169 lines
7.4 KiB
Objective-C
169 lines
7.4 KiB
Objective-C
#import "MasterSecret.h"
|
|
#import "Conversions.h"
|
|
#import "CryptoTools.h"
|
|
#import "ShortAuthenticationStringGenerator.h"
|
|
#import "Util.h"
|
|
|
|
#define INITIATOR_SRTP_KEY_LABEL @"Initiator SRTP master key"
|
|
#define RESPONDER_SRTP_KEY_LABEL @"Responder SRTP master key"
|
|
#define INITIATOR_SRTP_SALT_LABEL @"Initiator SRTP master salt"
|
|
#define RESPONDER_SRTP_SALT_LABEL @"Responder SRTP master salt"
|
|
#define INITIATOR_MAC_KEY_LABEL @"Initiator HMAC key"
|
|
#define RESPONDER_MAC_KEY_LABEL @"Responder HMAC key"
|
|
#define INITIATOR_ZRTP_KEY_LABEL @"Initiator ZRTP key"
|
|
#define RESPONDER_ZRTP_KEY_LABEL @"Responder ZRTP key"
|
|
#define SAS_LABEL @"SAS"
|
|
|
|
#define INITIATOR_SRTP_KEY_LENGTH 16
|
|
#define RESPONDER_SRTP_KEY_LENGTH 16
|
|
#define INITIATOR_SRTP_SALT_LENGTH 14
|
|
#define RESPONDER_SRTP_SALT_LENGTH 14
|
|
#define INITIATOR_MAC_KEY_LENGTH 20
|
|
#define RESPONDER_MAC_KEY_LENGTH 20
|
|
#define INITIATOR_ZRTP_KEY_LENGTH 16
|
|
#define RESPONDER_ZRTP_KEY_LENGTH 16
|
|
#define SAS_LENGTH 4
|
|
|
|
@implementation MasterSecret
|
|
|
|
@synthesize initiatorMacKey, initiatorSrtpSalt, initiatorZrtpKey, initiatorSrtpKey, initiatorZid,
|
|
responderMacKey, responderSrtpSalt, responderZrtpKey, responderSrtpKey, responderZid,
|
|
shortAuthenticationStringData, sharedSecret, totalHash, counter;
|
|
|
|
+(MasterSecret*) masterSecretFromDhResult:(NSData*)dhResult
|
|
andInitiatorHello:(HelloPacket*)initiatorHello
|
|
andResponderHello:(HelloPacket*)responderHello
|
|
andCommit:(CommitPacket*)commit
|
|
andDhPart1:(DhPacket*)dhPart1
|
|
andDhPart2:(DhPacket*)dhPart2 {
|
|
require(dhResult != nil);
|
|
require(initiatorHello != nil);
|
|
require(responderHello != nil);
|
|
require(commit != nil);
|
|
require(dhPart1 != nil);
|
|
require(dhPart2 != nil);
|
|
|
|
NSData* totalHash = [self calculateTotalHashFromResponderHello:responderHello
|
|
andCommit:commit
|
|
andDhPart1:dhPart1
|
|
andDhPart2:dhPart2];
|
|
|
|
NSData* sharedSecret = [self calculateSharedSecretFromDhResult:dhResult
|
|
andTotalHash:totalHash
|
|
andInitiatorZid:[initiatorHello zid]
|
|
andResponderZid:[responderHello zid]];
|
|
|
|
return [MasterSecret masterSecretFromSharedSecret:sharedSecret
|
|
andTotalHash:totalHash
|
|
andInitiatorZid:[initiatorHello zid]
|
|
andResponderZid:[responderHello zid]];
|
|
|
|
}
|
|
|
|
+(NSData*) calculateSharedSecretFromDhResult:(NSData*)dhResult
|
|
andTotalHash:(NSData*)totalHash
|
|
andInitiatorZid:(Zid*)initiatorZid
|
|
andResponderZid:(Zid*)responderZid {
|
|
require(dhResult != nil);
|
|
require(totalHash != nil);
|
|
require(initiatorZid != nil);
|
|
require(responderZid != nil);
|
|
|
|
NSData* counter = [NSData dataWithBigEndianBytesOfUInt32:1];
|
|
NSData* s1Length = [NSData dataWithBigEndianBytesOfUInt32:0];
|
|
NSData* s2Length = [NSData dataWithBigEndianBytesOfUInt32:0];
|
|
NSData* s3Length = [NSData dataWithBigEndianBytesOfUInt32:0];
|
|
|
|
NSData* data = [@[
|
|
|
|
counter,
|
|
dhResult,
|
|
@"ZRTP-HMAC-KDF".encodedAsUtf8,
|
|
initiatorZid.getData,
|
|
responderZid.getData,
