diff --git a/encoding/encrypted_cid.go b/encoding/encrypted_cid.go new file mode 100644 index 0000000..673912e --- /dev/null +++ b/encoding/encrypted_cid.go @@ -0,0 +1,77 @@ +package encoding + +import ( + "errors" + "git.lumeweb.com/LumeWeb/libs5-go/types" + "git.lumeweb.com/LumeWeb/libs5-go/utils" +) + +type EncryptedCID struct { + Multibase + encryptedBlobHash Multihash + originalCID CID + encryptionAlgorithm byte + padding uint32 + chunkSizeAsPowerOf2 int + encryptionKey []byte +} + +func NewEncryptedCID(encryptedBlobHash Multihash, originalCID CID, encryptionKey []byte, padding uint32, chunkSizeAsPowerOf2 int, encryptionAlgorithm byte) *EncryptedCID { + e := &EncryptedCID{ + encryptedBlobHash: encryptedBlobHash, + originalCID: originalCID, + encryptionKey: encryptionKey, + padding: padding, + chunkSizeAsPowerOf2: chunkSizeAsPowerOf2, + encryptionAlgorithm: encryptionAlgorithm, + } + + m := NewMultibase(e) + e.Multibase = m + + return e +} + +func DecodeEncryptedCID(cid string) (*EncryptedCID, error) { + data, err := MultibaseDecodeString(cid) + if err != nil { + return nil, err + } + return FromBytes(data) +} + +func FromBytes(data []byte) (*EncryptedCID, error) { + if types.CIDType(data[0]) != types.CIDTypeEncryptedStatic { + return nil, errors.New("Invalid CID type") + } + + cid, err := CIDFromBytes(data[72:]) + if err != nil { + return nil, err + } + + encryptedBlobHash := NewMultihash(data[3:36]) + encryptionKey := data[36:68] + padding := utils.DecodeEndian(data[68:72]) + chunkSizeAsPowerOf2 := int(data[2]) + encryptionAlgorithm := data[1] + + return NewEncryptedCID(*encryptedBlobHash, *cid, encryptionKey, padding, chunkSizeAsPowerOf2, encryptionAlgorithm), nil +} + +func (c *EncryptedCID) ChunkSize() int { + return 1 << uint(c.chunkSizeAsPowerOf2) +} + +func (c *EncryptedCID) ToBytes() []byte { + data := []byte{ + byte(types.CIDTypeEncryptedStatic), + c.encryptionAlgorithm, + byte(c.chunkSizeAsPowerOf2), + } + data = append(data, c.encryptedBlobHash.FullBytes...) + data = append(data, c.encryptionKey...) + data = append(data, utils.EncodeEndian(c.padding, 4)...) + data = append(data, c.originalCID.ToBytes()...) + return data +}