By default, don't use SRTP_AES128_CM_SHA1_32 protection profile.
This profile will now not be used unless the application explicitly
sets the flag in CryptoOptions to true. As a result, an 80-bit
authentication tag will be used instead of a 32-bit one. See bug for
more details.
Bug: webrtc:7670
Change-Id: I7c0a118fd7b1e7aac23b9eb8717099f055de0441
Reviewed-on: https://webrtc-review.googlesource.com/66600
Reviewed-by: Benjamin Wright <benwright@webrtc.org>
Reviewed-by: Peter Thatcher <pthatcher@webrtc.org>
Commit-Queue: Taylor Brandstetter <deadbeef@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22757}diff --git a/p2p/base/dtlstransport_unittest.cc b/p2p/base/dtlstransport_unittest.cc
index c66e02b..a8a8934 100644
--- a/p2p/base/dtlstransport_unittest.cc
+++ b/p2p/base/dtlstransport_unittest.cc
@@ -334,9 +334,9 @@
if (use_dtls_) {
// Check that we negotiated the right ciphers. Since GCM ciphers are not
- // negotiated by default, we should end up with SRTP_AES128_CM_SHA1_32.
- client1_.CheckSrtp(rtc::SRTP_AES128_CM_SHA1_32);
- client2_.CheckSrtp(rtc::SRTP_AES128_CM_SHA1_32);
+ // negotiated by default, we should end up with SRTP_AES128_CM_SHA1_80.
+ client1_.CheckSrtp(rtc::SRTP_AES128_CM_SHA1_80);
+ client2_.CheckSrtp(rtc::SRTP_AES128_CM_SHA1_80);
} else {
// If DTLS isn't actually being used, GetSrtpCryptoSuite should return
// false.
diff --git a/pc/mediasession_unittest.cc b/pc/mediasession_unittest.cc
index 8a0564a..c5194b9 100644
--- a/pc/mediasession_unittest.cc
+++ b/pc/mediasession_unittest.cc
@@ -213,6 +213,11 @@
"TCP/TLS/RTP/SAVPF", "TCP/TLS/RTP/SAVP", "UDP/TLS/RTP/SAVPF",
"UDP/TLS/RTP/SAVP"};
+// SRTP cipher name negotiated by the tests. This must be updated if the
+// default changes.
+static const char* kDefaultSrtpCryptoSuite = CS_AES_CM_128_HMAC_SHA1_80;
+static const char* kDefaultSrtpCryptoSuiteGcm = CS_AEAD_AES_256_GCM;
+
// These constants are used to make the code using "AddMediaSection" more
// readable.
static constexpr bool kStopped = true;
@@ -545,7 +550,7 @@
EXPECT_TRUE(CompareCryptoParams(audio_media_desc->cryptos(),
video_media_desc->cryptos()));
EXPECT_EQ(1u, audio_media_desc->cryptos().size());
- EXPECT_EQ(std::string(CS_AES_CM_128_HMAC_SHA1_80),
+ EXPECT_EQ(std::string(kDefaultSrtpCryptoSuite),
audio_media_desc->cryptos()[0].cipher_suite);
// Verify the selected crypto is one from the reference audio
@@ -636,18 +641,18 @@
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_TRUE(acd->rtcp_mux()); // negotiated rtcp-mux
if (gcm_offer && gcm_answer) {
- ASSERT_CRYPTO(acd, 1U, CS_AEAD_AES_256_GCM);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuiteGcm);
} else {
- ASSERT_CRYPTO(acd, 1U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
}
EXPECT_EQ(MEDIA_TYPE_VIDEO, vcd->type());
EXPECT_EQ(MAKE_VECTOR(kVideoCodecsAnswer), vcd->codecs());
EXPECT_EQ(0U, vcd->first_ssrc()); // no sender is attached
EXPECT_TRUE(vcd->rtcp_mux()); // negotiated rtcp-mux
if (gcm_offer && gcm_answer) {
- ASSERT_CRYPTO(vcd, 1U, CS_AEAD_AES_256_GCM);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuiteGcm);
} else {
- ASSERT_CRYPTO(vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuite);
}
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), vcd->protocol());
}
@@ -676,7 +681,7 @@
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached.