|
|
totalHash,
|
|
s1Length,
|
|
s2Length,
|
|
s3Length
|
|
|
|
] concatDatas];
|
|
|
|
return [data hashWithSha256];
|
|
}
|
|
|
|
+(NSData*) calculateTotalHashFromResponderHello:(HelloPacket*)responderHello
|
|
andCommit:(CommitPacket*)commit
|
|
andDhPart1:(DhPacket*)dhPart1
|
|
andDhPart2:(DhPacket*)dhPart2 {
|
|
require(responderHello != nil);
|
|
require(commit != nil);
|
|
require(dhPart1 != nil);
|
|
require(dhPart2 != nil);
|
|
|
|
NSData* data = [@[
|
|
|
|
[[responderHello embeddedIntoHandshakePacket] dataUsedForAuthentication],
|
|
[[commit embeddedIntoHandshakePacket] dataUsedForAuthentication],
|
|
[[dhPart1 embeddedIntoHandshakePacket] dataUsedForAuthentication],
|
|
[[dhPart2 embeddedIntoHandshakePacket] dataUsedForAuthentication]
|
|
|
|
] concatDatas];
|
|
|
|
return [data hashWithSha256];
|
|
|
|
}
|
|
|
|
+(MasterSecret*) masterSecretFromSharedSecret:(NSData*)sharedSecret
|
|
andTotalHash:(NSData*)totalHash
|
|
andInitiatorZid:(Zid*)initiatorZid
|
|
andResponderZid:(Zid*)responderZid {
|
|
require(sharedSecret != nil);
|
|
require(totalHash != nil);
|
|
require(initiatorZid != nil);
|
|
require(responderZid != nil);
|
|
|
|
MasterSecret* s = [MasterSecret new];
|
|
|
|
s->initiatorZid = initiatorZid;
|
|
s->responderZid = responderZid;
|
|
s->totalHash = totalHash;
|
|
s->sharedSecret = sharedSecret;
|
|
s->counter = [NSData dataWithBigEndianBytesOfUInt32:1];
|
|
|
|
s->initiatorSrtpKey = [s deriveKeyWithLabel:INITIATOR_SRTP_KEY_LABEL andTruncatedLength:INITIATOR_SRTP_KEY_LENGTH];
|
|
s->responderSrtpKey = [s deriveKeyWithLabel:RESPONDER_SRTP_KEY_LABEL andTruncatedLength:RESPONDER_SRTP_KEY_LENGTH];
|
|
s->initiatorSrtpSalt = [s deriveKeyWithLabel:INITIATOR_SRTP_SALT_LABEL andTruncatedLength:INITIATOR_SRTP_SALT_LENGTH];
|
|
s->responderSrtpSalt = [s deriveKeyWithLabel:RESPONDER_SRTP_SALT_LABEL andTruncatedLength:RESPONDER_SRTP_SALT_LENGTH];
|
|
s->initiatorMacKey = [s deriveKeyWithLabel:INITIATOR_MAC_KEY_LABEL andTruncatedLength:INITIATOR_MAC_KEY_LENGTH];
|
|
s->responderMacKey = [s deriveKeyWithLabel:RESPONDER_MAC_KEY_LABEL andTruncatedLength:RESPONDER_MAC_KEY_LENGTH];
|
|
s->initiatorZrtpKey = [s deriveKeyWithLabel:INITIATOR_ZRTP_KEY_LABEL andTruncatedLength:INITIATOR_ZRTP_KEY_LENGTH];
|
|
s->responderZrtpKey = [s deriveKeyWithLabel:RESPONDER_ZRTP_KEY_LABEL andTruncatedLength:RESPONDER_ZRTP_KEY_LENGTH];
|
|
s->shortAuthenticationStringData = [s deriveKeyWithLabel:SAS_LABEL andTruncatedLength:SAS_LENGTH];
|
|
|
|
return s;
|
|
}
|
|
|
|
-(NSData*) deriveKeyWithLabel:(NSString*)label andTruncatedLength:(uint16_t)truncatedLength {
|
|
NSData* input = @[
|
|
|
|
counter,
|
|
label.encodedAsUtf8,
|
|
[@[@0] toUint8Data],
|
|
initiatorZid.getData,
|
|
responderZid.getData,
|
|
totalHash,
|
|
[NSData dataWithBigEndianBytesOfUInt32:truncatedLength]
|
|
|
|
].concatDatas;
|
|
|
|
NSData* digest = [input hmacWithSha256WithKey:sharedSecret];
|
|
|
|
return [digest take:truncatedLength];
|
|
}
|
|
|
|
-(NSString*) shortAuthenticationString {
|
|
return [ShortAuthenticationStringGenerator generateFromData:shortAuthenticationStringData];
|
|
}
|
|
|
|
@end
|