BLS Signatures

A browser friendly implementation of bls-signatures in TypeScript, based off of the Python implementation.

Introduction

BLS Signatures is a cryptographic library used by projects and blockchains such as the Chia blockchain. It is a type of elliptic curve cryptography.

This particular implementation is written with TypeScript, and is not bindings to native code. This allows it to be used in the browser as well. However, if you prefer native bindings, you should check out this library instead.

Usage

In this library, bytes are stored using the Uint8Array typed array class from the ECMAScript specification for multiplatform support.

By design, the functions and methods exposed by this library are synchronous and everything is exported for ease of use.

Since it is written in TypeScript, there are built-in typings for IntelliSense. The following documentation is non-exhaustive, but should be enough for most uses.

Documentation

• AugSchemeMPL
• BasicSchemeMPL
• PopSchemeMPL
• PrivateKey
• JacobianPoint
• Byte Utils

AugSchemeMPL

This scheme is from the BLS spec in the IETF. AugSchemeMPL is used by the Chia Network and is more secure but less efficient.

static keygen(seed)

• seed is a Uint8Array.
• Returns a PrivateKey.

static sign(privateKey, message)

• privateKey is a PrivateKey.
• message is a Uint8Array.
• Returns a JacobianPoint signature.

static sign_prepend(privateKey, message, prependPublicKey)

• privateKey is a PrivateKey.
• message is a Uint8Array.
• prependPublicKey is a JacobianPoint public key.
• Returns a JacobianPoint signature.

static verify(publicKey, message, signature)

• publicKey is a JacobianPoint public key.
• message is a Uint8Array.
• signature is a JacobianPoint signature.
• Returns a boolean for if the signature is valid.

static aggregate(signatures)

• signatures is an Array<JacobianPoint> of signatures.
• Returns an aggregated JacobianPoint.

static aggregateVerify(publicKeys, messages, signature)

• publicKeys is an Array<JacobianPoint> of public keys.
• messages is an Array<Uint8Array>.
• signature is a JacobianPoint signature.
• Returns a boolean for if the signatures are valid.

deriveChildSk(privateKey, index)

• privateKey is a PrivateKey.
• index is a number.
• Returns the hardened child PrivateKey at the index.

deriveChildSkUnhardened(privateKey, index)

• privateKey is a PrivateKey.
• index is a number.
• Returns the unhardened child PrivateKey at the index.

deriveChildPkUnhardened(publicKey, index)

• publicKey is a JacobianPoint public key.
• index is a number.
• Returns the unhardened child JacobianPoint public key at the index.

BasicSchemeMPL

This scheme is from the BLS spec in the IETF. BasicSchemeMPL is very fast, but not as secure as the other schemes.

static keygen(seed)

• seed is a Uint8Array.
• Returns a PrivateKey.

static sign(privateKey, message)

• privateKey is a PrivateKey.
• message is a Uint8Array.
• Returns a JacobianPoint signature.

static verify(publicKey, message, signature)

• publicKey is a JacobianPoint public key.
• message is a Uint8Array.
• signature is a JacobianPoint signature.
• Returns a boolean for if the signature is valid.

static aggregate(signatures)

• signatures is an Array<JacobianPoint> of signatures.
• Returns an aggregated JacobianPoint.

static aggregateVerify(publicKeys, messages, signature)

• publicKeys is an Array<JacobianPoint> of public keys.
• messages is an Array<Uint8Array>.
• signature is a JacobianPoint signature.
• Returns a boolean for if the signatures are valid.

deriveChildSk(privateKey, index)

• privateKey is a PrivateKey.
• index is a number.
• Returns the hardened child PrivateKey at the index.

deriveChildSkUnhardened(privateKey, index)

• privateKey is a PrivateKey.
• index is a number.
• Returns the unhardened child PrivateKey at the index.

deriveChildPkUnhardened(publicKey, index)

• publicKey is a JacobianPoint public key.
• index is a number.
• Returns the unhardened child JacobianPoint public key at the index.

PopSchemeMPL

This scheme is from the BLS spec in the IETF. PopSchemeMPL is secure, but it requires registration, for example with Ethereum 2.0 Proof of Stake.

static keygen(seed)

• seed is a Uint8Array.
• Returns a PrivateKey.

static sign(privateKey, message)

• privateKey is a PrivateKey.
• message is a Uint8Array.
• Returns a JacobianPoint signature.

static verify(publicKey, message, signature)

• publicKey is a JacobianPoint public key.
• message is a Uint8Array.
• signature is a JacobianPoint signature.
• Returns a boolean for if the signature is valid.

static aggregate(signatures)

• signatures is an Array<JacobianPoint> of signatures.
• Returns an aggregated JacobianPoint.

static aggregateVerify(publicKeys, messages, signature)

• publicKeys is an Array<JacobianPoint> of public keys.
• messages is an Array<Uint8Array>.
• signature is a JacobianPoint signature.
• Returns a boolean for if the signatures are valid.

static popProve(privateKey)

• privateKey is a PrivateKey.
• Returns a JacobianPoint proof of possession.

static popVerify(publicKey, proof)

• publicKey is a JacobianPoint public key.
• proof is a JacobianPoint proof of possession.
• Returns a boolean for if the proof of possession is valid.

static fastAggregateVerify(publicKeys, message, signature)

• publicKeys is an Array<JacobianPoint> of public keys.
• message is a Uint8Array.
• signature is a JacobianPoint.
• Returns a boolean for if the signature is valid.

deriveChildSk(privateKey, index)

• privateKey is a PrivateKey.
• index is a number.
• Returns the hardened child PrivateKey at the index.

deriveChildSkUnhardened(privateKey, index)

• privateKey is a PrivateKey.
• index is a number.
• Returns the unhardened child PrivateKey at the index.

deriveChildPkUnhardened(publicKey, index)

• publicKey is a JacobianPoint public key.
• index is a number.
• Returns the unhardened child JacobianPoint public key at the index.

