unveiled secret key的用法和样例：
例句
- Users can make their public keys freely available or place them at a key distribution centre for others to access.
用户可以让公开密钥自由使用或者把公开密钥放在可由别人存取的密钥分配中心。 - Conversely,plaintext encrypted with the private key can be decrypted only with the public key.
相反，用秘密密钥加密的普通文本只能由公开密钥解密。
