Merge pull request #79 from randombit/jack/update-readme-for-bls-short-sigs

Update the README to describe BLS short signature support

README.md

@@ -579,6 +579,14 @@ Main methods and properties are:
 - `Signature` property with `fromHex`, `toHex` methods
 - `fields` containing `Fp`, `Fp2`, `Fp6`, `Fp12`, `Fr`
 
+The default BLS uses short public keys (with public keys in G1 and signatures in G2).
+Short signatures (public keys in G2 and signatures in G1) is also supported, using:
+
+- `getPublicKeyForShortSignatures(privateKey)`
+- `signShortSignature(message, privateKey)`
+- `verifyShortSignature(signature, message, publicKey)`
+- `aggregateShortSignatures(signatures)`
+
 Right now we only implement BLS12-381 (compatible with ETH and others),
 but in theory defining BLS12-377, BLS24 should be straightforward. An example:
 
@@ -627,15 +635,25 @@ Full types:
 
 ```ts
 getPublicKey: (privateKey: PrivKey) => Uint8Array;
+getPublicKeyForShortSignatures: (privateKey: PrivKey) => Uint8Array;
 sign: {
   (message: Hex, privateKey: PrivKey): Uint8Array;
   (message: ProjPointType<Fp2>, privateKey: PrivKey): ProjPointType<Fp2>;
 };
+signShortSignature: {
+  (message: Hex, privateKey: PrivKey): Uint8Array;
+  (message: ProjPointType<Fp>, privateKey: PrivKey): ProjPointType<Fp>;
+};
 verify: (
   signature: Hex | ProjPointType<Fp2>,
   message: Hex | ProjPointType<Fp2>,
   publicKey: Hex | ProjPointType<Fp>
 ) => boolean;
+verifyShortSignature: (
+  signature: Hex | ProjPointType<Fp>,
+  message: Hex | ProjPointType<Fp>,
+  publicKey: Hex | ProjPointType<Fp2>
+) => boolean;
 verifyBatch: (
   signature: Hex | ProjPointType<Fp2>,
   messages: (Hex | ProjPointType<Fp2>)[],
@@ -649,6 +667,10 @@ aggregateSignatures: {
   (signatures: Hex[]): Uint8Array;
   (signatures: ProjPointType<Fp2>[]): ProjPointType<Fp2>;
 };
+aggregateShortSignatures: {
+  (signatures: Hex[]): Uint8Array;
+  (signatures: ProjPointType<Fp>[]): ProjPointType<Fp>;
+};
 millerLoop: (ell: [Fp2, Fp2, Fp2][], g1: [Fp, Fp]) => Fp12;
 pairing: (P: ProjPointType<Fp>, Q: ProjPointType<Fp2>, withFinalExponent?: boolean) => Fp12;
 G1: CurvePointsRes<Fp> & ReturnType<typeof htf.createHasher<Fp>>;