An elixir library for elliptic curve cryptography (MIT License). You can use it to sign messages and to verify signatures with a public key.
Use an existing elliptic curve public key pair or generate one using openssl (adapt the curve name according to your needs):
openssl ecparam -out ec_private_key.pem -name secp521r1 -genkey
openssl ec -in ec_private_key.pem -pubout -out ec_public_key.pem
Simply add {:ecc, "~>0.1.0"} to the dependencies in your projects mix.exs file and run mix deps.get ecc
ECC is a GenServer-Module. You can start a new process passing in both the private and the public key combined in one (still pem-style) string:
pem_public = File.read!("ec_public_key.pem")
pem_private = File.read!("ec_private_key.pem")
pem = Enum.join([pem_public, pem_private])
{:ok, _} = ECC.start_link(pem, :ecc)
{:ok, signature} = GenServer.call(:ecc, {:sign, "Hello", :sha512})
public_key = GenServer.call(:ecc, :get_public_key)
{:ok, result} = GenServer.call(:ecc, {:verify_signature, "Hello", signature, public_key, :sha512})
IO.puts("Hello == Hello? #{result}") # true
{:ok, result} = GenServer.call(:ecc, {:verify_signature, "World", signature, public_key, :sha512})
IO.puts("Hello == World? #{result}") # falseYou can also use ECC.Crypto as a library. The pem-string passed to ECC.Crypto.parse_public_key/1 needs to additionally include an EC PARAMETERS section. In the example, we therefore join both pems to one string:
pem_public = File.read!("ec_public_key.pem")
pem_private = File.read!("ec_private_key.pem")
pem = Enum.join([pem_public, pem_private])
{:ok, public_key} = ECC.Crypto.parse_public_key(pem)
{:ok, private_key} = ECC.Crypto.parse_private_key(pem)
{:ok, signature} = ECC.Crypto.sign("Hello", :sha512, private_key)
{:ok, result} = ECC.Crypto.verify_signature("Hello", signature, :sha512, public_key)
IO.puts("Hello == Hello? #{result}") # true
{:ok, result} = ECC.Crypto.verify_signature("World", signature, :sha512, public_key)
IO.puts("Hello == World? #{result}") # false