diff --git a/block/qcow.c b/block/qcow.c
index 66827d6f24..c08cdc4a7b 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -768,7 +768,7 @@ static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
     Error *local_err = NULL;
     int ret;
     BlockBackend *qcow_blk;
-    const char *encryptfmt = NULL;
+    char *encryptfmt = NULL;
     QDict *options;
     QDict *encryptopts = NULL;
     QCryptoBlockCreateOptions *crypto_opts = NULL;
@@ -793,7 +793,7 @@ static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
             goto cleanup;
         }
     } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
-        encryptfmt = "aes";
+        encryptfmt = g_strdup("aes");
     }
 
     ret = bdrv_create_file(filename, opts, &local_err);
@@ -908,6 +908,7 @@ exit:
     blk_unref(qcow_blk);
 cleanup:
     QDECREF(encryptopts);
+    g_free(encryptfmt);
     qcrypto_block_free(crypto);
     qapi_free_QCryptoBlockCreateOptions(crypto_opts);
     g_free(backing_file);
diff --git a/block/qcow2.c b/block/qcow2.c
index 90efa4477b..d7c600b5a2 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2905,7 +2905,7 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     int version;
     uint64_t refcount_bits;
     int refcount_order;
-    const char *encryptfmt = NULL;
+    char *encryptfmt = NULL;
     Error *local_err = NULL;
     int ret;
 
@@ -2916,14 +2916,14 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
     backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
     encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT);
     if (encryptfmt) {
-        if (qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT)) {
+        if (qemu_opt_get(opts, BLOCK_OPT_ENCRYPT)) {
             error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and "
                        BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive");
             ret = -EINVAL;
             goto finish;
         }
     } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
-        encryptfmt = "aes";
+        encryptfmt = g_strdup("aes");
     }
     cluster_size = qcow2_opt_get_cluster_size_del(opts, &local_err);
     if (local_err) {
@@ -2983,6 +2983,7 @@ static int qcow2_create(const char *filename, QemuOpts *opts, Error **errp)
 finish:
     g_free(backing_file);
     g_free(backing_fmt);
+    g_free(encryptfmt);
     g_free(buf);
     return ret;
 }