message: Avoid the US_ASCII charset.
diff: package com.google.crypto.tink.mac;
  -import static java.nio.charset.StandardCharsets.US_ASCII;
  import com.google.crypto.tink.AccessesPartialKey;
  import com.google.crypto.tink.SecretKeyAccess;
  @@ -35,6 +34,7 @@ import com.google.crypto.tink.util.SecretBytes;
  import com.google.protobuf.ByteString;
  import com.google.protobuf.ExtensionRegistryLite;
  import com.google.protobuf.InvalidProtocolBufferException;
  +import java.io.UnsupportedEncodingException;
  import java.security.GeneralSecurityException;
  import javax.annotation.Nullable;
  @@ -45,7 +45,18 @@ import javax.annotation.Nullable;
  @SuppressWarnings("UnnecessarilyFullyQualified") // Fully specifying proto types is more readable
  final class AesCmacProtoSerialization {
  private static final String TYPE_URL = "type.googleapis.com/google.crypto.tink.AesCmacKey";
  - private static final Bytes TYPE_URL_BYTES = Bytes.copyFrom(TYPE_URL.getBytes(US_ASCII));
  +
  + // TODO(tholenst): move this to a Tink-internal utility function and avoid getBytes completely
  + // (since it ignores non-ascii anyhow) and make errors into an InternalTinkError.
  + private static final Bytes toBytesAscii(String s) {
  + try {
  + return Bytes.copyFrom(s.getBytes("ASCII"));
  + } catch (UnsupportedEncodingException e) {
  + throw new IllegalArgumentException(e);
  + }
  + }
  +
  + private static final Bytes TYPE_URL_BYTES = toBytesAscii(TYPE_URL);
  private static final ParametersSerializer<AesCmacParameters, ProtoParametersSerialization>
  PARAMETERS_SERIALIZER =
  ParametersSerializer.create(
  