f87da3b5ba
...this is the standard way to sign messages in bitcoin-qt. Note that the format of a compressed signature, for messages, is quite distinct from DER format, which is used in transactions. This commit also adds support for recovering the public key from a signature, which is necessary for this. The code for public key recover is taken from bitcoinjs-lib.
62 lines
1.6 KiB
JavaScript
62 lines
1.6 KiB
JavaScript
'use strict';
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var coinUtil = require('../util');
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var Key = require('./Key');
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var bignum = require('bignum');
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var coinUtil = require('../util');
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var Message = function() {};
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//creates DER format signatures.
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//probably not what you want.
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Message.sign = function(str, key) {
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var hash = Message.magicHash(str);
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var sig = key.signSync(hash);
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return sig;
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};
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//verifies compressed signatures
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Message.verifyWithPubKey = function(pubkey, message, sig) {
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var hash = Message.magicHash(message);
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var key = new Key();
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if (pubkey.length == 65)
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key.compressed = false;
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key.public = pubkey;
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return key.verifySignatureSync(hash, sig);
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};
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//creates compressed format signatures.
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//you probably want this, not .sign
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Message.signMessage = function(str, key) {
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var hash = Message.magicHash(str);
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var privnum = bignum.fromBuffer(key.private);
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var sig = Key.signCompressed(hash, privnum);
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return sig;
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};
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//verifies compressed signatures
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Message.verifyMessage = function(pubkeyhash, message, sig) {
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var hash = Message.magicHash(message);
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return Key.verifyCompressed(hash, sig, pubkeyhash);
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};
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//TODO: Message.verify ... with address, not pubkey
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Message.magicBytes = new Buffer('Bitcoin Signed Message:\n');
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Message.magicHash = function(str) {
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var magicBytes = Message.magicBytes;
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var prefix1 = coinUtil.varIntBuf(magicBytes.length);
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var message = new Buffer(str);
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var prefix2 = coinUtil.varIntBuf(message.length);
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var buf = Buffer.concat([prefix1, magicBytes, prefix2, message]);
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var hash = coinUtil.twoSha256(buf);
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return hash;
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};
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module.exports = Message;
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