mirror of
https://github.com/slackhq/nebula.git
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75 lines
2 KiB
Go
75 lines
2 KiB
Go
package nebula
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import (
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"crypto/cipher"
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"encoding/binary"
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"errors"
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"github.com/flynn/noise"
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)
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type endianness interface {
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PutUint64(b []byte, v uint64)
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}
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var noiseEndianness endianness = binary.BigEndian
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type NebulaCipherState struct {
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c noise.Cipher
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//k [32]byte
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//n uint64
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}
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func NewNebulaCipherState(s *noise.CipherState) *NebulaCipherState {
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return &NebulaCipherState{c: s.Cipher()}
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}
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// EncryptDanger encrypts and authenticates a given payload.
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//
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// out is a destination slice to hold the output of the EncryptDanger operation.
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// - ad is additional data, which will be authenticated and appended to out, but not encrypted.
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// - plaintext is encrypted, authenticated and appended to out.
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// - n is a nonce value which must never be re-used with this key.
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// - nb is a buffer used for temporary storage in the implementation of this call, which should
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// be re-used by callers to minimize garbage collection.
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func (s *NebulaCipherState) EncryptDanger(out, ad, plaintext []byte, n uint64, nb []byte) ([]byte, error) {
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if s != nil {
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// TODO: Is this okay now that we have made messageCounter atomic?
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// Alternative may be to split the counter space into ranges
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//if n <= s.n {
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// return nil, errors.New("CRITICAL: a duplicate counter value was used")
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//}
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//s.n = n
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nb[0] = 0
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nb[1] = 0
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nb[2] = 0
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nb[3] = 0
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noiseEndianness.PutUint64(nb[4:], n)
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out = s.c.(cipher.AEAD).Seal(out, nb, plaintext, ad)
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//l.Debugf("Encryption: outlen: %d, nonce: %d, ad: %s, plainlen %d", len(out), n, ad, len(plaintext))
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return out, nil
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} else {
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return nil, errors.New("no cipher state available to encrypt")
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}
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}
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func (s *NebulaCipherState) DecryptDanger(out, ad, ciphertext []byte, n uint64, nb []byte) ([]byte, error) {
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if s != nil {
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nb[0] = 0
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nb[1] = 0
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nb[2] = 0
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nb[3] = 0
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noiseEndianness.PutUint64(nb[4:], n)
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return s.c.(cipher.AEAD).Open(out, nb, ciphertext, ad)
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} else {
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return []byte{}, nil
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}
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}
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func (s *NebulaCipherState) Overhead() int {
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if s != nil {
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return s.c.(cipher.AEAD).Overhead()
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}
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return 0
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}
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