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(acd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(acd, 2U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), acd->protocol());
}
@@ -700,14 +705,14 @@
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(acd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(acd, 2U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), acd->protocol());
EXPECT_EQ(MEDIA_TYPE_VIDEO, vcd->type());
EXPECT_EQ(f1_.video_codecs(), vcd->codecs());
EXPECT_EQ(0U, vcd->first_ssrc()); // no sender is attached
EXPECT_EQ(kAutoBandwidth, vcd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(vcd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), vcd->protocol());
}
@@ -778,11 +783,11 @@
EXPECT_TRUE(NULL != acd);
EXPECT_TRUE(NULL != dcd);
- ASSERT_CRYPTO(acd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), acd->protocol());
- ASSERT_CRYPTO(vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), vcd->protocol());
- ASSERT_CRYPTO(dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), dcd->protocol());
}
@@ -807,7 +812,7 @@
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attched.
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(acd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(acd, 2U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), acd->protocol());
EXPECT_EQ(MEDIA_TYPE_DATA, dcd->type());
EXPECT_EQ(f1_.data_codecs(), dcd->codecs());
@@ -815,7 +820,7 @@
EXPECT_EQ(cricket::kDataMaxBandwidth,
dcd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(dcd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), dcd->protocol());
}
@@ -943,7 +948,7 @@
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // negotiated auto bw
EXPECT_TRUE(acd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(acd, 1U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), acd->protocol());
}
@@ -969,7 +974,7 @@
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // negotiated auto bw
EXPECT_TRUE(acd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(acd, 1U, CS_AEAD_AES_256_GCM);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuiteGcm);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), acd->protocol());
}
@@ -996,12 +1001,12 @@
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // negotiated auto bw
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_TRUE(acd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(acd, 1U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(MEDIA_TYPE_VIDEO, vcd->type());
EXPECT_EQ(MAKE_VECTOR(kVideoCodecsAnswer), vcd->codecs());
EXPECT_EQ(0U, vcd->first_ssrc()); // no sender is attached
EXPECT_TRUE(vcd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), vcd->protocol());
}
@@ -1045,12 +1050,12 @@
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // negotiated auto bw
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_TRUE(acd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(acd, 1U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(MEDIA_TYPE_DATA, dcd->type());
EXPECT_EQ(MAKE_VECTOR(kDataCodecsAnswer), dcd->codecs());
EXPECT_EQ(0U, dcd->first_ssrc()); // no sender is attached
EXPECT_TRUE(dcd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), dcd->protocol());
}
@@ -1077,12 +1082,12 @@
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // negotiated auto bw
EXPECT_EQ(0U, acd->first_ssrc()); // no sender is attached
EXPECT_TRUE(acd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(acd, 1U, CS_AEAD_AES_256_GCM);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuiteGcm);
EXPECT_EQ(MEDIA_TYPE_DATA, dcd->type());
EXPECT_EQ(MAKE_VECTOR(kDataCodecsAnswer), dcd->codecs());
EXPECT_EQ(0U, dcd->first_ssrc()); // no sender is attached
EXPECT_TRUE(dcd->rtcp_mux()); // negotiated rtcp-mux
- ASSERT_CRYPTO(dcd, 1U, CS_AEAD_AES_256_GCM);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuiteGcm);
EXPECT_EQ(std::string(cricket::kMediaProtocolSavpf), dcd->protocol());
}
@@ -1643,11 +1648,11 @@
EXPECT_EQ(kAutoBandwidth, acd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(acd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(acd, 2U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(MEDIA_TYPE_VIDEO, vcd->type());
EXPECT_EQ(f1_.video_codecs(), vcd->codecs());
- ASSERT_CRYPTO(vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuite);
const StreamParamsVec& video_streams = vcd->streams();
ASSERT_EQ(1U, video_streams.size());
@@ -1658,7 +1663,7 @@
EXPECT_EQ(MEDIA_TYPE_DATA, dcd->type());
EXPECT_EQ(f1_.data_codecs(), dcd->codecs());
- ASSERT_CRYPTO(dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuite);
const StreamParamsVec& data_streams = dcd->streams();
ASSERT_EQ(2U, data_streams.size());
@@ -1673,7 +1678,7 @@
EXPECT_EQ(cricket::kDataMaxBandwidth,
dcd->bandwidth()); // default bandwidth (auto)
EXPECT_TRUE(dcd->rtcp_mux()); // rtcp-mux defaults on
- ASSERT_CRYPTO(dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuite);
// Update the offer. Add a new video track that is not synched to the
// other tracks and replace audio track 2 with audio track 3.
