tinyca binary package in Ubuntu Bionic s390x

 TinyCA is a program with a simple graphical user interface that makes
 managing a small CA (Certification Authority) easy. TinyCA works as
 a frontend for openssl and can deal with several independent CAs.
 .
 With TinyCA you can create and manage x509 and S/MIME server and
 client certificates. You can choose between RSA and DSA keys, as
 well as between different digest algorithms.
 .
 The certificates can be exported as PEM, DER, TXT and PKCS#12 or as a
 convenient archive containing both key and certificate. Certificates
 can be revoked by adding them to a certificate revocation list.

Source package