forked from mjosaarinen/blake2_mjosref
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathrfc7693.txt
1626 lines (1068 loc) · 54.1 KB
/
rfc7693.txt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
Independent Submission M-J. Saarinen, Ed.
Request for Comments: 7693 Queen's University Belfast
Category: Informational J-P. Aumasson
ISSN: 2070-1721 Kudelski Security
November 2015
The BLAKE2 Cryptographic Hash and Message Authentication Code (MAC)
Abstract
This document describes the cryptographic hash function BLAKE2 and
makes the algorithm specification and C source code conveniently
available to the Internet community. BLAKE2 comes in two main
flavors: BLAKE2b is optimized for 64-bit platforms and BLAKE2s for
smaller architectures. BLAKE2 can be directly keyed, making it
functionally equivalent to a Message Authentication Code (MAC).
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This is a contribution to the RFC Series, independently of any other
RFC stream. The RFC Editor has chosen to publish this document at
its discretion and makes no statement about its value for
implementation or deployment. Documents approved for publication by
the RFC Editor are not a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7693.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Saarinen & Aumasson Informational [Page 1]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
Table of Contents
1. Introduction and Terminology . . . . . . . . . . . . . . . . 2
2. Conventions, Variables, and Constants . . . . . . . . . . . . 3
2.1. Parameters . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Other Constants and Variables . . . . . . . . . . . . . . 4
2.3. Arithmetic Notation . . . . . . . . . . . . . . . . . . . 4
2.4. Little-Endian Interpretation of Words as Bytes . . . . . 5
2.5. Parameter Block . . . . . . . . . . . . . . . . . . . . . 5
2.6. Initialization Vector . . . . . . . . . . . . . . . . . . 5
2.7. Message Schedule SIGMA . . . . . . . . . . . . . . . . . 6
3. BLAKE2 Processing . . . . . . . . . . . . . . . . . . . . . . 6
3.1. Mixing Function G . . . . . . . . . . . . . . . . . . . . 6
3.2. Compression Function F . . . . . . . . . . . . . . . . . 7
3.3. Padding Data and Computing a BLAKE2 Digest . . . . . . . 8
4. Standard Parameter Sets and Algorithm Identifiers . . . . . . 9
5. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Normative References . . . . . . . . . . . . . . . . . . 10
6.2. Informative References . . . . . . . . . . . . . . . . . 11
Appendix A. Example of BLAKE2b Computation . . . . . . . . . . . 11
Appendix B. Example of BLAKE2s Computation . . . . . . . . . . . 13
Appendix C. BLAKE2b Implementation C Source . . . . . . . . . . 15
C.1. blake2b.h . . . . . . . . . . . . . . . . . . . . . . . . 15
C.2. blake2b.c . . . . . . . . . . . . . . . . . . . . . . . . 16
Appendix D. BLAKE2s Implementation C Source . . . . . . . . . . 20
D.1. blake2s.h . . . . . . . . . . . . . . . . . . . . . . . . 20
D.2. blake2s.c . . . . . . . . . . . . . . . . . . . . . . . . 21
Appendix E. BLAKE2b and BLAKE2s Self-Test Module C Source . . . 25
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 29
1. Introduction and Terminology
The BLAKE2 cryptographic hash function [BLAKE2] was designed by Jean-
Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn, and Christian
Winnerlein.
BLAKE2 comes in two basic flavors:
o BLAKE2b (or just BLAKE2) is optimized for 64-bit platforms and
produces digests of any size between 1 and 64 bytes.
o BLAKE2s is optimized for 8- to 32-bit platforms and produces
digests of any size between 1 and 32 bytes.
Both BLAKE2b and BLAKE2s are believed to be highly secure and perform
well on any platform, software, or hardware. BLAKE2 does not require
Saarinen & Aumasson Informational [Page 2]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
a special "HMAC" (Hashed Message Authentication Code) construction
for keyed message authentication as it has a built-in keying
mechanism.
