libgocryptfs/internal/stupidgcm/common.go
Jakob Unterwurzacher e2ec048a09 stupidgcm: introduce stupidAEADCommon and use for both chacha & gcm
Nice deduplication and brings the GCM decrypt speed up to par.

internal/speed$ benchstat old new
name                old time/op   new time/op   delta
StupidGCM-4          4.71µs ± 0%   4.66µs ± 0%   -0.99%  (p=0.008 n=5+5)
StupidGCMDecrypt-4   5.77µs ± 1%   4.51µs ± 0%  -21.80%  (p=0.008 n=5+5)

name                old speed     new speed     delta
StupidGCM-4         870MB/s ± 0%  879MB/s ± 0%   +1.01%  (p=0.008 n=5+5)
StupidGCMDecrypt-4  710MB/s ± 1%  908MB/s ± 0%  +27.87%  (p=0.008 n=5+5)
2021-09-07 18:14:05 +02:00

69 lines
1.5 KiB
Go

package stupidgcm
import (
"log"
)
/*
#include <openssl/evp.h>
*/
import "C"
type stupidAEADCommon struct {
wiped bool
key []byte
openSSLEVPCipher *C.EVP_CIPHER
nonceSize int
}
// Overhead returns the number of bytes that are added for authentication.
//
// Part of the cipher.AEAD interface.
func (c *stupidAEADCommon) Overhead() int {
return tagLen
}
// NonceSize returns the required size of the nonce / IV
//
// Part of the cipher.AEAD interface.
func (c *stupidAEADCommon) NonceSize() int {
return c.nonceSize
}
// Seal encrypts "in" using "iv" and "authData" and append the result to "dst"
//
// Part of the cipher.AEAD interface.
func (c *stupidAEADCommon) Seal(dst, iv, in, authData []byte) []byte {
return openSSLSeal(c, dst, iv, in, authData)
}
// Open decrypts "in" using "iv" and "authData" and append the result to "dst"
//
// Part of the cipher.AEAD interface.
func (c *stupidAEADCommon) Open(dst, iv, in, authData []byte) ([]byte, error) {
return openSSLOpen(c, dst, iv, in, authData)
}
// Wipe tries to wipe the key from memory by overwriting it with zeros.
//
// This is not bulletproof due to possible GC copies, but
// still raises the bar for extracting the key.
func (c *stupidAEADCommon) Wipe() {
key := c.key
c.wiped = true
c.key = nil
for i := range key {
key[i] = 0
}
}
func (c *stupidAEADCommon) Wiped() bool {
if c.wiped {
return true
}
if len(c.key) != keyLen {
log.Panicf("wrong key length %d", len(c.key))
}
return false
}