Just experimenting…

$ echo -n "https://twtxt.net/user/prologic/twtxt.txt\n2020-07-18T12:39:52Z\nHello World! 😊" | sha256sum | base64 | tr -d '=' | tail -c 12
NWY4MSAgLQo

$ echo -n "https://twtxt.net/user/prologic/twtxt.txt\n2020-07-18T12:39:52Z\nHello World! 😊" | sha256sum | base32 | tr -d '=' | tr 'A-Z' 'a-z' | tail -c 12
tdqmjaeawqu

$ echo -n "https://twtxt.net/user/prologic/twtxt.txt\n2020-07-18T12:39:52Z\nHello World! 😊" | sha1sum | head -c 11
87fd9b0ae4e