The BLAKE2 hash function may be used by digital signature algorithms
and message authentication and integrity protection mechanisms in
applications such as Public Key Infrastructure (PKI), secure
communication protocols, cloud storage, intrusion detection, forensic
suites, and version control systems.
The BLAKE2 suite provides a more efficient alternative to US Secure
Hash Algorithms SHA and HMAC-SHA [RFC6234]. BLAKE2s-128 is
especially suited as a fast and more secure drop-in replacement to
MD5 and HMAC-MD5 in legacy applications [RFC6151].
To aid implementation, we provide a trace of BLAKE2b-512 hash
computation in Appendix A and a trace of BLAKE2s-256 hash computation
in Appendix B. Due to space constraints, this document does not
contain a full set of test vectors for BLAKE2.
A reference implementation in C programming language for BLAKE2b can
be found in Appendix C and for BLAKE2s in Appendix D of this
document. These implementations MAY be validated with the more
exhaustive Test Module contained in Appendix E.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Conventions, Variables, and Constants
2.1. Parameters
The following table summarizes various parameters and their ranges:
| BLAKE2b | BLAKE2s |
--------------+------------------+------------------+
Bits in word | w = 64 | w = 32 |
Rounds in F | r = 12 | r = 10 |
Block bytes | bb = 128 | bb = 64 |
Hash bytes | 1 <= nn <= 64 | 1 <= nn <= 32 |
Key bytes | 0 <= kk <= 64 | 0 <= kk <= 32 |
Input bytes | 0 <= ll < 2**128 | 0 <= ll < 2**64 |
--------------+------------------+------------------+
G Rotation | (R1, R2, R3, R4) | (R1, R2, R3, R4) |
constants = | (32, 24, 16, 63) | (16, 12, 8, 7) |
--------------+------------------+------------------+
Saarinen & Aumasson Informational [Page 3]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
2.2. Other Constants and Variables
These variables are used in the algorithm description:
IV[0..7] Initialization Vector (constant).
SIGMA[0..9] Message word permutations (constant).
p[0..7] Parameter block (defines hash and key sizes).
m[0..15] Sixteen words of a single message block.
h[0..7] Internal state of the hash.
d[0..dd-1] Padded input blocks. Each has "bb" bytes.
t Message byte offset at the end of the current block.
f Flag indicating the last block.
2.3. Arithmetic Notation
For real-valued x, we define the following functions:
floor(x) Floor, the largest integer <= x.
ceil(x) Ceiling, the smallest integer >= x.
frac(x) Positive fractional part of x, frac(x) = x - floor(x).
Operator notation in pseudocode:
2**n = 2 to the power "n". 2**0=1, 2**1=2, 2**2=4, 2**3=8, etc.
a ^ b = Bitwise exclusive-or operation between "a" and "b".
a mod b = Remainder "a" modulo "b", always in range [0, b-1].
x >> n = floor(x / 2**n). Logical shift "x" right by "n" bits.
x << n = (x * 2**n) mod (2**w). Logical shift "x" left by "n".
x >>> n = (x >> n) ^ (x << (w - n)). Rotate "x" right by "n".
Saarinen & Aumasson Informational [Page 4]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
2.4. Little-Endian Interpretation of Words as Bytes
All mathematical operations are on 64-bit words in BLAKE2b and on
32-bit words in BLAKE2s.
We may also perform operations on vectors of words. Vector indexing
is zero based; the first element of an n-element vector "v" is v[0]
and the last one is v[n - 1]. All elements are denoted by v[0..n-1].
Byte (octet) streams are interpreted as words in little-endian order,
with the least-significant byte first. Consider this sequence of
eight hexadecimal bytes:
x[0..7] = 0x01 0x23 0x45 0x67 0x89 0xAB 0xCD 0xEF
When interpreted as a 32-bit word from the beginning memory address,
x[0..3] has a numerical value of 0x67452301 or 1732584193.
When interpreted as a 64-bit word, bytes x[0..7] have a numerical
value of 0xEFCDAB8967452301 or 17279655951921914625.