@@ -1708,11 +1713,11 @@
EXPECT_EQ(vcd->codecs(), updated_vcd->codecs());
EXPECT_EQ(dcd->type(), updated_dcd->type());
EXPECT_EQ(dcd->codecs(), updated_dcd->codecs());
- ASSERT_CRYPTO(updated_acd, 2U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(updated_acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_TRUE(CompareCryptoParams(acd->cryptos(), updated_acd->cryptos()));
- ASSERT_CRYPTO(updated_vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(updated_vcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_TRUE(CompareCryptoParams(vcd->cryptos(), updated_vcd->cryptos()));
- ASSERT_CRYPTO(updated_dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(updated_dcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_TRUE(CompareCryptoParams(dcd->cryptos(), updated_dcd->cryptos()));
const StreamParamsVec& updated_audio_streams = updated_acd->streams();
@@ -1821,9 +1826,9 @@
const AudioContentDescription* acd = ac->media_description()->as_audio();
const VideoContentDescription* vcd = vc->media_description()->as_video();
const DataContentDescription* dcd = dc->media_description()->as_data();
- ASSERT_CRYPTO(acd, 1U, CS_AES_CM_128_HMAC_SHA1_32);
- ASSERT_CRYPTO(vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
- ASSERT_CRYPTO(dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(acd, 1U, kDefaultSrtpCryptoSuite);
+ ASSERT_CRYPTO(vcd, 1U, kDefaultSrtpCryptoSuite);
+ ASSERT_CRYPTO(dcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_EQ(MEDIA_TYPE_AUDIO, acd->type());
EXPECT_EQ(MAKE_VECTOR(kAudioCodecsAnswer), acd->codecs());
@@ -1891,11 +1896,11 @@
const DataContentDescription* updated_dcd =
dc->media_description()->as_data();
- ASSERT_CRYPTO(updated_acd, 1U, CS_AES_CM_128_HMAC_SHA1_32);
+ ASSERT_CRYPTO(updated_acd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_TRUE(CompareCryptoParams(acd->cryptos(), updated_acd->cryptos()));
- ASSERT_CRYPTO(updated_vcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(updated_vcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_TRUE(CompareCryptoParams(vcd->cryptos(), updated_vcd->cryptos()));
- ASSERT_CRYPTO(updated_dcd, 1U, CS_AES_CM_128_HMAC_SHA1_80);
+ ASSERT_CRYPTO(updated_dcd, 1U, kDefaultSrtpCryptoSuite);
EXPECT_TRUE(CompareCryptoParams(dcd->cryptos(), updated_dcd->cryptos()));
EXPECT_EQ(acd->type(), updated_acd->type());
@@ -2819,7 +2824,7 @@
ASSERT_TRUE(audio_media_desc != NULL);
video_media_desc = offer->GetContentDescriptionByName("video");
ASSERT_TRUE(video_media_desc != NULL);
- EXPECT_EQ(2u, audio_media_desc->cryptos().size());
+ EXPECT_EQ(1u, audio_media_desc->cryptos().size());
EXPECT_EQ(1u, video_media_desc->cryptos().size());
audio_trans_desc = offer->GetTransportDescriptionByName("audio");
diff --git a/pc/peerconnection_integrationtest.cc b/pc/peerconnection_integrationtest.cc
index d9cad53..f7ac830 100644
--- a/pc/peerconnection_integrationtest.cc
+++ b/pc/peerconnection_integrationtest.cc
@@ -114,7 +114,7 @@
// SRTP cipher name negotiated by the tests. This must be updated if the
// default changes.
