expiration dates), this method will return 'null' if seconds is 0.
-     *
-     * @param date date
-     * @param seconds number of seconds to be added
-     * @return date plus seconds or null if seconds is '0'
-     */
-    fun Date.plusSeconds(seconds: Long): Date? {
-        require(Long.MAX_VALUE - time > seconds) { "Adding $seconds seconds to this date would cause time to overflow." }
-        return if (seconds == 0L) null
-        else Date(this.time + 1000 * seconds)
+/**
+ * Return a new date which represents this date plus the given amount of seconds added.
+ *
+ * Since '0' is a special date value in the OpenPGP specification
+ * (e.g. '0' means no expiration for expiration dates), this method will return 'null' if seconds is 0.
+ *
+ * @param date date
+ * @param seconds number of seconds to be added
+ * @return date plus seconds or null if seconds is '0'
+ */
+fun Date.plusSeconds(seconds: Long): Date? {
+    require(Long.MAX_VALUE - time > seconds) { "Adding $seconds seconds to this date would cause time to overflow." }
+    return if (seconds == 0L) null
+    else Date(this.time + 1000 * seconds)
+}
+
+/**
+ * Return a new [Date] instance with this instance's time floored down to seconds precision.
+ */
+fun Date.toSecondsPrecision(): Date {
+    return Date((time / 1000) * 1000)
+}
+
+internal val parser: SimpleDateFormat
+    // Java's SimpleDateFormat is not thread-safe, therefore we return a new instance on every invocation.
+    get() = SimpleDateFormat("yyyy-MM-dd HH:mm:ss z")
+            .apply { timeZone = TimeZone.getTimeZone("UTC") }
+
+/**
+ * Format a date as UTC timestamp.
+ *
+ * @return timestamp
+ */
+fun Date.formatUTC(): String = parser.format(this)
+
+/**
+ * Parse a UTC timestamp into a date.
+ * @return date
+ */
+fun String.parseUTC(): Date {
+    return try {
+        parser.parse(this)
+    } catch (e : ParseException) {
+        throw IllegalArgumentException("Malformed UTC timestamp: $this", e)
     }
+}
diff --git a/pgpainless-core/src/main/kotlin/org/pgpainless/util/DateUtil.kt b/pgpainless-core/src/main/kotlin/org/pgpainless/util/DateUtil.kt
new file mode 100644
index 00000000..de2052d6
--- /dev/null
+++ b/pgpainless-core/src/main/kotlin/org/pgpainless/util/DateUtil.kt
@@ -0,0 +1,50 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.util
+
+import openpgp.formatUTC
+import openpgp.parseUTC
+import openpgp.toSecondsPrecision
+import java.util.*
+
+class DateUtil {
+
+    companion object {
+
+        /**
+         * Parse a UTC timestamp into a date.
+         *
+         * @param dateString timestamp
+         * @return date
+         */
+        @JvmStatic
+        fun parseUTCDate(dateString: String): Date = dateString.parseUTC()
+
+        /**
+         * Format a date as UTC timestamp.
+         *
+         * @param date date
+         * @return timestamp
+         */
+        @JvmStatic
+        fun formatUTCDate(date: Date): String = date.formatUTC()
+
+        /**
+         * Floor a date down to seconds precision.
+         * @param date date
+         * @return floored date
+         */
+        @JvmStatic
+        fun toSecondsPrecision(date: Date): Date = date.toSecondsPrecision()
+
+        /**
+         * Return the current date "floored" to UTC precision.
+         *
+         * @return now
+         */
+        @JvmStatic
+        fun now() = toSecondsPrecision(Date())
+    }
+}
\ No newline at end of file