[Asterisk-Users] Voice Encryption

[Michael Jia]

Hi, Scott

The source code I found is in chan_iax.c, from the name of parameters, it
looks like it is using
AES. Can anyone here confirm that?

static int encrypt_frame(aes_encrypt_ctx *ecx, struct ast_iax2_full_hdr *fh,
unsigned char *poo, int *datalen)
{
int padding;
unsigned char *workspace;
workspace = alloca(*datalen + 32);
if (!workspace)
return -1;
if (ntohs(fh->scallno) & IAX_FLAG_FULL) {
struct ast_iax2_full_enc_hdr *efh = (struct ast_iax2_full_enc_hdr *)fh;
if (option_debug)
ast_log(LOG_DEBUG, "Encoding full frame with length %d\n", *datalen);
padding = 16 - ((*datalen - sizeof(struct ast_iax2_full_enc_hdr)) % 16);
padding = 16 + (padding & 0xf);
memcpy(workspace, poo, padding);
memcpy(workspace + padding, efh->encdata, *datalen - sizeof(struct
ast_iax2_full_enc_hdr));
*datalen += padding;
workspace[15] &= 0xf0;
workspace[15] |= (padding & 0xf);
memcpy_encrypt(efh->encdata, workspace, *datalen, ecx);
if (*datalen >= 32 + sizeof(struct ast_iax2_full_enc_hdr))
memcpy(poo, workspace + *datalen - 32, 32);
} else {
struct ast_iax2_mini_enc_hdr *efh = (struct ast_iax2_mini_enc_hdr *)fh;
if (option_debug)
ast_log(LOG_DEBUG, "Encoding mini frame with length %d\n", *datalen);
padding = 16 - ((*datalen - sizeof(struct ast_iax2_mini_enc_hdr)) % 16);
padding = 16 + (padding & 0xf);
memset(workspace, 0, padding);
memcpy(workspace + padding, efh->encdata, *datalen - sizeof(struct
ast_iax2_mini_enc_hdr));
workspace[15] &= 0xf0;
workspace[15] |= (padding & 0x0f);
*datalen += padding;
memcpy_encrypt(efh->encdata, workspace, *datalen, ecx);
if (*datalen >= 32 + sizeof(struct ast_iax2_mini_enc_hdr))
memcpy(poo, workspace + *datalen - 32, 32);
}
return 0;
}



On 9/28/05, tim panton <tpanton at attglobal.net> wrote:
>
>
> On 28 Sep 2005, at 07:26, Michael Jia wrote:
>
> Hi, Scott
>
> This is Michael Jia. So far, I searched the lists and with the following
> email threads
> http://lists.digium.com/pipermail/asterisk-dev/2004-December/008295.html
> I don't know what is the current working status now. Maybe somone in the
> lists
> knows.
>
>
> Last I heard IAX2 in CVS Head has encryption that works between 2 asterisk
> systems. There is no documentation (yet) except the source code, and no
> clients that support it (yet).
>
> Tim.
>
>
>
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