diff --git a/crypto/ecdsa/ecs_asn1.c b/crypto/ecdsa/ecs_asn1.c
index f68081d42c..0b2baf7219 100644
--- a/crypto/ecdsa/ecs_asn1.c
+++ b/crypto/ecdsa/ecs_asn1.c
@@ -86,7 +86,7 @@ DECLARE_ASN1_ENCODE_FUNCTIONS_const(X9_62_CURVE, X9_62_CURVE)
 IMPLEMENT_ASN1_FUNCTIONS_const(X9_62_CURVE)
 
 ASN1_SEQUENCE(X9_62_EC_PARAMETERS) = {
-	ASN1_OPT(X9_62_EC_PARAMETERS, version, ASN1_INTEGER),
+	ASN1_SIMPLE(X9_62_EC_PARAMETERS, version, ASN1_INTEGER),
 	ASN1_SIMPLE(X9_62_EC_PARAMETERS, fieldID, X9_62_FIELDID),
 	ASN1_SIMPLE(X9_62_EC_PARAMETERS, curve, X9_62_CURVE),
 	ASN1_SIMPLE(X9_62_EC_PARAMETERS, base, ASN1_OCTET_STRING),