diff --git a/libraries/sysiolib/core/sysio/crypto.hpp b/libraries/sysiolib/core/sysio/crypto.hpp
index d605a37c7..42e73bb4d 100644
--- a/libraries/sysiolib/core/sysio/crypto.hpp
+++ b/libraries/sysiolib/core/sysio/crypto.hpp
@@ -248,12 +248,13 @@ namespace sysio {
 
    /**
     * SYSIO ED signature data
-    * 
-    * Fixed size representation of a ED25519 signature
-    * 
+    *
+    * Fixed size representation of a ED25519 signature (96 bytes = 32 pubkey + 64 sig)
+    * The public key is embedded at [0..31], the signature at [32..95].
+    *
     * @ingroup signature
     */
-   using ed_signature = std::array<uint8_t, 64>;
+   using ed_signature = std::array<uint8_t, 96>;
 
    /**
     * SYSIO BLS signature data