I found https://defuse.ca/pastebin.htm to be pretty useful and working well.
This pastebin encrypts your post with a 128 bit equivalent random code
which is included in the paste URL. The URL code is hashed using
SHA256 into a key for AES-256 in CBC (Cipher Block Chaining) mode. The
only way anyone will see your paste is if they have the URL. So only
share the paste URL with people you trust, and your data will be 100%
private. We've also setup a robots.txt file telling Google and other
search engines not to index the contents of the pastebin. If we get a
court order to decrypt a post, we will not be able to comply.
You also have the option of encrypting your text with client-side
encryption. This is much more secure because the encryption and
never get the chance to see the unencrypted data nor the password used
to encrypt it. When you use client-side encryption, your password gets
hashed with SHA256 into a 256 bit key for the AES block cipher, which
is used to encrypt the text in CBC mode. A random 256 bit salt and a
random initialization vector are provided by our server's CSPRNG
(Cryptographically Secure Pseudorandom Number Generator).
The data is always sent to Defuse Cyber-Security through a secure,
AES-256 encrypted, SSL/TLS connection.