GCM mode and GCRY_CIPHER_AES256

[David Dahl]

Here is the code:
-----------------

#include "pbkdf2.h"

#define GCRY_CIPHER GCRY_CIPHER_AES256
#define GCRY_CIPHER_MODE GCRY_CIPHER_MODE_GCM
#define RNDM_BYTES_LENGTH 32
#define SALT_LENGTH 16

int wrapKeyItem (char* privateKey, struct keyItem key,
		 unsigned char name, struct wrappedKeyItem* out)
{
  size_t keyLength = gcry_cipher_get_algo_keylen(GCRY_CIPHER);
  size_t blkLength = gcry_cipher_get_algo_blklen(GCRY_CIPHER);
  size_t privateKeyLength = strlen(privateKey) + 1;
  char *encBuffer = malloc(privateKeyLength);
  gcry_error_t err = 0;

  // Create a handle
  gcry_cipher_hd_t handle;
  err = gcry_cipher_open(&handle, GCRY_CIPHER, GCRY_CIPHER_MODE, 0);
  if (!handle) {
    printf("GCM algo %d, gcry_cipher_open failed: %s\n",
	   GCRY_CIPHER, gpg_strerror (err));
    printf("Error no: %d and message: %s\n ", err, gcry_strerror(err));
    return 1;
  }
  // Set the key
  err = gcry_cipher_setkey(handle,
			   key.key,
			   keyLength);
  if (err) {
    printf("gcry_cipher_setkey failed.");
    printf("Error no: %d and message: %s\n ", err, gcry_strerror(err));
    return 1;
  }

  // set the IV
  unsigned int *iv;
  iv = gcry_random_bytes(RNDM_BYTES_LENGTH, GCRY_STRONG_RANDOM);
  err = gcry_cipher_setiv(handle, iv, blkLength);

  if (err) {
    printf("gcry_cipher_setiv failed.");
    printf("Error no: %d and message: %s\n ", err, gcry_strerror(err));
    return 1;
  }

  // Do encrypt
  err = gcry_cipher_encrypt(handle, encBuffer,
                            privateKeyLength, privateKey,
			    privateKeyLength);
  if (err) {
    printf("gcry_cipher_encrypt failed.");
    printf("Error no: %d and message: %s\n ", err, gcry_strerror(err));
    return 1;
  }

  printf("encBuffer: %s\n ", encBuffer);
  out->ciphertext = encBuffer;
  out->iv = iv;
  out->name = name;

  // Free memory
  gcry_cipher_close(handle);
  free(encBuffer);

  return 0;
}


On 05/30/2014 12:38 PM, Werner Koch wrote:
> On Fri, 30 May 2014 01:23, ddahl at nulltxt.se said:
> 
>> err = gcry_cipher_open(&handle, GCRY_CIPHER, GCRY_CIPHER_MODE, 0);
>>
>> returns with: "GCM algo 9, gcry_cipher_open failed: Invalid cipher mode"
> 
> Please paste the actual code so that we can understand and replicate the
> case.
>