-static const int kDefaultSrtpCryptoSuite = rtc::SRTP_AES128_CM_SHA1_32;
+static const int kDefaultSrtpCryptoSuite = rtc::SRTP_AES128_CM_SHA1_80;
static const int kDefaultSrtpCryptoSuiteGcm = rtc::SRTP_AEAD_AES_256_GCM;
static const SocketAddress kDefaultLocalAddress("192.168.1.1", 0);
diff --git a/pc/peerconnectioninterface_unittest.cc b/pc/peerconnectioninterface_unittest.cc
index 4728819..f702112 100644
--- a/pc/peerconnectioninterface_unittest.cc
+++ b/pc/peerconnectioninterface_unittest.cc
@@ -403,7 +403,7 @@
"a=fingerprint:sha-1 "
"4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:5D:49:6B:19:E5:7C:AB\r\n"
"a=setup:actpass\r\n"
- "a=crypto:1 AES_CM_128_HMAC_SHA1_32 "
+ "a=crypto:0 AES_CM_128_HMAC_SHA1_80 "
"inline:NzB4d1BINUAvLEw6UzF3WSJ+PSdFcGdUJShpX1Zj|2^20|1:32 "
"dummy_session_params\r\n";
diff --git a/pc/test/testsdpstrings.h b/pc/test/testsdpstrings.h
index ea9935c..ba139e2 100644
--- a/pc/test/testsdpstrings.h
+++ b/pc/test/testsdpstrings.h
@@ -92,7 +92,7 @@
"a=sendrecv\r\n"
"a=rtcp:16000 IN IP4 192.168.30.208\r\n"
"a=rtcp-mux\r\n"
- "a=crypto:1 AES_CM_128_HMAC_SHA1_80 "
+ "a=crypto:0 AES_CM_128_HMAC_SHA1_80 "
"inline:tvKIFjbMQ7W0/C2RzhwN0oQglj/7GJg+frdsNRxt\r\n"
"a=ice-ufrag:AI2sRT3r\r\n"
"a=ice-pwd:lByS9z2RSQlSE9XurlvjYmEm\r\n"
@@ -117,7 +117,7 @@
"a=sendrecv\r\n"
"a=rtcp:16000 IN IP4 192.168.30.208\r\n"
"a=rtcp-mux\r\n"
- "a=crypto:1 AES_CM_128_HMAC_SHA1_80 "
+ "a=crypto:0 AES_CM_128_HMAC_SHA1_80 "
"inline:tvKIFjbMQ7W0/C2RzhwN0oQglj/7GJg+frdsNRxt\r\n"
"a=ice-ufrag:AI2sRT3r\r\n"
"a=ice-pwd:lByS9z2RSQlSE9XurlvjYmEm\r\n"
@@ -142,7 +142,7 @@
"a=sendonly\r\n"
"a=rtcp:16000 IN IP4 192.168.30.208\r\n"
"a=rtcp-mux\r\n"
- "a=crypto:1 AES_CM_128_HMAC_SHA1_80 "
+ "a=crypto:0 AES_CM_128_HMAC_SHA1_80 "
"inline:tvKIFjbMQ7W0/C2RzhwN0oQglj/7GJg+frdsNRxt\r\n"
"a=ice-ufrag:AI2sRT3r\r\n"
"a=ice-pwd:lByS9z2RSQlSE9XurlvjYmEm\r\n"
@@ -169,7 +169,7 @@
"a=sendonly\r\n"
"a=rtcp:16000 IN IP4 192.168.30.208\r\n"
"a=rtcp-mux\r\n"
- "a=crypto:1 AES_CM_128_HMAC_SHA1_80 "
+ "a=crypto:0 AES_CM_128_HMAC_SHA1_80 "
"inline:tvKIFjbMQ7W0/C2RzhwN0oQglj/7GJg+frdsNRxt\r\n"
"a=ice-ufrag:AI2sRT3r\r\n"
"a=ice-pwd:lByS9z2RSQlSE9XurlvjYmEm\r\n"
diff --git a/rtc_base/sslstreamadapter.h b/rtc_base/sslstreamadapter.h
index 11a67e4..827dc45 100644
--- a/rtc_base/sslstreamadapter.h
+++ b/rtc_base/sslstreamadapter.h
@@ -84,10 +84,7 @@
// SRTP_AES128_CM_SHA1_32 will be included in the list of supported ciphers
// during negotiation. It will only be used if both peers support it and no
// other ciphers get preferred.
- // TODO(crbug.com/webrtc/7670): Change default to false after sending PSA and
- // giving time for users to set this flag to true explicitly, if they still
- // want to use this crypto suite.
- bool enable_aes128_sha1_32_crypto_cipher = true;
+ bool enable_aes128_sha1_32_crypto_cipher = false;
// If set to true, encrypted RTP header extensions as defined in RFC 6904
// will be negotiated. They will only be used if both peers support them.
