--- channels/chan_iax2.c.orig	2021-05-06 15:34:57.000000000 +0000
+++ channels/chan_iax2.c	2021-05-18 21:58:44.689000238 +0000
@@ -8374,6 +8374,18 @@
 					res = 0;
 				}
 			}
+
+			if (pvt && !ast_strlen_zero(secret)) {
+				struct MD5Context md5;
+				unsigned char digest[16];
+
+				MD5Init(&md5);
+				MD5Update(&md5, (unsigned char *) challenge, strlen(challenge));
+				MD5Update(&md5, (unsigned char *) secret, strlen(secret));
+				MD5Final(digest, &md5);
+
+				build_encryption_keys(digest, pvt);
+			}
 		}
 	}
 	/* Fall back */
@@ -10942,8 +10954,8 @@
 					}
 					break;
 				}
-				if (iaxs[fr->callno]->authmethods & IAX_AUTH_MD5)
-					merge_encryption(iaxs[fr->callno],ies.encmethods);
+				if (iaxs[fr->callno]->authmethods & (IAX_AUTH_MD5 | IAX_AUTH_RSA))
+					merge_encryption(iaxs[fr->callno], ies.encmethods);
 				else
 					iaxs[fr->callno]->encmethods = 0;
 				if (!authenticate_request(fr->callno) && iaxs[fr->callno])