diff --git a/include/crypto/chacha20poly1305.h b/include/crypto/chacha20poly1305.h
index d2ac3ff7dc1e..0f71b037702d 100644
--- a/include/crypto/chacha20poly1305.h
+++ b/include/crypto/chacha20poly1305.h
@@ -18,32 +18,33 @@ enum chacha20poly1305_lengths {
 void chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
 			      const u8 *ad, const size_t ad_len,
 			      const u64 nonce,
-			      const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+			      const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
 
 bool __must_check
 chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
 			 const u8 *ad, const size_t ad_len, const u64 nonce,
-			 const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+			 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
 
 void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
 			       const u8 *ad, const size_t ad_len,
-			       const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
-			       const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+			       const u8 nonce[at_least XCHACHA20POLY1305_NONCE_SIZE],
+			       const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
 
 bool __must_check xchacha20poly1305_decrypt(
-	u8 *dst, const u8 *src, const size_t src_len, const u8 *ad,
-	const size_t ad_len, const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
-	const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+	u8 *dst, const u8 *src, const size_t src_len,
+	const u8 *ad, const size_t ad_len,
+	const u8 nonce[at_least XCHACHA20POLY1305_NONCE_SIZE],
+	const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
 
 bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
 					 const u8 *ad, const size_t ad_len,
 					 const u64 nonce,
-					 const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+					 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
 
 bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
 					 const u8 *ad, const size_t ad_len,
 					 const u64 nonce,
-					 const u8 key[CHACHA20POLY1305_KEY_SIZE]);
+					 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE]);
 
 bool chacha20poly1305_selftest(void);
 
diff --git a/lib/crypto/chacha20poly1305.c b/lib/crypto/chacha20poly1305.c
index 0b49d6aedefd..212ce33562af 100644
--- a/lib/crypto/chacha20poly1305.c
+++ b/lib/crypto/chacha20poly1305.c
@@ -89,7 +89,7 @@ __chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
 void chacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
 			      const u8 *ad, const size_t ad_len,
 			      const u64 nonce,
-			      const u8 key[CHACHA20POLY1305_KEY_SIZE])
+			      const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
 {
 	struct chacha_state chacha_state;
 	u32 k[CHACHA_KEY_WORDS];
@@ -111,8 +111,8 @@ EXPORT_SYMBOL(chacha20poly1305_encrypt);
 
 void xchacha20poly1305_encrypt(u8 *dst, const u8 *src, const size_t src_len,
 			       const u8 *ad, const size_t ad_len,
-			       const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
-			       const u8 key[CHACHA20POLY1305_KEY_SIZE])
+			       const u8 nonce[at_least XCHACHA20POLY1305_NONCE_SIZE],
+			       const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
 {
 	struct chacha_state chacha_state;
 
@@ -170,7 +170,7 @@ __chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
 bool chacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
 			      const u8 *ad, const size_t ad_len,
 			      const u64 nonce,
-			      const u8 key[CHACHA20POLY1305_KEY_SIZE])
+			      const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
 {
 	struct chacha_state chacha_state;
 	u32 k[CHACHA_KEY_WORDS];
@@ -195,8 +195,8 @@ EXPORT_SYMBOL(chacha20poly1305_decrypt);
 
 bool xchacha20poly1305_decrypt(u8 *dst, const u8 *src, const size_t src_len,
 			       const u8 *ad, const size_t ad_len,
-			       const u8 nonce[XCHACHA20POLY1305_NONCE_SIZE],
-			       const u8 key[CHACHA20POLY1305_KEY_SIZE])
+			       const u8 nonce[at_least XCHACHA20POLY1305_NONCE_SIZE],
+			       const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
 {
 	struct chacha_state chacha_state;
 
@@ -211,7 +211,7 @@ bool chacha20poly1305_crypt_sg_inplace(struct scatterlist *src,
 				       const size_t src_len,
 				       const u8 *ad, const size_t ad_len,
 				       const u64 nonce,
-				       const u8 key[CHACHA20POLY1305_KEY_SIZE],
+				       const u8 key[at_least CHACHA20POLY1305_KEY_SIZE],
 				       int encrypt)
 {
 	const u8 *pad0 = page_address(ZERO_PAGE(0));
@@ -335,7 +335,7 @@ bool chacha20poly1305_crypt_sg_inplace(struct scatterlist *src,
 bool chacha20poly1305_encrypt_sg_inplace(struct scatterlist *src, size_t src_len,
 					 const u8 *ad, const size_t ad_len,
 					 const u64 nonce,
-					 const u8 key[CHACHA20POLY1305_KEY_SIZE])
+					 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
 {
 	return chacha20poly1305_crypt_sg_inplace(src, src_len, ad, ad_len,
 						 nonce, key, 1);
@@ -345,7 +345,7 @@ EXPORT_SYMBOL(chacha20poly1305_encrypt_sg_inplace);
 bool chacha20poly1305_decrypt_sg_inplace(struct scatterlist *src, size_t src_len,
 					 const u8 *ad, const size_t ad_len,
 					 const u64 nonce,
-					 const u8 key[CHACHA20POLY1305_KEY_SIZE])
+					 const u8 key[at_least CHACHA20POLY1305_KEY_SIZE])
 {
 	if (unlikely(src_len < POLY1305_DIGEST_SIZE))
 		return false;