curl -H "Authorization: Bearer <Token>" https://frog-host/artifactory/api/search/checksum\?sha256\=<sha256>
curl -H "Authorization: Bearer <Token>" https://frog-host/artifactory/api/storage/{repoKey}/{filePath} \
| jq '.checksums.sha256
if you want to get the sha256 for docker image the resource you need is "manifest.json"
curl -H "Authorization: Bearer <Token>" https://frog-host/artifactory/api/storage/{repoKey}/{group}/{artifact}/{version}/manifest.json \
| jq '.checksums.sha256