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author | Joey Hess <joeyh@joeyh.name> | 2016-08-10 12:16:44 -0400 |
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committer | Joey Hess <joeyh@joeyh.name> | 2016-08-10 12:16:44 -0400 |
commit | 90b7c385f4e2f293502f9aca38aaa041b7b2f486 (patch) | |
tree | 5cc2d68b41406081d9c52271af5852ab148d1ba6 /Types.hs | |
parent | 730c54a40681776aaaab1b727af42559cf1592fe (diff) | |
download | keysafe-90b7c385f4e2f293502f9aca38aaa041b7b2f486.tar.gz |
types for new version storage scheme
Diffstat (limited to 'Types.hs')
-rw-r--r-- | Types.hs | 81 |
1 files changed, 4 insertions, 77 deletions
@@ -6,94 +6,21 @@ import Types.Cost import Entropy import qualified Data.ByteString as B import qualified Data.ByteString.Lazy as BL -import qualified Crypto.Argon2 as Argon2 import Data.String -- | keysafe stores secret keys. newtype SecretKey = SecretKey B.ByteString --- | Objects stored on a keysafe server are (probably) a shard of an --- encrypted secret key. -newtype StorableObject = StorableObject { fromStorableObject :: BL.ByteString } - --- | Parameters for sharding. The secret is split into --- N objects, such that only M are needed to reconstruct it. -data ShardParams = ShardParams - { totalObjects :: Int -- ^ N - , neededObjects :: Int -- ^ M - } - --- | keysafe stores data for a long time, and needs to be able to process --- data from a long time ago when restoring a key. We don't want to be --- locked into old choices of crypto primitives etc forever. --- --- So, every parameter that can be tuned is configured in this data --- structure. Carefully chosen parts of this are exposed at various points --- in the data stored for a key, to allow future versions of keysafe to --- make the right decisions when processing it. -data Tunables = Tunables - { shardParams :: ShardParams - , objectSize :: Int - -- ^ a StorableObject is exactly this many bytes in size - , expensiveHashTunable :: ExpensiveHashTunable - , encryptionTunable :: EncryptionTunable - , decryptionPuzzleTunable :: DecryptionPuzzleTunable - } - --- | An expensive hash, used to make it hard to crack an encrypted secret key. -data ExpensiveHashTunable = UseArgon2 Argon2.HashOptions (Cost CreationOp) - deriving (Show) - --- | What encryption to use. -data EncryptionTunable = UseAES256 - deriving (Show) - --- | An additional puzzle that makes decryption more expensive. -data DecryptionPuzzleTunable = KeyBlindingLeftSide (Cost DecryptionOp) - deriving (Show) - -defaultTunables :: Tunables -defaultTunables = Tunables - { shardParams = ShardParams { totalObjects = 3, neededObjects = 2 } - , objectSize = 1024*64 -- 64 kb - , expensiveHashTunable = UseArgon2 argonoptions argoncost - , encryptionTunable = UseAES256 - -- AES can be calculated more efficiently by a GPU, so the - -- cost is a GPU cost. - -- This is set to only 1 minute because GPUs are quite a lot - -- faster than CPUs at AES, and so setting it higher would make - -- clients too slow at key recovery. - , decryptionPuzzleTunable = KeyBlindingLeftSide (GPUCost (Seconds 60)) - } - where - argonoptions = Argon2.HashOptions - { Argon2.hashIterations = 10000 - , Argon2.hashMemory = 131072 -- 128 mebibtyes per thread - , Argon2.hashParallelism = 4 -- 4 threads - , Argon2.hashVariant = Argon2.Argon2i - } - -- argon2 is GPU and ASIC resistent, so it uses CPU time. - -- The above HashOptions were benchmarked at 661 seconds CPU time - -- on a 2 core Intel(R) Core(TM) i5-4210Y CPU @ 1.50GHz. - -- Since cost is measured per core, we double that. - argoncost = CPUCost (Seconds (2*600)) - --- | Dials back cryptographic difficulty, not for production use. -testModeTunables :: Tunables -testModeTunables = Tunables - { shardParams = ShardParams { totalObjects = 3, neededObjects = 2 } - , objectSize = 1024*64 - , expensiveHashTunable = UseArgon2 Argon2.defaultHashOptions (CPUCost (Seconds (2*600))) - , encryptionTunable = UseAES256 - , decryptionPuzzleTunable = KeyBlindingLeftSide (GPUCost (Seconds 60)) - } - -- | The secret key, encrypted with a password. data EncryptedSecretKey = EncryptedSecretKey B.ByteString (CostCalc BruteForceOp UnknownPassword) instance Bruteforceable EncryptedSecretKey UnknownPassword where getBruteCostCalc (EncryptedSecretKey _ cc) = cc +-- | Objects stored on a keysafe server are (probably) a shard of an +-- encrypted secret key. +newtype StorableObject = StorableObject { fromStorableObject :: BL.ByteString } + -- | A password used to encrypt a key stored in keysafe. newtype Password = Password B.ByteString deriving (IsString) |