elixir 的加解密demo
在libcluster项目里，有关于crypto的加解密的东西，包括
encrypt和decrypt， 向量IV,key，和填充等基础概念，和erlang的调用差无二意
直接上代码：
1 defp encrypt(_state, plaintext, password) do 2 iv = :crypto.strong_rand_bytes(16) 3 key = :crypto.hash(:sha256, password) 4 ciphertext = :crypto.crypto_one_time(:aes_256_cbc, key, iv, pkcs7_pad(plaintext), true) 5 6 {:ok, iv, ciphertext} 7 end 8 9 defp decrypt(state, ciphertext, password, iv) do 10 key = :crypto.hash(:sha256, password) 11 12 with {:unpadding, {:ok, padded}} <- {:unpadding, safe_decrypt(state, key, iv, ciphertext)}, 13 {:decrypt, {:ok, _plaintext} = res} <- {:decrypt, pkcs7_unpad(padded)} do 14 res 15 else 16 {:unpadding, :error} -> {:error, :decrypt} 17 {:decrypt, :error} -> {:error, :unpadding} 18 end 19 end 20 21 defp safe_decrypt(state, key, iv, ciphertext) do 22 try do 23 {:ok, :crypto.crypto_one_time(:aes_256_cbc, key, iv, ciphertext, false)} 24 catch 25 :error, {tag, {file, line}, desc} -> 26 warn(state.topology, "decryption failed: #{inspect(tag)} (#{file}:#{line}): #{desc}") 27 :error 28 end 29 end 30 31 # 32 # Pads a message using the PKCS #7 cryptographic message syntax. 33 # 34 # from: https://github.com/izelnakri/aes256/blob/master/lib/aes256.ex 35 # 36 # See: https://tools.ietf.org/html/rfc2315 37 # See: `pkcs7_unpad/1` 38 defp pkcs7_pad(message) do 39 bytes_remaining = rem(byte_size(message), 16) 40 padding_size = 16 - bytes_remaining 41 message <> :binary.copy(<<padding_size>>, padding_size) 42 end 43 44 # 45 # Unpads a message using the PKCS #7 cryptographic message syntax. 46 # 47 # from: https://github.com/izelnakri/aes256/blob/master/lib/aes256.ex 48 # 49 # See: https://tools.ietf.org/html/rfc2315 50 # See: `pkcs7_pad/1` 51 defp pkcs7_unpad(<<>>), do: :error 52 53 defp pkcs7_unpad(message) do 54 padding_size = :binary.last(message) 55 56 if padding_size <= 16 do 57 message_size = byte_size(message) 58 59 if binary_part(message, message_size, -padding_size) === 60 :binary.copy(<<padding_size>>, padding_size) do 61 {:ok, binary_part(message, 0, message_size - padding_size)} 62 else 63 :error 64 end 65 else 66 :error 67 end 68 end
