Awa.CipherSourcetype cipher_key = | Plaintext_key| Aes_ctr_key of Mirage_crypto.Cipher_block.AES.CTR.key
* Mirage_crypto.Cipher_block.AES.CTR.ctr| Aes_cbc_key of Mirage_crypto.Cipher_block.AES.CBC.key * Cstruct.t| Chacha20_poly1305_key of Mirage_crypto.Chacha20.key
* Mirage_crypto.Chacha20.key