diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/auth/HttpBasicAuth.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/auth/HttpBasicAuth.kt.mustache
index 0e3dba003ef0..c18b30352f05 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/auth/HttpBasicAuth.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-ktor/auth/HttpBasicAuth.kt.mustache
@@ -1,6 +1,6 @@
 package {{packageName}}.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 {{^nonPublicApi}}{{#explicitApi}}public {{/explicitApi}}{{/nonPublicApi}}class HttpBasicAuth : Authentication {
     {{^nonPublicApi}}{{#explicitApi}}public {{/explicitApi}}{{/nonPublicApi}}var username: String? = null
@@ -9,7 +9,7 @@ import io.ktor.util.encodeBase64
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/auth/HttpBasicAuth.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/auth/HttpBasicAuth.kt.mustache
index 0e3dba003ef0..c18b30352f05 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/auth/HttpBasicAuth.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/multiplatform/auth/HttpBasicAuth.kt.mustache
@@ -1,6 +1,6 @@
 package {{packageName}}.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 {{^nonPublicApi}}{{#explicitApi}}public {{/explicitApi}}{{/nonPublicApi}}class HttpBasicAuth : Authentication {
     {{^nonPublicApi}}{{#explicitApi}}public {{/explicitApi}}{{/nonPublicApi}}var username: String? = null
@@ -9,7 +9,7 @@ import io.ktor.util.encodeBase64
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-array-simple-string-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-array-simple-string-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-array-simple-string-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-array-simple-string-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-bigdecimal-default-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-bigdecimal-default-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-bigdecimal-default-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-bigdecimal-default-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-default-values-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-enum-integers-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-enum-integers-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-enum-integers-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-enum-integers-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-jvm-ktor-gson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-jvm-ktor-jackson/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-jvm-ktor-kotlinx_serialization/src/main/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-multiplatform-allOf-discriminator/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-multiplatform-allOf-discriminator/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-multiplatform-allOf-discriminator/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-multiplatform-allOf-discriminator/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-multiplatform-kotlinx-datetime/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }
diff --git a/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt b/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
index 7c4761bbd6f7..b4aecdc99658 100644
--- a/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
+++ b/samples/client/petstore/kotlin-multiplatform/src/commonMain/kotlin/org/openapitools/client/auth/HttpBasicAuth.kt
@@ -1,6 +1,6 @@
 package org.openapitools.client.auth
 
-import io.ktor.util.encodeBase64
+import kotlin.io.encoding.Base64
 
 class HttpBasicAuth : Authentication {
     var username: String? = null
@@ -9,7 +9,7 @@ class HttpBasicAuth : Authentication {
     override fun apply(query: MutableMap<String, List<String>>, headers: MutableMap<String, String>) {
         if (username == null && password == null) return
         val str = (username ?: "") + ":" + (password ?: "")
-        val auth = str.encodeBase64()
+        val auth = Base64.encode(str.encodeToByteArray())
         headers["Authorization"] = "Basic $auth"
     }
 }