diff --git a/crypto/sha512.c b/crypto/sha512.c
index 2dfe7f1..15eab9d 100644
--- a/crypto/sha512.c
+++ b/crypto/sha512.c
@@ -24,7 +24,7 @@
 
 #define SHA384_DIGEST_SIZE 48
 #define SHA512_DIGEST_SIZE 64
-#define SHA384_HMAC_BLOCK_SIZE  96
+#define SHA384_HMAC_BLOCK_SIZE 128
 #define SHA512_HMAC_BLOCK_SIZE 128
 
 struct sha512_ctx {