diff --git a/src/crypto.c b/src/crypto.c
index 3f516940..c5bf6fe1 100644
--- a/src/crypto.c
+++ b/src/crypto.c
@@ -321,9 +321,9 @@ static bool s2v(struct l_checksum *cmac, struct iovec *iov, size_t iov_len,
 /*
  * RFC 5297 Section 2.6 - SIV Encrypt
  */
-bool aes_siv_encrypt(const uint8_t *key, size_t key_len, const uint8_t *in,
+bool aes_siv_encrypt(const void *key, size_t key_len, const void *in,
 			size_t in_len, struct iovec *ad, size_t num_ad,
-			uint8_t *out)
+			void *out)
 {
 	struct l_checksum *cmac;
 	struct l_cipher *ctr;
@@ -374,9 +374,9 @@ free_ctr:
 	return false;
 }
 
-bool aes_siv_decrypt(const uint8_t *key, size_t key_len, const uint8_t *in,
+bool aes_siv_decrypt(const void *key, size_t key_len, const void *in,
 			size_t in_len, struct iovec *ad, size_t num_ad,
-			uint8_t *out)
+			void *out)
 {
 	struct l_checksum *cmac;
 	struct l_cipher *ctr;
diff --git a/src/crypto.h b/src/crypto.h
index d359da61..eb48fe5b 100644
--- a/src/crypto.h
+++ b/src/crypto.h
@@ -83,12 +83,12 @@ bool aes_wrap(const uint8_t *kek, const uint8_t *in, size_t len, uint8_t *out);
 bool arc4_skip(const uint8_t *key, size_t key_len, size_t skip,
 		const uint8_t *in, size_t len, uint8_t *out);
 
-bool aes_siv_encrypt(const uint8_t *key, size_t key_len, const uint8_t *in,
+bool aes_siv_encrypt(const void *key, size_t key_len, const void *in,
 			size_t in_len, struct iovec *ad, size_t num_ad,
-			uint8_t *out);
-bool aes_siv_decrypt(const uint8_t *key, size_t key_len, const uint8_t *in,
+			void *out);
+bool aes_siv_decrypt(const void *key, size_t key_len, const void *in,
 			size_t in_len, struct iovec *ad, size_t num_ad,
-			uint8_t *out);
+			void *out);
 
 int crypto_cipher_key_len(enum crypto_cipher cipher);
 int crypto_cipher_tk_bits(enum crypto_cipher cipher);