2.5. Parameter Block
We specify the parameter block words p[0..7] as follows:
byte offset: 3 2 1 0 (otherwise zero)
p[0] = 0x0101kknn p[1..7] = 0
Here the "nn" byte specifies the hash size in bytes. The second
(little-endian) byte of the parameter block, "kk", specifies the key
size in bytes. Set kk = 00 for unkeyed hashing. Bytes 2 and 3 are
set as 01. All other bytes in the parameter block are set as zero.
Note: [BLAKE2] defines additional variants of BLAKE2 with features
such as salting, personalized hashes, and tree hashing. These
OPTIONAL features use fields in the parameter block that are not
defined in this document.
2.6. Initialization Vector
We define the Initialization Vector constant IV mathematically as:
IV[i] = floor(2**w * frac(sqrt(prime(i+1)))), where prime(i)
is the i:th prime number ( 2, 3, 5, 7, 11, 13, 17, 19 )
and sqrt(x) is the square root of x.
The numerical values of IV can also be found in implementations in
Appendices C and D for BLAKE2b and BLAKE2s, respectively.
Saarinen & Aumasson Informational [Page 5]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
Note: BLAKE2b IV is the same as SHA-512 IV, and BLAKE2s IV is the
same as SHA-256 IV; see [RFC6234].
2.7. Message Schedule SIGMA
Message word schedule permutations for each round of both BLAKE2b and
BLAKE2s are defined by SIGMA. For BLAKE2b, the two extra
permutations for rounds 10 and 11 are SIGMA[10..11] = SIGMA[0..1].
Round | 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
----------+-------------------------------------------------+
SIGMA[0] | 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 |
SIGMA[1] | 14 10 4 8 9 15 13 6 1 12 0 2 11 7 5 3 |
SIGMA[2] | 11 8 12 0 5 2 15 13 10 14 3 6 7 1 9 4 |
SIGMA[3] | 7 9 3 1 13 12 11 14 2 6 5 10 4 0 15 8 |
SIGMA[4] | 9 0 5 7 2 4 10 15 14 1 11 12 6 8 3 13 |
SIGMA[5] | 2 12 6 10 0 11 8 3 4 13 7 5 15 14 1 9 |
SIGMA[6] | 12 5 1 15 14 13 4 10 0 7 6 3 9 2 8 11 |
SIGMA[7] | 13 11 7 14 12 1 3 9 5 0 15 4 8 6 2 10 |
SIGMA[8] | 6 15 14 9 11 3 0 8 12 2 13 7 1 4 10 5 |
SIGMA[9] | 10 2 8 4 7 6 1 5 15 11 9 14 3 12 13 0 |
----------+-------------------------------------------------+
3. BLAKE2 Processing
3.1. Mixing Function G
The G primitive function mixes two input words, "x" and "y", into
four words indexed by "a", "b", "c", and "d" in the working vector
v[0..15]. The full modified vector is returned. The rotation
constants (R1, R2, R3, R4) are given in Section 2.1.
FUNCTION G( v[0..15], a, b, c, d, x, y )
|
| v[a] := (v[a] + v[b] + x) mod 2**w
| v[d] := (v[d] ^ v[a]) >>> R1
| v[c] := (v[c] + v[d]) mod 2**w
| v[b] := (v[b] ^ v[c]) >>> R2
| v[a] := (v[a] + v[b] + y) mod 2**w
| v[d] := (v[d] ^ v[a]) >>> R3
| v[c] := (v[c] + v[d]) mod 2**w
| v[b] := (v[b] ^ v[c]) >>> R4
|
| RETURN v[0..15]
|
END FUNCTION.
Saarinen & Aumasson Informational [Page 6]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
3.2. Compression Function F
Compression function F takes as an argument the state vector "h",
message block vector "m" (last block is padded with zeros to full
block size, if required), 2w-bit offset counter "t", and final block
indicator flag "f". Local vector v[0..15] is used in processing. F
returns a new state vector. The number of rounds, "r", is 12 for
BLAKE2b and 10 for BLAKE2s. Rounds are numbered from 0 to r - 1.
