Create unique contraint for encrypted or hashed column

[therockstorm]

I want to create a unique constraint on an encrypted column, but since it's :binary (which gets stored as bytea in Postgres), the unique index doesn't work as expected. I followed the _hash instructions, but that value is stored as :binary too, so has the same limitation. Am I'm missing something or is this functionality not supported? Is there a way to store the value as a base64 string instead of binary?