ECSSA/secp256k1 + SHA-256

Abstract

This is a wasm version of mcl/ecdsa.h

News

serialize() supports the format defined at BitCoin

for Node.js

npm test

how to use

const ecdsa = require('ecdsa-wasm')

// create secret key
const sec = new ecdsa.SecretKey()

// initialize sec
sec.setByCSPRNG()

// get public key
const pub = sec.getPublicKey()

// make signature
const sig = sec.sign("abc")

// verify signatpure by pub
> pub.verify(sig, "abc")
true
> pub.verify(sig, "abcd")
false

// create precomputed public key(faster than pub)
const ppub = new ecdsa.PrecomputedPublicKey()
// initialize ppub
ppub.init(pub)

// verify signature by ppub
> ppub.verify(sig, "abc")
true
> ppub.verify(sig, "abcd")
false

// destroy ppub if unnecessary
ppub.destroy()

serialization

• SecretKey.serialize() return 32-bytes Uint8Array as big-endian
• PublicKey.serialize() return 65-bytes Uint8Array as 0x04 + x + y
• PublicKey.serializeCompressed() return 33-bytes Uint8Array as 0x02 (y is even) or 0x03 (y is odd) + x
• Signature.serialize() return DER-format
• SecretKey.deserialize(a)
• PublicKey.deserialize(a)
• Signature.deserialize(a)
  • take Uint8Array of a and constract the object

how to build ecdsa_c.js

Install emscripten.

git clone --recurse-submodules [email protected]:herumi/ecdsa-wasm
cd ecdsa-wasm
make -C src wasm

License

modified new BSD License http://opensource.org/licenses/BSD-3-Clause

Author

光成滋生 MITSUNARI Shigeo([email protected])