libgocryptfs/internal/stupidgcm/common.go

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
}