FUNCTION F( h[0..7], m[0..15], t, f )
|
| // Initialize local work vector v[0..15]
| v[0..7] := h[0..7] // First half from state.
| v[8..15] := IV[0..7] // Second half from IV.
|
| v[12] := v[12] ^ (t mod 2**w) // Low word of the offset.
| v[13] := v[13] ^ (t >> w) // High word.
|
| IF f = TRUE THEN // last block flag?
| | v[14] := v[14] ^ 0xFF..FF // Invert all bits.
| END IF.
|
| // Cryptographic mixing
| FOR i = 0 TO r - 1 DO // Ten or twelve rounds.
| |
| | // Message word selection permutation for this round.
| | s[0..15] := SIGMA[i mod 10][0..15]
| |
| | v := G( v, 0, 4, 8, 12, m[s[ 0]], m[s[ 1]] )
| | v := G( v, 1, 5, 9, 13, m[s[ 2]], m[s[ 3]] )
| | v := G( v, 2, 6, 10, 14, m[s[ 4]], m[s[ 5]] )
| | v := G( v, 3, 7, 11, 15, m[s[ 6]], m[s[ 7]] )
| |
| | v := G( v, 0, 5, 10, 15, m[s[ 8]], m[s[ 9]] )
| | v := G( v, 1, 6, 11, 12, m[s[10]], m[s[11]] )
| | v := G( v, 2, 7, 8, 13, m[s[12]], m[s[13]] )
| | v := G( v, 3, 4, 9, 14, m[s[14]], m[s[15]] )
| |
| END FOR
|
| FOR i = 0 TO 7 DO // XOR the two halves.
| | h[i] := h[i] ^ v[i] ^ v[i + 8]
| END FOR.
|
| RETURN h[0..7] // New state.
|
END FUNCTION.
Saarinen & Aumasson Informational [Page 7]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
3.3. Padding Data and Computing a BLAKE2 Digest
We refer the reader to Appendices C and D for reference C language
implementations of BLAKE2b and BLAKE2s, respectively.
Key and data input are split and padded into "dd" message blocks
d[0..dd-1], each consisting of 16 words (or "bb" bytes).
If a secret key is used (kk > 0), it is padded with zero bytes and
set as d[0]. Otherwise, d[0] is the first data block. The final
data block d[dd-1] is also padded with zero to "bb" bytes (16 words).
The number of blocks is therefore dd = ceil(kk / bb) + ceil(ll / bb).
However, in the special case of an unkeyed empty message (kk = 0 and
ll = 0), we still set dd = 1 and d[0] consists of all zeros.
The following procedure processes the padded data blocks into an
"nn"-byte final hash value. See Section 2 for a description of
various variables and constants used.
FUNCTION BLAKE2( d[0..dd-1], ll, kk, nn )
|
| h[0..7] := IV[0..7] // Initialization Vector.
|
| // Parameter block p[0]
| h[0] := h[0] ^ 0x01010000 ^ (kk << 8) ^ nn
|
| // Process padded key and data blocks
| IF dd > 1 THEN
| | FOR i = 0 TO dd - 2 DO
| | | h := F( h, d[i], (i + 1) * bb, FALSE )
| | END FOR.
| END IF.
|
| // Final block.
| IF kk = 0 THEN
| | h := F( h, d[dd - 1], ll, TRUE )
| ELSE
| | h := F( h, d[dd - 1], ll + bb, TRUE )
| END IF.
|
| RETURN first "nn" bytes from little-endian word array h[].
|
END FUNCTION.
Saarinen & Aumasson Informational [Page 8]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
4. Standard Parameter Sets and Algorithm Identifiers
An implementation of BLAKE2b and/or BLAKE2s MAY support the following
digest size parameters for interoperability (e.g., digital
signatures), as long as a sufficient level of security is attained by
the parameter selections. These parameters and identifiers are
intended to be suitable as drop-in replacements to MD5 and
corresponding SHA algorithms.
