auth_tag_len=

        # OpenSSL::Cipher.auth_tag_len=

(from ruby core)
### Implementation from Cipher
---
    cipher.auth_tag_len = Integer -> Integer

---

Sets the length of the authentication tag to be generated or to be given
for AEAD ciphers that requires it as in input parameter. Note that not
all AEAD ciphers support this method.

In OCB mode, the length must be supplied both when encrypting and when
decrypting, and must be before specifying an IV.