From 1f8290ca44df31cc4c4b68b30eef412476ed24e0 Mon Sep 17 00:00:00 2001 From: Gustav Simonsson Date: Tue, 20 Jan 2015 23:55:13 +0100 Subject: [PATCH] Add ImportPreSaleKey * ImportPreSaleKey takes a KeyStore, a presale key JSON (e.g. file content) and a password string. It stores the key in the given key store. * Refactored common AES decryption and moved some functions to crypto.go --- crypto/crypto.go | 104 +++++++++++++++++++++++++++++++++ crypto/key.go | 9 +-- crypto/key_store_passphrase.go | 46 +-------------- crypto/key_store_test.go | 13 +++++ 4 files changed, 123 insertions(+), 49 deletions(-) diff --git a/crypto/crypto.go b/crypto/crypto.go index ac84c6204..066d23dcb 100644 --- a/crypto/crypto.go +++ b/crypto/crypto.go @@ -1,12 +1,19 @@ package crypto import ( + "crypto/aes" + "crypto/cipher" "crypto/ecdsa" "crypto/elliptic" "crypto/rand" "crypto/sha256" + "errors" + "code.google.com/p/go-uuid/uuid" + "code.google.com/p/go.crypto/pbkdf2" "code.google.com/p/go.crypto/ripemd160" + "encoding/hex" + "encoding/json" "github.com/ethereum/go-ethereum/crypto/secp256k1" "github.com/ethereum/go-ethereum/crypto/sha3" "github.com/ethereum/go-ethereum/ethutil" @@ -113,3 +120,100 @@ func Decrypt(prv *ecdsa.PrivateKey, ct []byte) ([]byte, error) { key := ecies.ImportECDSA(prv) return key.Decrypt(rand.Reader, ct, nil, nil) } + +// creates a Key and stores that in the given KeyStore by decrypting a presale key JSON +func ImportPreSaleKey(keyStore KeyStore2, keyJSON []byte, password string) (*Key, error) { + key, err := decryptPreSaleKey(keyJSON, password) + if err != nil { + return nil, err + } + id := uuid.NewRandom() + key.Id = &id + err = keyStore.StoreKey(key, password) + return key, err +} + +func decryptPreSaleKey(fileContent []byte, password string) (key *Key, err error) { + preSaleKeyStruct := struct { + EncSeed string + EthAddr string + Email string + BtcAddr string + }{} + err = json.Unmarshal(fileContent, &preSaleKeyStruct) + if err != nil { + return nil, err + } + encSeedBytes, err := hex.DecodeString(preSaleKeyStruct.EncSeed) + iv := encSeedBytes[:16] + cipherText := encSeedBytes[16:] + /* + See https://github.com/ethereum/pyethsaletool + + pyethsaletool generates the encryption key from password by + 2000 rounds of PBKDF2 with HMAC-SHA-256 using password as salt (:(). + 16 byte key length within PBKDF2 and resulting key is used as AES key + */ + passBytes := []byte(password) + derivedKey := pbkdf2.Key(passBytes, passBytes, 2000, 16, sha256.New) + plainText, err := aes_cbc_decrypt(derivedKey, cipherText, iv) + ethPriv := Sha3(plainText) + ecKey := ToECDSA(ethPriv) + key = &Key{ + Id: nil, + PrivateKey: ecKey, + } + derivedAddr := ethutil.Bytes2Hex(key.Address()) + expectedAddr := preSaleKeyStruct.EthAddr + if derivedAddr != expectedAddr { + err = errors.New("decrypted addr not equal to expected addr") + } + return key, err +} + +func aes_cbc_decrypt(key []byte, cipherText []byte, iv []byte) (plainText []byte, err error) { + aesBlock, err := aes.NewCipher(key) + if err != nil { + return plainText, err + } + decrypter := cipher.NewCBCDecrypter(aesBlock, iv) + paddedPlainText := make([]byte, len(cipherText)) + decrypter.CryptBlocks(paddedPlainText, cipherText) + plainText = PKCS7Unpad(paddedPlainText) + if plainText == nil { + err = errors.New("Decryption failed: PKCS7Unpad failed after decryption") + } + return plainText, err +} + +// From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes +func PKCS7Pad(in []byte) []byte { + padding := 16 - (len(in) % 16) + if padding == 0 { + padding = 16 + } + for i := 0; i < padding; i++ { + in = append(in, byte(padding)) + } + return in +} + +func PKCS7Unpad(in []byte) []byte { + if len(in) == 0 { + return nil + } + + padding := in[len(in)-1] + if int(padding) > len(in) || padding > aes.BlockSize { + return nil + } else if padding == 0 { + return nil + } + + for i := len(in) - 1; i > len(in)-int(padding)-1; i-- { + if in[i] != padding { + return nil + } + } + return in[:len(in)-int(padding)] +} diff --git a/crypto/key.go b/crypto/key.go index d371ad4dc..ca29b691f 100644 --- a/crypto/key.go +++ b/crypto/key.go @@ -57,7 +57,7 @@ type encryptedKeyJSON struct { func (k *Key) Address() []byte { pubBytes := FromECDSAPub(&k.PrivateKey.PublicKey) - return Sha3(pubBytes)[12:] + return Sha3(pubBytes[1:])[12:] } func (k *Key) MarshalJSON() (j []byte, err error) { @@ -99,9 +99,10 @@ func NewKey(rand io.Reader) *Key { privateKeyMarshalled := elliptic.Marshal(S256(), x, y) privateKeyECDSA := ToECDSA(privateKeyMarshalled) - key := new(Key) id := uuid.NewRandom() - key.Id = &id - key.PrivateKey = privateKeyECDSA + key := &Key{ + Id: &id, + PrivateKey: privateKeyECDSA, + } return key } diff --git a/crypto/key_store_passphrase.go b/crypto/key_store_passphrase.go index e30a0a785..913b68498 100644 --- a/crypto/key_store_passphrase.go +++ b/crypto/key_store_passphrase.go @@ -178,22 +178,10 @@ func DecryptKey(ks keyStorePassphrase, keyId *uuid.UUID, auth string) (keyBytes if err != nil { return nil, err } - - AES256Block, err := aes.NewCipher(derivedKey) + plainText, err := aes_cbc_decrypt(derivedKey, cipherText, iv) if err != nil { return nil, err } - - AES256CBCDecrypter := cipher.NewCBCDecrypter(AES256Block, iv) - paddedPlainText := make([]byte, len(cipherText)) - AES256CBCDecrypter.CryptBlocks(paddedPlainText, cipherText) - - plainText := PKCS7Unpad(paddedPlainText) - if plainText == nil { - err = errors.New("Decryption failed: PKCS7Unpad failed after decryption") - return nil, err - } - keyBytes = plainText[:len(plainText)-32] keyBytesHash := plainText[len(plainText)-32:] if !bytes.Equal(Sha3(keyBytes), keyBytesHash) { @@ -211,35 +199,3 @@ func getEntropyCSPRNG(n int) []byte { } return mainBuff } - -// From https://leanpub.com/gocrypto/read#leanpub-auto-block-cipher-modes -func PKCS7Pad(in []byte) []byte { - padding := 16 - (len(in) % 16) - if padding == 0 { - padding = 16 - } - for i := 0; i < padding; i++ { - in = append(in, byte(padding)) - } - return in -} - -func PKCS7Unpad(in []byte) []byte { - if len(in) == 0 { - return nil - } - - padding := in[len(in)-1] - if int(padding) > len(in) || padding > aes.BlockSize { - return nil - } else if padding == 0 { - return nil - } - - for i := len(in) - 1; i > len(in)-int(padding)-1; i-- { - if in[i] != padding { - return nil - } - } - return in[:len(in)-int(padding)] -} diff --git a/crypto/key_store_test.go b/crypto/key_store_test.go index 16c0e476d..54efc739a 100644 --- a/crypto/key_store_test.go +++ b/crypto/key_store_test.go @@ -83,3 +83,16 @@ func TestKeyStorePassphraseDecryptionFail(t *testing.T) { t.Fatal(err) } } + +func TestImportPreSaleKey(t *testing.T) { + // file content of a presale key file generated with: + // python pyethsaletool.py genwallet + // with password "foo" + fileContent := "{\"encseed\": \"26d87f5f2bf9835f9a47eefae571bc09f9107bb13d54ff12a4ec095d01f83897494cf34f7bed2ed34126ecba9db7b62de56c9d7cd136520a0427bfb11b8954ba7ac39b90d4650d3448e31185affcd74226a68f1e94b1108e6e0a4a91cdd83eba\", \"ethaddr\": \"d4584b5f6229b7be90727b0fc8c6b91bb427821f\", \"email\": \"gustav.simonsson@gmail.com\", \"btcaddr\": \"1EVknXyFC68kKNLkh6YnKzW41svSRoaAcx\"}" + ks := NewKeyStorePassphrase(DefaultDataDir()) + pass := "foo" + _, err := ImportPreSaleKey(ks, []byte(fileContent), pass) + if err != nil { + t.Fatal(err) + } +}