diff --git a/fuzzers/fuzz_group_decrypt.cpp b/fuzzers/fuzz_group_decrypt.cpp
index 03b7bc4..e32c0ae 100644
--- a/fuzzers/fuzz_group_decrypt.cpp
+++ b/fuzzers/fuzz_group_decrypt.cpp
@@ -2,6 +2,18 @@
 
 #include "fuzzing.hh"
 
+#ifndef __AFL_FUZZ_TESTCASE_LEN
+  ssize_t fuzz_len;
+  #define __AFL_FUZZ_TESTCASE_LEN fuzz_len
+  unsigned char fuzz_buf[1024000];
+  #define __AFL_FUZZ_TESTCASE_BUF fuzz_buf
+  #define __AFL_FUZZ_INIT() void sync(void);
+  #define __AFL_LOOP(x) ((fuzz_len = read(0, fuzz_buf, sizeof(fuzz_buf))) > 0 ? 1 : 0)
+  #define __AFL_INIT() sync()
+#endif
+
+__AFL_FUZZ_INIT();
+
 int main(int argc, const char *argv[]) {
     if (argc <= 2) {
         const char * message = "Usage: decrypt <pickle_key> <group_session>\n";
@@ -22,15 +34,6 @@ int main(int argc, const char *argv[]) {
         "Error reading session file", read_file(session_fd, &session_buffer)
     );
 
-    int message_fd = STDIN_FILENO;
-    uint8_t * message_buffer;
-    ssize_t message_length = check_errno(
-        "Error reading message file", read_file(message_fd, &message_buffer)
-    );
-
-    uint8_t * tmp_buffer = (uint8_t *) malloc(message_length);
-    memcpy(tmp_buffer, message_buffer, message_length);
-
     uint8_t session_memory[olm_inbound_group_session_size()];
     OlmInboundGroupSession * session = olm_inbound_group_session(session_memory);
     check_error(
@@ -42,32 +45,54 @@ int main(int argc, const char *argv[]) {
         )
     );
 
-    size_t max_length = check_error(
-        olm_inbound_group_session_last_error,
-        session,
-        "Error getting plaintext length",
-        olm_group_decrypt_max_plaintext_length(
-            session, tmp_buffer, message_length
-        )
-    );
+#ifdef __AFL_HAVE_MANUAL_CONTROL
+    __AFL_INIT();
+#endif
 
-    uint8_t plaintext[max_length];
+    size_t test_case_buf_len = 1024;
+    uint8_t * message_buffer = (uint8_t *) malloc(test_case_buf_len);
+    uint8_t * tmp_buffer = (uint8_t *) malloc(test_case_buf_len);
 
-    uint32_t ratchet_index;
+    while (__AFL_LOOP(10000)) {
+        size_t message_length = __AFL_FUZZ_TESTCASE_LEN;
 
-    size_t length = check_error(
-        olm_inbound_group_session_last_error,
-        session,
-        "Error decrypting message",
-        olm_group_decrypt(
+        if (message_length > test_case_buf_len) {
+            message_buffer = (uint8_t *)realloc(message_buffer, message_length);
+            tmp_buffer = (uint8_t *)realloc(tmp_buffer, message_length);
+
+            if (!message_buffer || !tmp_buffer) return 1;
+        }
+
+        memcpy(message_buffer, __AFL_FUZZ_TESTCASE_BUF, message_length);
+        memcpy(tmp_buffer, message_buffer, message_length);
+
+        size_t max_length = check_error(
+            olm_inbound_group_session_last_error,
             session,
-            message_buffer, message_length,
-            plaintext, max_length, &ratchet_index
-        )
-    );
+            "Error getting plaintext length",
+            olm_group_decrypt_max_plaintext_length(
+                session, tmp_buffer, message_length
+            )
+        );
 
-    (void)write(STDOUT_FILENO, plaintext, length);
-    (void)write(STDOUT_FILENO, "\n", 1);
+        uint8_t plaintext[max_length];
+
+        uint32_t ratchet_index;
+
+        size_t length = check_error(
+            olm_inbound_group_session_last_error,
+            session,
+            "Error decrypting message",
+            olm_group_decrypt(
+                session,
+                message_buffer, message_length,
+                plaintext, max_length, &ratchet_index
+            )
+        );
+
+        (void)write(STDOUT_FILENO, plaintext, length);
+        (void)write(STDOUT_FILENO, "\n", 1);
+    }
 
     free(session_buffer);
     free(message_buffer);