This library is under development, and, like the secp256k1 C library (through secp256k1-sys Rust crate) it depends on, this is a research effort to determine an optimal API for end-users of the bitcoinjs ecosystem.

npm install tiny-secp256k1

yarn add tiny-secp256k1

Previous version of tiny-secp256k1 implement C++ addon through NAN (Native Abstractions for Node.js) and elliptic as fallback when addon can not be built or in browser-like environement.

Current version use Rust crate (which use C library) compiled to WebAssembly. With Wasm same code executed in any environment. Wasm is faster than elliptic but slower than node bindings (results in PR or you can run own benchmark in benches directory).

For building locally you need C/C++ toolchain, Rust nightly version and wasm-opt from binaryen.

rustup is a recommended way to install Rust. You also will need wasm32-unknown-unknown target.

rustup toolchain install nightly --target wasm32-unknown-unknown --component clippy --component rustfmt

After installing development dependencies with npm you can build Wasm:

make build-wasm

or run tests:

make test

Alternative way is to use Docker:

% docker build -t tiny-secp256k1 .
% docker run -it --rm -v `pwd`:/tiny-secp256k1 -w /tiny-secp256k1 tiny-secp256k1
# npm install --unsafe-perm
# make test
# make clean

tiny-secp256k1 includes two examples. First is simple script for Node.js which generate random data and print arguments and methods results. Second is React app.

React app is builded in GitHub Actions on each commit to master branch and uploaded to gh-pages branch, which is always available online: https://bitcoinjs.github.io/tiny-secp256k1/

isPoint :: Buffer -> Bool

Returns false if

• A is not encoded with a sequence tag of 0x02, 0x03 or 0x04
• A.x is not in [1...p - 1]
• A.y is not in [1...p - 1]

isPointCompressed :: Buffer -> Bool

Returns false if the signature is not compressed.

isPrivate :: Buffer -> Bool

Returns false if

• d is not 256-bit, or
• d is not in [1..order - 1]

pointAdd :: Buffer -> Buffer [-> Bool] -> Maybe Buffer

Returns null if result is at infinity.

• Expected Point if !isPoint(A)
• Expected Point if !isPoint(B)

pointAddScalar :: Buffer -> Buffer [-> Bool] -> Maybe Buffer

Returns null if result is at infinity.

• Expected Point if !isPoint(A)
• Expected Tweak if tweak is not in [0...order - 1]

pointCompress :: Buffer -> Bool -> Buffer

• Expected Point if !isPoint(A)

pointFromScalar :: Buffer [-> Bool] -> Maybe Buffer

Returns null if result is at infinity.

• Expected Private if !isPrivate(d)

pointMultiply :: Buffer -> Buffer [-> Bool] -> Maybe Buffer

Returns null if result is at infinity.

• Expected Point if !isPoint(A)
• Expected Tweak if tweak is not in [0...order - 1]

privateAdd :: Buffer -> Buffer -> Maybe Buffer

Returns null if result is equal to 0.

• Expected Private if !isPrivate(d)
• Expected Tweak if tweak is not in [0...order - 1]

privateSub :: Buffer -> Buffer -> Maybe Buffer

Returns null if result is equal to 0.

• Expected Private if !isPrivate(d)
• Expected Tweak if tweak is not in [0...order - 1]

sign :: Buffer -> Buffer [-> Buffer] -> Buffer

Returns normalized signatures, each of (r, s) values are guaranteed to less than order / 2. Uses RFC6979. Adds e as Added Entropy to the deterministic k generation.

• Expected Private if !isPrivate(d)
• Expected Scalar if h is not 256-bit
• Expected Extra Data (32 bytes) if e is not 256-bit

verify :: Buffer -> Buffer -> Buffer -> Bool

Returns false if any of (r, s) values are equal to 0, or if the signature is rejected.

If strict is true, valid signatures with any of (r, s) values greater than order / 2 are rejected.

• Expected Point if !isPoint(Q)
• Expected Signature if signature has any (r, s) values not in range [0...order - 1]
• Expected Scalar if h is not 256-bit

This library uses the native library secp256k1 by the bitcoin-core developers through Rust crate secp256k1-sys, including derivatives of its tests and test vectors.