Were you looking for something in particular? For handling passwords or?
The stdlib has some via Crypto - Crystal 1.12.2, and also openssl via OpenSSL::Cipher - Crystal 1.12.2
shards.info essentially scrapes GH, could also checkout Cryptography on Shardbox which might have some additional ones as well as GitHub - veelenga/awesome-crystal: 💎 A collection of awesome Crystal libraries, tools, frameworks and software.