PrivateKey

static fromBytes(bytes)

• bytes is a Uint8Array.
• Returns a PrivateKey.

static fromHex(hex)

• hex is a hex string.
• Returns a PrivateKey.

static fromSeed(seed)

• seed is a Uint8Array.
• Returns a PrivateKey derived from the seed.

static fromBigInt(value)

• value is a bigint.
• Returns a PrivateKey.

static aggregate(privateKeys)

• privateKeys is an Array<PrivateKey>.
• Returns an aggregated PrivateKey.

constructor(value)

• value is a bigint.

getG1()

• Returns a derived JacobianPoint public key.

toBytes()

• Returns a Uint8Array representation.

toHex()

• Returns a hex string representation.

toString()

• Returns a string representation.

equals(value)

• value is a PrivateKey.
• Returns a boolean for if the values are equal.

JacobianPoint

This represents both G1Element and G2Element values, which are used for public keys and signatures, respectively.

static fromBytes(bytes, isExtension)

• bytes is a Uint8Array.
• isExtension is a boolean.
• Returns a JacobianPoint.

static fromHex(hex, isExtension)

• hex is a hex string.
• isExtension is a boolean.
• Returns a JacobianPoint.

static generateG1()

• Returns a JacobianPoint G1Element.

static generateG2()

• Returns a JacobianPoint G2Element.

static infinityG1()

• Returns a JacobianPoint G1Element at infinity.

static infinityG2()

• Returns a JacobianPoint G2Element at infinity.

static fromBytesG1(bytes)

• bytes is a Uint8Array.
• Returns a JacobianPoint G1Element.

static fromBytesG2(bytes)

• bytes is a Uint8Array.
• Returns a JacobianPoint G2Element.

static fromHexG1(hex)

• hex is a hex string.
• Returns a JacobianPoint G1Element.

static fromHexG2(hex)

• hex is a hex string.
• Returns a JacobianPoint G2Element.

constructor(x, y, z, isInfinity)

• x, y, and z are Fq or Fq2.
• isInfinity is a boolean.

isOnCurve()

• Returns a boolean for if the point is on curve.

isValid()

• Returns a boolean for if the point is valid.

getFingerprint()

• Returns a small number fingerprint that identifies the point.

toAffine()

• Returns an AffinePoint representation.

toBytes()

• Returns a Uint8Array representation.

toHex()

• Returns a hex string representation.

toString()

• Returns a string representation.

double()

• Returns a JacobianPoint that is double the value.

negate()

• Returns a JacobianPoint that is the opposite value.

add(value)

• value is a JacobianPoint.
• Returns a JacobianPoint that is the sum of the points.

multiply(value)

• value is an Fq or bigint.
• Returns a JacobianPoint that is scalar multiplied.

equals(value)

• value is a JacobianPoint.
• Returns a boolean for if the values are equal.

clone()

• Returns an exact JacobianPoint clone.

Byte Utils

This is a collection of byte utils that can be directly imported and called, and are not part of a class.

intToBytes(value, size, endian, signed?)

• value is a number.
• size is a number of bytes.
• endian is either "big" or "little".
• signed is a boolean, by default false.
• Returns a Uint8Array.

bytesToInt(bytes, endian, signed?)

• bytes is a Uint8Array.
• endian is either "big" or "little".
• signed is a boolean, by default false.
• Returns a number.

encodeInt(value)

• value is a number.
• Returns a Uint8Array encoded the way that Chia Network's CLVM does.

decodeInt(bytes)

• bytes is a Uint8Array.
• Returns a number decoded the way that Chia Network's CLVM does.

bigIntToBytes(value, size, endian, signed?)

• value is a bigint.
• size is a number of bytes.
• endian is either "big" or "little".
• signed is a boolean, by default false.
• Returns a Uint8Array.

bytesToBigInt(bytes, endian, signed?)

• bytes is a Uint8Array.
• endian is either "big" or "little".
• signed is a boolean, by default false.
• Returns a bigint.

encodeBigInt(value)

• value is a bigint.
• Returns a Uint8Array encoded the way that Chia Network's CLVM does.

decodeBigInt(bytes)

• bytes is a Uint8Array.
• Returns a bigint decoded the way that Chia Network's CLVM does.

concatBytes(...lists)

• lists is an Array<Uint8Array>.
• Returns a concatenated Uint8Array.

bytesEqual(a, b)

• a is a Uint8Array.
• b is a Uint8Array.
• Returns a boolean for if the bytes are exactly equal.

toHex(bytes)

• bytes is a Uint8Array.
• Returns a hex string.

fromHex(hex)

• hex is a hex string.
• Returns a Uint8Array.