-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Merkle Hash Tree
--   
--   Purely functional Merkle hash tree which implements appe nd-only logs
--   and provides both inclusion proof and consistency proof.
@package hash-tree
@version 0.0.0


-- | Two-way (binary) Merkle Hash Trees which implements append-only logs
--   and provides both inclusion proof and consistency proof. The API
--   design is inspired by Certificate Transparency defined in RFC 6962.
module Data.HashTree

-- | Settings for Merkle Hash Trees. The first parameter is input data
--   type. The second one is digest data type.
--   
--   To create this, use <a>defaultSettings</a>:
--   
--   <pre>
--   defaultSettings { hash0 = ..., hash1 = ..., hash2 = ... }
--   </pre>
data Settings inp ha

-- | A default Settings with <a>ByteString</a> and <a>SHA256</a>. This can
--   be used for CT(Certificate Transparency) defined in RFC 6962.
defaultSettings :: Settings ByteString SHA256

-- | A hash value for non input element.
hash0 :: Settings inp ha -> Digest ha

-- | A hash function for one input element to calculate the leaf digest.
hash1 :: Settings inp ha -> inp -> Digest ha

-- | A hash function for two input elements to calculate the internal
--   digest.
hash2 :: Settings inp ha -> Digest ha -> Digest ha -> Digest ha

-- | The data type for Merkle Hash Trees. The first parameter is input data
--   type. The second one is digest data type.
data MerkleHashTrees inp ha

-- | Getting the root information of the Merkle Hash Tree. A pair of the
--   current size and the current Merle Tree Hash is returned.
info :: MerkleHashTrees inp ha -> (TreeSize, Digest ha)

-- | Getting the log size
size :: MerkleHashTrees inp ha -> TreeSize

-- | Getting the Merkle Tree Hash.
digest :: TreeSize -> MerkleHashTrees inp ha -> Maybe (Digest ha)

-- | The size of hash tree.
type TreeSize = Int

-- | The position of the target element from 0.
type Index = Int

-- | Creating an empty <a>MerkleHashTrees</a>.
--   
--   <pre>
--   &gt;&gt;&gt; info $ empty defaultSettings
--   (0,e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855)
--   </pre>
empty :: Settings inp ha -> MerkleHashTrees inp ha

-- | Creating a Merkle Hash Tree from a list of elements. O(n log n)
--   
--   <pre>
--   &gt;&gt;&gt; info $ fromList defaultSettings ["0","1","2"]
--   (3,725d5230db68f557470dc35f1d8865813acd7ebb07ad152774141decbae71327)
--   </pre>
fromList :: (ByteArrayAccess inp, HashAlgorithm ha) => Settings inp ha -> [inp] -> MerkleHashTrees inp ha

-- | Adding (appending) an element. O(log n)
--   
--   <pre>
--   &gt;&gt;&gt; info $ add "1" $ empty defaultSettings
--   (1,2215e8ac4e2b871c2a48189e79738c956c081e23ac2f2415bf77da199dfd920c)
--   </pre>
add :: (ByteArrayAccess inp, HashAlgorithm ha) => inp -> MerkleHashTrees inp ha -> MerkleHashTrees inp ha

-- | The type for inclusion proof (aka audit proof).
data InclusionProof ha

-- | The default value for <a>InclusionProof</a> just to create a new
--   value.
defaultInclusionProof :: InclusionProof ha

-- | The index for the target.
leafIndex :: InclusionProof ha -> Index

-- | The hash tree size.
treeSize :: InclusionProof ha -> TreeSize

-- | A list of digest for inclusion.
inclusion :: InclusionProof ha -> [Digest ha]

-- | Generating <a>InclusionProof</a> for the target at the server side.
generateInclusionProof :: Digest ha -> TreeSize -> MerkleHashTrees inp ha -> Maybe (InclusionProof ha)

-- | Verifying <a>InclusionProof</a> at the client side.
--   
--   <pre>
--   &gt;&gt;&gt; let target = "3"
--   
--   &gt;&gt;&gt; let mht = fromList defaultSettings ["0","1","2",target,"4","5","6"]
--   
--   &gt;&gt;&gt; let treeSize = 5
--   
--   &gt;&gt;&gt; let leafDigest = hash1 defaultSettings target
--   
--   &gt;&gt;&gt; let Just proof = generateInclusionProof leafDigest treeSize mht
--   
--   &gt;&gt;&gt; let Just rootDigest = digest treeSize mht
--   
--   &gt;&gt;&gt; verifyInclusionProof defaultSettings leafDigest rootDigest proof
--   True
--   </pre>
verifyInclusionProof :: (ByteArrayAccess inp, HashAlgorithm ha) => Settings inp ha -> Digest ha -> Digest ha -> InclusionProof ha -> Bool

-- | The type for consistency proof.
data ConsistencyProof ha

-- | The default value for <a>ConsistencyProof</a> just to create a new
--   value.
defaultConsistencyProof :: ConsistencyProof ha

-- | The first hash tree size.
firstTreeSize :: ConsistencyProof ha -> TreeSize

-- | The second hash tree size.
secondTreeSize :: ConsistencyProof ha -> TreeSize

-- | A list of digest for consistency.
consistency :: ConsistencyProof ha -> [Digest ha]

-- | Generating <a>ConsistencyProof</a> for the target at the server side.
generateConsistencyProof :: TreeSize -> TreeSize -> MerkleHashTrees inp ha -> Maybe (ConsistencyProof ha)

-- | Verifying <a>ConsistencyProof</a> at the client side.
--   
--   <pre>
--   &gt;&gt;&gt; let mht0 = fromList defaultSettings ["0","1","2","3"]
--   
--   &gt;&gt;&gt; let (m, digestM) = info mht0
--   
--   &gt;&gt;&gt; let mht1 = add "6" $ add "5" $ add "4" mht0
--   
--   &gt;&gt;&gt; let (n, digestN) = info mht1
--   
--   &gt;&gt;&gt; let Just proof = generateConsistencyProof m n mht1
--   
--   &gt;&gt;&gt; verifyConsistencyProof defaultSettings digestM digestN proof
--   True
--   </pre>
verifyConsistencyProof :: (ByteArrayAccess inp, HashAlgorithm ha) => Settings inp ha -> Digest ha -> Digest ha -> ConsistencyProof ha -> Bool