NULL ciphers

Detlef Vollmann dv at
Thu Aug 13 18:19:10 UTC 2020


with the following commands:

openssl s_server -accept 18010 -cert srv.crt -key test.key \
-CAfile testca.crt -debug -cipher 'NULL-SHA256' -dtls1_2

openssl s_client -connect localhost:18010 -cert clnt.crt \
  -key test.key -CAfile testca.crt -debug \
  -cipher 'COMPLEMENTOFALL:eNULL' -dtls1_2

NULL ciphers work fine with OpenSSL 1.0.2g.

With OpenSSL 1.1.1g the handshake fails on the server side with
140295725053248:error:14102438:SSL routines:dtls1_read_bytes:tlsv1 \
alert internal error:../ssl/record/rec_layer_d1.c:611:SSL alert number \

Even on OpenSSL 1.1.1g 'openssl ciphers -v  NULL' lists NULL-SHA256.

I'm only using s_server and s_client as tests, but I have the same
problem in my application if I use
  SSL_CTX_set_cipher_list(sslCtx, "NULL-SHA256");

What can I do to get NULL ciphers for no encryption working?


More information about the openssl-users mailing list