diff --git a/ChangeLog b/ChangeLog
index 0ffdbf7..89a9469 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,8 @@
      was creating an invalid ASN.1 tag. Found by Aryeh R. Fixes #1257.
    * Remove unused headers included in x509.c. Found by Chris Hanson and fixed
      by Brendan Shanks. Part of a fix for #992.
+   * Fix compilation error when MBEDTLS_ARC4_C is disabled and
+     MBEDTLS_CIPHER_NULL_CIPHER is enabled. Found by TrinityTonic in #1719.
 
 = mbed TLS 2.7.4 branch released 2018-06-18
 
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index d1f4efe..1c453a1 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -43,7 +43,7 @@
 #define MBEDTLS_CIPHER_MODE_WITH_PADDING
 #endif
 
-#if defined(MBEDTLS_ARC4_C)
+#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER)
 #define MBEDTLS_CIPHER_MODE_STREAM
 #endif
 
diff --git a/library/cipher.c b/library/cipher.c
index 7369f48..0d84ccf 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -56,10 +56,6 @@
 #define mbedtls_free   free
 #endif
 
-#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER)
-#define MBEDTLS_CIPHER_MODE_STREAM
-#endif
-
 /* Implementation that should never be optimized out by the compiler */
 static void mbedtls_zeroize( void *v, size_t n ) {
     volatile unsigned char *p = (unsigned char*)v; while( n-- ) *p++ = 0;