func createKey(mh multihash.Multihash, prefixLen int) multihash.Multihash {
// Grab the first 8 bytes from the multihash digest
m, _ := multihash.Decode(mh)
prefix64 := binary.BigEndian.Uint64(m.Digest[:8])
// Convert to binary string
bin := strconv.FormatUint(prefix64, 2)
// Pad with leading zeros
leadingZeros := 64 - len(bin)
for i := 0; i < leadingZeros; i++ {
bin = "0" + bin
}
// Grab the bits corresponding to the prefix length and convert to int
intPrefix, _ := strconv.ParseUint(bin[:prefixLen], 2, 64)
// Convert to 8 byte array
bs := make([]byte, 8)
binary.BigEndian.PutUint64(bs, intPrefix)
// Hash the array
hash := sha256.New()
hash.Write(bs)
md := hash.Sum(nil)
// Encode as multihash
keyHash, _ := multihash.Encode(md, multihash.SHA2_256)
return keyHash
}
func getMagicID() (peer.ID, error) {
magicBytes, err := hex.DecodeString(MAGIC)
if err != nil {
return "", err
}
randBytes := make([]byte, 20)
rand.Read(randBytes)
magicBytes = append(magicBytes, randBytes[:]...)
h, err := multihash.Encode(magicBytes, multihash.SHA2_256)
if err != nil {
return "", err
}
id, err := peer.IDFromBytes(h)
if err != nil {
return "", err
}
return id, nil
}
func (s *DropBoxStorage) Store(peerID peer.ID, ciphertext []byte) (ma.Multiaddr, error) {
api := dropbox.Client(s.apiToken, dropbox.Options{Verbose: true})
hash := sha256.Sum256(ciphertext)
hex := hex.EncodeToString(hash[:])
// Upload ciphertext
uploadArg := files.NewCommitInfo("/" + hex)
r := bytes.NewReader(ciphertext)
_, err := api.Upload(uploadArg, r)
if err != nil {
return nil, err
}
// Set public sharing
sharingArg := sharing.NewCreateSharedLinkArg("/" + hex)
res, err := api.CreateSharedLink(sharingArg)
if err != nil {
return nil, err
}
// Create encoded multiaddr
url := res.Url[:len(res.Url)-1] + "1"
b, err := mh.Encode([]byte(url), mh.SHA1)
if err != nil {
return nil, err
}
m, err := mh.Cast(b)
if err != nil {
return nil, err
}
addr, err := ma.NewMultiaddr("/ipfs/" + m.B58String() + "/https/")
if err != nil {
return nil, err
}
return addr, nil
}
