diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/gcp/CanonicalRequestSigner.java b/service/src/main/java/org/whispersystems/textsecuregcm/gcp/CanonicalRequestSigner.java
index 4ad6e3e9f..72e1fabf2 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/gcp/CanonicalRequestSigner.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/gcp/CanonicalRequestSigner.java
@@ -76,7 +76,7 @@ public class CanonicalRequestSigner {
     if (matcher.matches()) {
       try {
         final KeyFactory keyFactory = KeyFactory.getInstance("RSA");
-        final PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.getDecoder().decode(matcher.group(1)));
+        final PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(Base64.getMimeDecoder().decode(matcher.group(1)));
         final PrivateKey key = keyFactory.generatePrivate(keySpec);
 
         testKeyIsValidForSigning(key);
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AttachmentControllerTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AttachmentControllerTest.java
index 40fcce0ff..d539cfacd 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AttachmentControllerTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/AttachmentControllerTest.java
@@ -64,7 +64,7 @@ public class AttachmentControllerTest {
       final KeyPair           keyPair          = keyPairGenerator.generateKeyPair();
 
       RSA_PRIVATE_KEY_PEM = "-----BEGIN PRIVATE KEY-----\n" +
-          Base64.getEncoder().encodeToString(keyPair.getPrivate().getEncoded()) + "\n" +
+          Base64.getMimeEncoder().encodeToString(keyPair.getPrivate().getEncoded()) + "\n" +
           "-----END PRIVATE KEY-----";
     } catch (NoSuchAlgorithmException e) {
       throw new AssertionError(e);