Developers adapting BLAKE2 to ASN.1-based message formats SHOULD use
the OID tree at x = 1.3.6.1.4.1.1722.12.2. The same OID can be used
for both keyed and unkeyed hashing since in the latter case the key
simply has zero length.
Algorithm | Target | Collision | Hash | Hash ASN.1 |
Identifier | Arch | Security | nn | OID Suffix |
---------------+--------+-----------+------+------------+
id-blake2b160 | 64-bit | 2**80 | 20 | x.1.5 |
id-blake2b256 | 64-bit | 2**128 | 32 | x.1.8 |
id-blake2b384 | 64-bit | 2**192 | 48 | x.1.12 |
id-blake2b512 | 64-bit | 2**256 | 64 | x.1.16 |
---------------+--------+-----------+------+------------+
id-blake2s128 | 32-bit | 2**64 | 16 | x.2.4 |
id-blake2s160 | 32-bit | 2**80 | 20 | x.2.5 |
id-blake2s224 | 32-bit | 2**112 | 28 | x.2.7 |
id-blake2s256 | 32-bit | 2**128 | 32 | x.2.8 |
---------------+--------+-----------+------+------------+
Saarinen & Aumasson Informational [Page 9]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
hashAlgs OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6) internet(1)
private(4) enterprise(1) kudelski(1722) cryptography(12) 2
}
macAlgs OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6) internet(1)
private(4) enterprise(1) kudelski(1722) cryptography(12) 3
}
-- the two BLAKE2 variants --
blake2b OBJECT IDENTIFIER ::= { hashAlgs 1 }
blake2s OBJECT IDENTIFIER ::= { hashAlgs 2 }
-- BLAKE2b Identifiers --
id-blake2b160 OBJECT IDENTIFIER ::= { blake2b 5 }
id-blake2b256 OBJECT IDENTIFIER ::= { blake2b 8 }
id-blake2b384 OBJECT IDENTIFIER ::= { blake2b 12 }
id-blake2b512 OBJECT IDENTIFIER ::= { blake2b 16 }
-- BLAKE2s Identifiers --
id-blake2s128 OBJECT IDENTIFIER ::= { blake2s 4 }
id-blake2s160 OBJECT IDENTIFIER ::= { blake2s 5 }
id-blake2s224 OBJECT IDENTIFIER ::= { blake2s 7 }
id-blake2s256 OBJECT IDENTIFIER ::= { blake2s 8 }
5. Security Considerations
This document is intended to provide convenient open-source access by
the Internet community to the BLAKE2 cryptographic hash algorithm.
We wish to make no independent assertion to its security in this
document. We refer the reader to [BLAKE] and [BLAKE2] for detailed
cryptanalytic rationale behind its design.
In order to avoid bloat, the reference implementations in Appendices
C and D may not erase all sensitive data (such as secret keys)
immediately from process memory after use. Such cleanup can be added
if needed.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
Saarinen & Aumasson Informational [Page 10]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
6.2. Informative References
[BLAKE] Aumasson, J-P., Meier, W., Phan, R., and L. Henzen, "The
Hash Function BLAKE", January 2015,
<https://131002.net/blake/book>.
[BLAKE2] Aumasson, J-P., Neves, S., Wilcox-O'Hearn, Z., and C.
Winnerlein, "BLAKE2: simpler, smaller, fast as MD5",
January 2013, <https://blake2.net/blake2.pdf>.
[FIPS140-2IG]
NIST, "Implementation Guidance for FIPS PUB 140-2 and the
Cryptographic Module Validation Program", September 2015,
<http://csrc.nist.gov/groups/STM/cmvp/documents/fips140-2/
FIPS1402IG.pdf/>.
[RFC6151] Turner, S. and L. Chen, "Updated Security Considerations
for the MD5 Message-Digest and the HMAC-MD5 Algorithms",
RFC 6151, DOI 10.17487/RFC6151, March 2011,
<http://www.rfc-editor.org/info/rfc6151>.
