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Switch the 64 bit hash implementation from 3DES to DES #5529

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Merged
sougou merged 1 commit into from
Dec 9, 2019
Merged

Switch the 64 bit hash implementation from 3DES to DES #5529

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12 changes: 7 additions & 5 deletions go/vt/vtgate/vindexes/hash.go
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Original file line number Diff line number Diff line change
Expand Up @@ -36,8 +36,10 @@ var (
)

// Hash defines vindex that hashes an int64 to a KeyspaceId
// by using null-key 3DES hash. It's Unique, Reversible and
// by using null-key DES hash. It's Unique, Reversible and
// Functional.
// Note that at once stage we used a 3DES-based hash here,
// but for a null key as in our case, they are completely equivalent.
type Hash struct {
name string
}
Expand Down Expand Up @@ -114,11 +116,11 @@ func (vind *Hash) ReverseMap(_ VCursor, ksids [][]byte) ([]sqltypes.Value, error
return reverseIds, nil
}

var block3DES cipher.Block
var blockDES cipher.Block

func init() {
var err error
block3DES, err = des.NewTripleDESCipher(make([]byte, 24))
blockDES, err = des.NewCipher(make([]byte, 8))
if err != nil {
panic(err)
}
Expand All @@ -128,7 +130,7 @@ func init() {
func vhash(shardKey uint64) []byte {
var keybytes, hashed [8]byte
binary.BigEndian.PutUint64(keybytes[:], shardKey)
block3DES.Encrypt(hashed[:], keybytes[:])
blockDES.Encrypt(hashed[:], keybytes[:])
return []byte(hashed[:])
}

Expand All @@ -137,6 +139,6 @@ func vunhash(k []byte) (uint64, error) {
return 0, fmt.Errorf("invalid keyspace id: %v", hex.EncodeToString(k))
}
var unhashed [8]byte
block3DES.Decrypt(unhashed[:], k)
blockDES.Decrypt(unhashed[:], k)
return binary.BigEndian.Uint64(unhashed[:]), nil
}