libs5-go/encoding/encrypted_cid.go

78 lines
2.0 KiB
Go

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 EncryptedCIDFromBytes(data)
}
func EncryptedCIDFromBytes(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
}