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<http://www.rfc-editor.org/info/rfc6234>.
Appendix A. Example of BLAKE2b Computation
We compute the unkeyed hash of three ASCII bytes "abc" with
BLAKE2b-512 and show internal values during computation.
m[16] = 0000000000636261 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000
0000000000000000 0000000000000000 0000000000000000
0000000000000000
(i= 0) v[16] = 6A09E667F2BDC948 BB67AE8584CAA73B 3C6EF372FE94F82B
A54FF53A5F1D36F1 510E527FADE682D1 9B05688C2B3E6C1F
1F83D9ABFB41BD6B 5BE0CD19137E2179 6A09E667F3BCC908
BB67AE8584CAA73B 3C6EF372FE94F82B A54FF53A5F1D36F1
510E527FADE682D2 9B05688C2B3E6C1F E07C265404BE4294
5BE0CD19137E2179
(i= 1) v[16] = 86B7C1568029BB79 C12CBCC809FF59F3 C6A5214CC0EACA8E
0C87CD524C14CC5D 44EE6039BD86A9F7 A447C850AA694A7E
DE080F1BB1C0F84B 595CB8A9A1ACA66C BEC3AE837EAC4887
Saarinen & Aumasson Informational [Page 11]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
6267FC79DF9D6AD1 FA87B01273FA6DBE 521A715C63E08D8A
E02D0975B8D37A83 1C7B754F08B7D193 8F885A76B6E578FE
2318A24E2140FC64
(i= 2) v[16] = 53281E83806010F2 3594B403F81B4393 8CD63C7462DE0DFF
85F693F3DA53F974 BAABDBB2F386D9AE CA5425AEC65A10A8
C6A22E2FF0F7AA48 C6A56A51CB89C595 224E6A3369224F96
500E125E58A92923 E9E4AD0D0E1A0D48 85DF9DC143C59A74
92A3AAAA6D952B7F C5FDF71090FAE853 2A8A40F15A462DD0
572D17EFFDD37358
(i= 3) v[16] = 60ED96AA7AD41725 E46A743C71800B9D 1A04B543A01F156B
A2F8716E775C4877 DA0A61BCDE4267EA B1DD230754D7BDEE
25A1422779E06D14 E6823AE4C3FF58A5 A1677E19F37FD5DA
22BDCE6976B08C51 F1DE8696BEC11BF1 A0EBD586A4A1D2C8
C804EBAB11C99FA9 8E0CEC959C715793 7C45557FAE0D4D89
716343F52FDD265E
(i= 4) v[16] = BB2A77D3A8382351 45EB47971F23B103 98BE297F6E45C684
A36077DEE3370B89 8A03C4CB7E97590A 24192E49EBF54EA0
4F82C9401CB32D7A 8CCD013726420DC4 A9C9A8F17B1FC614
55908187977514A0 5B44273E66B19D27 B6D5C9FCA2579327
086092CFB858437E 5C4BE2156DBEECF9 2EFEDE99ED4EFF16
3E7B5F234CD1F804
(i= 5) v[16] = C79C15B3D423B099 2DA2224E8DA97556 77D2B26DF1C45C55
8934EB09A3456052 0F6D9EEED157DA2A 6FE66467AF88C0A9
4EB0B76284C7AAFB 299C8E725D954697 B2240B59E6D567D3
2643C2370E49EBFD 79E02EEF20CDB1AE 64B3EED7BB602F39
B97D2D439E4DF63D C718E755294C9111 1F0893F2772BB373
1205EA4A7859807D
(i= 6) v[16] = E58F97D6385BAEE4 7640AA9764DA137A DEB4C7C23EFE287E
70F6F41C8783C9F6 7127CD48C76A7708 9E472AF0BE3DB3F6
0F244C62DDF71788 219828AA83880842 41CCA9073C8C4D0D
