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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 | 1x 16x 16x 13x 13x 31x 15x 15x 15x 480x 15x 31x 31x 33x 33x 31x 2x 2x 2x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 16x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 15x 2x 13x 13x 12x 1x 7x 7x 7x 7x 7x 7x 7x 12x 12x 12x 12x | /* @flow */ import { ec as EllipticCurve } from 'elliptic' import crypto from 'crypto' import { getPublicKeyFromPrivate } from '../keys' const ecurve = new EllipticCurve('secp256k1') export type CipherObject = { iv: string, ephemeralPK: string, cipherText: string, mac: string, wasString: boolean } function aes256CbcEncrypt(iv: Buffer, key: Buffer, plaintext: Buffer) { const cipher = crypto.createCipheriv('aes-256-cbc', key, iv) return Buffer.concat([cipher.update(plaintext), cipher.final()]) } function aes256CbcDecrypt(iv: Buffer, key: Buffer, ciphertext: Buffer) { const cipher = crypto.createDecipheriv('aes-256-cbc', key, iv) return Buffer.concat([cipher.update(ciphertext), cipher.final()]) } function hmacSha256(key: Buffer, content: Buffer) { return crypto.createHmac('sha256', key).update(content).digest() } function equalConstTime(b1: Buffer, b2: Buffer) { Iif (b1.length !== b2.length) { return false } let res = 0 for (let i = 0; i < b1.length; i++) { res |= b1[i] ^ b2[i] // jshint ignore:line } return res === 0 } function sharedSecretToKeys(sharedSecret: Buffer) { // generate mac and encryption key from shared secret const hashedSecret = crypto.createHash('sha512').update(sharedSecret).digest() return { encryptionKey: hashedSecret.slice(0, 32), hmacKey: hashedSecret.slice(32) } } export function getHexFromBN(bnInput: Object) { const hexOut = bnInput.toString('hex') if (hexOut.length === 64) { return hexOut } else Eif (hexOut.length < 64) { // pad with leading zeros // the padStart function would require node 9 const padding = '0'.repeat(64 - hexOut.length) return `${padding}${hexOut}` } else { throw new Error('Generated a > 32-byte BN for encryption. Failing.') } } /** * Encrypt content to elliptic curve publicKey using ECIES * @param {String} publicKey - secp256k1 public key hex string * @param {String | Buffer} content - content to encrypt * @return {Object} Object containing (hex encoded): * iv (initialization vector), cipherText (cipher text), * mac (message authentication code), ephemeral public key * wasString (boolean indicating with or not to return a buffer or string on decrypt) * @private */ export function encryptECIES(publicKey: string, content: string | Buffer): CipherObject { const isString = (typeof (content) === 'string') const plainText = Buffer.from(content) // always copy to buffer const ecPK = ecurve.keyFromPublic(publicKey, 'hex').getPublic() const ephemeralSK = ecurve.genKeyPair() const ephemeralPK = ephemeralSK.getPublic() const sharedSecret = ephemeralSK.derive(ecPK) const sharedSecretHex = getHexFromBN(sharedSecret) const sharedKeys = sharedSecretToKeys( new Buffer(sharedSecretHex, 'hex') ) const initializationVector = crypto.randomBytes(16) const cipherText = aes256CbcEncrypt( initializationVector, sharedKeys.encryptionKey, plainText ) const macData = Buffer.concat([initializationVector, new Buffer(ephemeralPK.encodeCompressed()), cipherText]) const mac = hmacSha256(sharedKeys.hmacKey, macData) return { iv: initializationVector.toString('hex'), ephemeralPK: ephemeralPK.encodeCompressed('hex'), cipherText: cipherText.toString('hex'), mac: mac.toString('hex'), wasString: isString } } /** * Decrypt content encrypted using ECIES * @param {String} privateKey - secp256k1 private key hex string * @param {Object} cipherObject - object to decrypt, should contain: * iv (initialization vector), cipherText (cipher text), * mac (message authentication code), ephemeralPublicKey * wasString (boolean indicating with or not to return a buffer or string on decrypt) * @return {Buffer} plaintext * @throws {Error} if unable to decrypt * @private */ export function decryptECIES(privateKey: string, cipherObject: CipherObject): Buffer | string { const ecSK = ecurve.keyFromPrivate(privateKey, 'hex') const ephemeralPK = ecurve.keyFromPublic(cipherObject.ephemeralPK, 'hex').getPublic() const sharedSecret = ecSK.derive(ephemeralPK) const sharedSecretBuffer = new Buffer(getHexFromBN(sharedSecret), 'hex') const sharedKeys = sharedSecretToKeys(sharedSecretBuffer) const ivBuffer = new Buffer(cipherObject.iv, 'hex') const cipherTextBuffer = new Buffer(cipherObject.cipherText, 'hex') const macData = Buffer.concat([ivBuffer, new Buffer(ephemeralPK.encodeCompressed()), cipherTextBuffer]) const actualMac = hmacSha256(sharedKeys.hmacKey, macData) const expectedMac = new Buffer(cipherObject.mac, 'hex') if (!equalConstTime(expectedMac, actualMac)) { throw new Error('Decryption failed: failure in MAC check') } const plainText = aes256CbcDecrypt( ivBuffer, sharedKeys.encryptionKey, cipherTextBuffer ) if (cipherObject.wasString) { return plainText.toString() } else { return plainText } } /** * Sign content using ECDSA * @private * @param {String} privateKey - secp256k1 private key hex string * @param {Object} content - content to sign * @return {Object} contains: * signature - Hex encoded DER signature * public key - Hex encoded private string taken from privateKey * @private */ export function signECDSA(privateKey: string, content: string | Buffer) : { publicKey: string, signature: string } { const contentBuffer = Buffer.from(content) const ecPrivate = ecurve.keyFromPrivate(privateKey, 'hex') const publicKey = getPublicKeyFromPrivate(privateKey) const contentHash = crypto.createHash('sha256').update(contentBuffer).digest() const signature = ecPrivate.sign(contentHash) const signatureString = signature.toDER('hex') return { signature: signatureString, publicKey } } /** * Verify content using ECDSA * @param {String | Buffer} content - Content to verify was signed * @param {String} publicKey - secp256k1 private key hex string * @param {String} signature - Hex encoded DER signature * @return {Boolean} returns true when signature matches publickey + content, false if not * @private */ export function verifyECDSA(content: string | Buffer, publicKey: string, signature: string) { const contentBuffer = Buffer.from(content) const ecPublic = ecurve.keyFromPublic(publicKey, 'hex') const contentHash = crypto.createHash('sha256').update(contentBuffer).digest() return ecPublic.verify(contentHash, signature) } |