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-rw-r--r--internal/stupidgcm/common.go68
1 files changed, 68 insertions, 0 deletions
diff --git a/internal/stupidgcm/common.go b/internal/stupidgcm/common.go
new file mode 100644
index 0000000..3788315
--- /dev/null
+++ b/internal/stupidgcm/common.go
@@ -0,0 +1,68 @@
+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
+}