diff --git a/include/gmssl/gcm.h b/include/gmssl/gcm.h
deleted file mode 100644
index c2aae9f0..00000000
--- a/include/gmssl/gcm.h
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- *  Copyright 2014-2024 The GmSSL Project. All Rights Reserved.
- *
- *  Licensed under the Apache License, Version 2.0 (the License); you may
- *  not use this file except in compliance with the License.
- *
- *  http://www.apache.org/licenses/LICENSE-2.0
- */
-
-#ifndef GMSSL_GCM_H
-#define GMSSL_GCM_H
-
-
-#include <stdlib.h>
-#include <stdint.h>
-#include <string.h>
-#include <gmssl/ghash.h>
-#include <gmssl/block_cipher.h>
-
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#define GCM_IV_MIN_SIZE		1
-#define GCM_IV_MAX_SIZE		((uint64_t)(1 << (64-3)))
-#define GCM_IV_DEFAULT_BITS	96
-#define GCM_IV_DEFAULT_SIZE	12
-
-#define GCM_MIN_AAD_SIZE	0
-#define GCM_MAX_AAD_SIZE	((uint64_t)(1 << (64-3)))
-
-#define GCM_MIN_PLAINTEXT_SIZE	0
-#define GCM_MAX_PLAINTEXT_SIZE	((((uint64_t)1 << 39) - 256) >> 3)
-
-
-#define GCM_IS_LITTLE_ENDIAN 1
-
-
-int gcm_encrypt(const BLOCK_CIPHER_KEY *key, const uint8_t *iv, size_t ivlen,
-	const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen,
-	uint8_t *out, size_t taglen, uint8_t *tag);
-
-int gcm_decrypt(const BLOCK_CIPHER_KEY *key, const uint8_t *iv, size_t ivlen,
-	const uint8_t *aad, size_t aadlen, const uint8_t *in, size_t inlen,
-	const uint8_t *tag, size_t taglen, uint8_t *out);
-
-
-#ifdef __cplusplus
-}
-#endif
-#endif
diff --git a/src/aes_modes.c b/src/aes_modes.c
index 89e5a6e9..7a521837 100644
--- a/src/aes_modes.c
+++ b/src/aes_modes.c
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2014-2022 The GmSSL Project. All Rights Reserved.
+ *  Copyright 2014-2024 The GmSSL Project. All Rights Reserved.
  *
  *  Licensed under the Apache License, Version 2.0 (the License); you may
  *  not use this file except in compliance with the License.
@@ -13,9 +13,9 @@
 #include <string.h>
 #include <stdlib.h>
 #include <gmssl/aes.h>
-#include <gmssl/gcm.h>
-#include <gmssl/error.h>
 #include <gmssl/mem.h>
+#include <gmssl/ghash.h>
+#include <gmssl/error.h>
 
 
 void aes_cbc_encrypt(const AES_KEY *key, const uint8_t iv[16],
@@ -149,16 +149,8 @@ int aes_gcm_encrypt(const AES_KEY *key, const uint8_t *iv, size_t ivlen,
 
 	aes_encrypt(key, Y, T);
 
-	while (left) {
-		uint8_t block[16];
-		size_t len = left < 16 ? left : 16;
-		ctr_incr(Y);
-		aes_encrypt(key, Y, block);
-		gmssl_memxor(pout, pin, block, len);
-		pin += len;
-		pout += len;
-		left -= len;
-	}
+	ctr_incr(Y);
+	aes_ctr_encrypt(key, Y, in, inlen, out);
 
 	ghash(H, aad, aadlen, out, inlen, H);
 	gmssl_memxor(tag, T, H, taglen);
@@ -194,15 +186,8 @@ int aes_gcm_decrypt(const AES_KEY *key, const uint8_t *iv, size_t ivlen,
 		return -1;
 	}
 
-	while (left) {
-		uint8_t block[16];
-		size_t len = left < 16 ? left : 16;
-		ctr_incr(Y);
-		aes_encrypt(key, Y, block);
-		gmssl_memxor(pout, pin, block, len);
-		pin += len;
-		pout += len;
-		left -= len;
-	}
+	ctr_incr(Y);
+	aes_ctr_encrypt(key, Y, in, inlen, out);
+
 	return 1;
 }
diff --git a/src/sm4_gcm.c b/src/sm4_gcm.c
index a86d3e29..880d2dc4 100644
--- a/src/sm4_gcm.c
+++ b/src/sm4_gcm.c
@@ -10,7 +10,7 @@
 
 #include <gmssl/sm4.h>
 #include <gmssl/mem.h>
-#include <gmssl/gcm.h>
+#include <gmssl/ghash.h>
 #include <gmssl/error.h>