libgocryptfs/internal/stupidgcm/gcm.go

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// +build !without_openssl
// Package stupidgcm is a thin wrapper for OpenSSL's GCM encryption and
// decryption functions. It only support 32-byte keys and 16-bit IVs.
package stupidgcm
// #include <openssl/evp.h>
import "C"
import (
"crypto/cipher"
"log"
)
const (
// BuiltWithoutOpenssl indicates if openssl been disabled at compile-time
BuiltWithoutOpenssl = false
keyLen = 32
ivLen = 16
tagLen = 16
)
type stupidGCM struct {
stupidAEADCommon
}
// Verify that we satisfy the interface
var _ cipher.AEAD = &stupidGCM{}
// New returns a new cipher.AEAD implementation..
func New(keyIn []byte, forceDecode bool) cipher.AEAD {
if len(keyIn) != keyLen {
log.Panicf("Only %d-byte keys are supported", keyLen)
}
return &stupidGCM{
stupidAEADCommon{
// Create a private copy of the key
key: append([]byte{}, keyIn...),
openSSLEVPCipher: C.EVP_aes_256_gcm(),
nonceSize: ivLen,
},
}
}