diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 072ebbe..45b991b 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -191,6 +191,7 @@
 
 /* Elliptic Curve Groups (ECDHE) */
 #define MBEDTLS_SSL_IANA_TLS_GROUP_NONE               0
+#define MBEDTLS_SSL_IANA_TLS_GROUP_SECT163K1     0x0001 /* RFC 4492 */
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192K1     0x0012
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP192R1     0x0013
 #define MBEDTLS_SSL_IANA_TLS_GROUP_SECP224K1     0x0014