mirror of https://github.com/status-im/megolm.git
115 lines
2.2 KiB
Go
115 lines
2.2 KiB
Go
package main
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/hmac"
|
|
"crypto/sha256"
|
|
"errors"
|
|
|
|
"golang.org/x/crypto/hkdf"
|
|
)
|
|
|
|
func deriveKeys(input []byte, salt []byte, info []byte) (*DerivedKeys, error) {
|
|
h := hkdf.New(sha256.New, input, salt, info)
|
|
|
|
keys := &DerivedKeys{
|
|
aesKey: make([]byte, AES256_KEY_LENGTH),
|
|
macKey: make([]byte, HMAC_KEY_LENGTH),
|
|
aesIV: make([]byte, AES256_IV_LENGTH),
|
|
}
|
|
|
|
if _, err := h.Read(keys.aesKey); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if _, err := h.Read(keys.macKey); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if _, err := h.Read(keys.aesIV); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return keys, nil
|
|
}
|
|
|
|
func pkcs7Pad(data []byte, blocksize int) ([]byte, error) {
|
|
if blocksize <= 0 {
|
|
return nil, errors.New("ErrInvalidBlockSize")
|
|
}
|
|
|
|
if data == nil || len(data) == 0 {
|
|
return nil, errors.New("ErrInvalidPKCS7Data")
|
|
}
|
|
|
|
padLen := blocksize - len(data)%blocksize
|
|
padding := bytes.Repeat([]byte{byte(padLen)}, padLen)
|
|
|
|
return append(data, padding...), nil
|
|
}
|
|
|
|
func pkcs7Unpad(data []byte, blocksize int) ([]byte, error) {
|
|
if blocksize <= 0 {
|
|
return nil, errors.New("ErrInvalidBlockSize")
|
|
}
|
|
|
|
if data == nil || len(data) == 0 {
|
|
return nil, errors.New("ErrInvalidPKCS7Data")
|
|
}
|
|
|
|
if len(data)%blocksize != 0 {
|
|
return nil, errors.New("ErrInvalidPKCS7Padding")
|
|
}
|
|
|
|
c := data[len(data)-1]
|
|
n := int(c)
|
|
|
|
if n == 0 || n > len(data) {
|
|
return nil, errors.New("ErrInvalidPKCS7Padding")
|
|
}
|
|
|
|
for i := 0; i < n; i++ {
|
|
if data[len(data)-n+i] != c {
|
|
return nil, errors.New("ErrInvalidPKCS7Padding")
|
|
}
|
|
}
|
|
|
|
return data[:len(data)-n], nil
|
|
}
|
|
|
|
func generateHMACKey(inputKey []byte) []byte {
|
|
hmacKey := make([]byte, SHA256_BLOCK_LENGTH)
|
|
if len(inputKey) > SHA256_BLOCK_LENGTH {
|
|
// TODO: check this part
|
|
h := sha256.New()
|
|
h.Write(inputKey)
|
|
res := h.Sum(nil)
|
|
copy(hmacKey, res)
|
|
} else {
|
|
copy(hmacKey, inputKey)
|
|
}
|
|
|
|
return hmacKey
|
|
}
|
|
|
|
func HMACSHA256(key []byte, input []byte) []byte {
|
|
hmacKey := generateHMACKey(key)
|
|
ctx := hmac.New(sha256.New, hmacKey)
|
|
ctx.Write(input)
|
|
return ctx.Sum(nil)
|
|
}
|
|
|
|
func uvarintLen(x uint64) uint64 {
|
|
var res uint64 = 1
|
|
for x >= 0x80 {
|
|
res++
|
|
x >>= 7
|
|
}
|
|
|
|
return res
|
|
}
|
|
|
|
func varStringLen(n uint64) uint64 {
|
|
return uvarintLen(n) + n
|
|
}
|