AF
Ash Framework•2mo ago
Jechol

🔐 AshFeistelCipher - Encrypted Integer IDs for Ash Resources

Sequential IDs (1, 2, 3...) leak business information. AshFeistelCipher provides a declarative DSL to encrypt integer IDs using Feistel cipher, transforming sequential integers into non-sequential, unpredictable values automatically via database triggers. Key Features ✅ Secure IDs without UUIDs - Hide sequential patterns while keeping efficient integer IDs (bigint) ✅ Automatic encryption - Database triggers handle encryption transparently
✅ Collision-free - Deterministic one-to-one mapping ✅ Declarative DSL - Clean, Ash-idiomatic syntax Quick Example 
defmodule MyApp.Post do
  use Ash.Resource,
    data_layer: AshPostgres.DataLayer,
    extensions: [AshFeistelCipher]

  postgres do
    table "posts"
    repo MyApp.Repo
  end

  attributes do
    integer_sequence :seq
    encrypted_integer_primary_key :id, from: :seq
    
    attribute :title, :string, allow_nil?: false
  end
end
defmodule MyApp.Post do
  use Ash.Resource,
    data_layer: AshPostgres.DataLayer,
    extensions: [AshFeistelCipher]

  postgres do
    table "posts"
    repo MyApp.Repo
  end

  attributes do
    integer_sequence :seq
    encrypted_integer_primary_key :id, from: :seq
    
    attribute :title, :string, allow_nil?: false
  end
end
# Create posts - seq and id are auto-generated
post = MyApp.Post.create!(%{title: "Hello World"})
# => %MyApp.Post{seq: 1, id: 3_141_592_653, title: "Hello World"}

post2 = MyApp.Post.create!(%{title: "Second Post"})
# => %MyApp.Post{seq: 2, id: 2_718_281_828, title: "Second Post"}

# Query by encrypted id
MyApp.Post.get!(3_141_592_653)
# Create posts - seq and id are auto-generated
post = MyApp.Post.create!(%{title: "Hello World"})
# => %MyApp.Post{seq: 1, id: 3_141_592_653, title: "Hello World"}

post2 = MyApp.Post.create!(%{title: "Second Post"})
# => %MyApp.Post{seq: 2, id: 2_718_281_828, title: "Second Post"}

# Query by encrypted id
MyApp.Post.get!(3_141_592_653)
Installation 
mix igniter.install ash_feistel_cipher
mix ash.codegen create_post
mix igniter.install ash_feistel_cipher
mix ash.codegen create_post
📦 Hex: https://hex.pm/packages/ash_feistel_cipher
🐙 GitHub: https://github.com/devall-org/ash_feistel_cipher Built on top of feistel_cipher library.
1 Reply
jart
jart•2mo ago
Okay wow that’s super cool!

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