First write your credentials map to ~/.lein/credentials.clj like so:
{#"blueant" {:password "locative1"}
#"https://repo.clojars.org"
{:username "milgrim" :password "CLOJARS_677eb77a08974e2797bbd17a402464e5cd0f987689487633895e649b312e"}
"s3p://s3-repo-bucket/releases"
{:username "AKIAIN..." :passphrase "1TChrGK4s..."}}When storing credentials for Clojars, it's recommended to generate a deploy token per machine and store that instead rather than having a single deploy token in order to limit the scope of the damage if the credential is leaked.
Then encrypt it with gpg:
$ gpg --default-recipient-self -e \
~/.lein/credentials.clj > ~/.lein/credentials.clj.gpg