Crypto.Secp256k1

Crytpographic functions from Bitcoin’s secp256k1 library.

Core Types

data SecKey

data PubKeyXY

data PubKeyXO

data KeyPair

data Signature

data RecoverableSignature

data Tweak

Parsing and Serialization

importSecKey :: ByteString -> Maybe SecKey

Parses SecKey, will be Nothing if the ByteString corresponds to 0{32} or is not 32 bytes in length

importPubKeyXY :: ByteString -> Maybe PubKeyXY

Parses a 33 or 65 byte PubKeyXY, all other lengths will result in Nothing

exportPubKeyXY :: Bool -> PubKeyXY -> ByteString

Serialize PubKeyXY. First argument True for compressed output (33 bytes), False for uncompressed (65 bytes).

importPubKeyXO :: ByteString -> Maybe PubKeyXO

Parses PubKeyXO from ByteString, will be Nothing if the pubkey corresponds to the Point at Infinity or the the ByteString is not 32 bytes long

exportPubKeyXO :: PubKeyXO -> ByteString

Serializes PubKeyXO to 32 byte ByteString

importSignature :: ByteString -> Maybe Signature

Parses Signature from DER (71 | 72 | 73 bytes) or Compact (64 bytes) representations.

exportSignatureCompact :: Signature -> ByteString

Serializes Signature to Compact (64 byte) representation

exportSignatureDer :: Signature -> ByteString

Serializes Signature to DER (71 | 72 bytes) representation

importRecoverableSignature :: ByteString -> Maybe RecoverableSignature

Parses RecoverableSignature from Compact (65 byte) representation

exportRecoverableSignature :: RecoverableSignature -> ByteString

Serializes RecoverableSignature to Compact (65 byte) representation

importTweak :: ByteString -> Maybe Tweak

Parses Tweak from 32 byte ByteString. If the ByteString is an invalid SecKey then this will yield Nothing

ECDSA Operations

ecdsaVerify :: ByteString -> PubKeyXY -> Signature -> Bool

Verify message signature. True means that the signature is correct.

ecdsaSign :: SecKey -> ByteString -> Maybe Signature

Signs ByteString with SecKey only if ByteString is 32 bytes.

ecdsaSignRecoverable :: SecKey -> ByteString -> Maybe RecoverableSignature

Signs ByteString with SecKey only if ByteString is 32 bytes. Retains ability to compute PubKeyXY from the RecoverableSignature and the original message (ByteString)

ecdsaRecover :: RecoverableSignature -> ByteString -> Maybe PubKeyXY

Computes PubKeyXY from RecoverableSignature and the original message that was signed (must be 32 bytes).

Conversions

recSigToSig :: RecoverableSignature -> Signature

Forgets the recovery id of a signature

derivePubKey :: SecKey -> PubKeyXY

Use SecKey to compute the corresponding PubKeyXY

keyPairCreate :: SecKey -> KeyPair

Compute KeyPair structure from SecKey

keyPairPubKeyXY :: KeyPair -> PubKeyXY

Project PubKeyXY from KeyPair

keyPairPubKeyXO :: KeyPair -> (PubKeyXO, Bool)

Project PubKeyXO from KeyPair as well as parity bit. True indicates that the public key is the same as it would be if you had serialized the PubKeyXO and it was prefixed with flagsTagPubkeyOdd. False indicates it would be prefixed by flagsTagPubkeyEven

xyToXO :: PubKeyXY -> (PubKeyXO, Bool)

Convert PubKeyXY to PubKeyXO. See keyPairPubKeyXO for more information on how to interpret the parity bit.

Tweaks

ecSecKeyTweakAdd :: SecKey -> Tweak -> Maybe SecKey

ecSecKeyTweakMul :: SecKey -> Tweak -> Maybe SecKey

Multiply SecKey by Tweak.

keyPairPubKeyXOTweakAdd :: KeyPair -> Tweak -> Maybe KeyPair

Tweak a KeyPair with a Tweak. If the resulting KeyPair is invalid (0, Infinity), then the result is Nothing

pubKeyCombine :: [PubKeyXY] -> Maybe PubKeyXY

Combine a list of PubKeyXYs into a single PubKeyXY. This will result in Nothing if the group operation results in the Point at Infinity

pubKeyNegate :: PubKeyXY -> PubKeyXY

Negate a PubKeyXY

secKeyNegate :: SecKey -> SecKey

Negate a SecKey

pubKeyTweakAdd :: PubKeyXY -> Tweak -> Maybe PubKeyXY

Add Tweak to PubKeyXY. This will result in Nothing if the group operation results in the Point at Infinity

pubKeyTweakMul :: PubKeyXY -> Tweak -> Maybe PubKeyXY

Multiply PubKeyXY by Tweak. This will result in Nothing if the group operation results in the Point at Infinity

pubKeyXOTweakAdd :: PubKeyXO -> Tweak -> Maybe PubKeyXY

Add Tweak to PubKeyXO. This will result in Nothing if the group operation results in the Point at Infinity

pubKeyXOTweakAddCheck :: PubKeyXO -> Bool -> PubKeyXO -> Tweak -> Bool

Check that a PubKeyXO is the result of the specified tweak operation. True means it was.

Schnorr Operations

schnorrSign :: KeyPair -> ByteString -> Maybe Signature

Compute a schnorr signature using a KeyPair. The ByteString must be 32 bytes long to get a Just out of this function

data SchnorrExtra a

Extra parameters object for alternative nonce generation

Constructors

Storable a => SchnorrExtra

Fields

• schnorrExtraNonceFunHardened :: ByteString -> SecKey -> PubKeyXO -> ByteString -> a -> Maybe (SizedByteArray 32 ByteString)
• schnorrExtraData :: a

schnorrSignCustom :: forall a. KeyPair -> ByteString -> SchnorrExtra a -> Maybe Signature

Compute a schnorr signature with an alternative scheme for generating nonces, it is not recommended you use this unless you know what you are doing. Instead, favor the usage of schnorrSign

schnorrVerify :: PubKeyXO -> ByteString -> Signature -> Bool

Verify the authenticity of a schnorr signature. True means the Signature is correct.

Other

taggedSha256 :: ByteString -> ByteString -> Digest SHA256

Generate a tagged sha256 digest as specified in BIP340

ecdh :: SecKey -> PubKeyXY -> Digest SHA256

Compute a shared secret using ECDH and SHA256. This algorithm uses your own SecKey, your counterparty's PubKeyXY and results in a 32 byte SHA256 Digest.