5C7912BC10DF3B4B A2C3ABBD37510EE2 CB5668CC2A9F7859
8733794F07AC1500 C67A6BE42335AA6F ACB22B28681E4C82
DB2161604CBC9828
(i= 7) v[16] = 6E2D286EEADEDC81 BCF02C0787E86358 57D56A56DD015EDF
55D899D40A5D0D0A 819415B56220C459 B63C479A6A769F02
258E55E0EC1F362A 3A3B4EC60E19DFDC 04D769B3FCB048DB
B78A9A33E9BFF4DD 5777272AE1E930C0 5A387849E578DBF6
92AAC307CF2C0AFC 30AACCC4F06DAFAA 483893CC094F8863
E03C6CC89C26BF92
(i= 8) v[16] = FFC83ECE76024D01 1BE7BFFB8C5CC5F9 A35A18CBAC4C65B7
B7C2C7E6D88C285F 81937DA314A50838 E1179523A2541963
Saarinen & Aumasson Informational [Page 12]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
3A1FAD7106232B8F 1C7EDE92AB8B9C46 A3C2D35E4F685C10
A53D3F73AA619624 30BBCC0285A22F65 BCEFBB6A81539E5D
3841DEF6F4C9848A 98662C85FBA726D4 7762439BD5A851BD
B0B9F0D443D1A889
(i= 9) v[16] = 753A70A1E8FAEADD 6B0D43CA2C25D629 F8343BA8B94F8C0B
BC7D062B0DB5CF35 58540EE1B1AEBC47 63C5B9B80D294CB9
490870ECAD27DEBD B2A90DDF667287FE 316CC9EBEEFAD8FC
4A466BCD021526A4 5DA7F7638CEC5669 D9C8826727D306FC
88ED6C4F3BD7A537 19AE688DDF67F026 4D8707AAB40F7E6D
FD3F572687FEA4F1
(i=10) v[16] = E630C747CCD59C4F BC713D41127571CA 46DB183025025078
6727E81260610140 2D04185EAC2A8CBA 5F311B88904056EC
40BD313009201AAB 0099D4F82A2A1EAB 6DD4FBC1DE60165D
B3B0B51DE3C86270 900AEE2F233B08E5 A07199D87AD058D8
2C6B25593D717852 37E8CA471BEAA5F8 2CFC1BAC10EF4457
01369EC18746E775
(i=11) v[16] = E801F73B9768C760 35C6D22320BE511D 306F27584F65495E
B51776ADF569A77B F4F1BE86690B3C34 3CC88735D1475E4B
5DAC67921FF76949 1CDB9D31AD70CC4E 35BA354A9C7DF448
4929CBE45679D73E 733D1A17248F39DB 92D57B736F5F170A
61B5C0A41D491399 B5C333457E12844A BD696BE010D0D889
02231E1A917FE0BD
(i=12) v[16] = 12EF8A641EC4F6D6 BCED5DE977C9FAF5 733CA476C5148639
97DF596B0610F6FC F42C16519AD5AFA7 AA5AC1888E10467E
217D930AA51787F3 906A6FF19E573942 75AB709BD3DCBF24
EE7CE1F345947AA4 F8960D6C2FAF5F5E E332538A36B6D246
885BEF040EF6AA0B A4939A417BFB78A3 646CBB7AF6DCE980
E813A23C60AF3B82
h[8] = 0D4D1C983FA580BA E9F6129FB697276A B7C45A68142F214C
D1A2FFDB6FBB124B 2D79AB2A39C5877D 95CC3345DED552C2
5A92F1DBA88AD318 239900D4ED8623B9
BLAKE2b-512("abc") = BA 80 A5 3F 98 1C 4D 0D 6A 27 97 B6 9F 12 F6 E9
4C 21 2F 14 68 5A C4 B7 4B 12 BB 6F DB FF A2 D1
7D 87 C5 39 2A AB 79 2D C2 52 D5 DE 45 33 CC 95
18 D3 8A A8 DB F1 92 5A B9 23 86 ED D4 00 99 23
Appendix B. Example of BLAKE2s Computation
We compute the unkeyed hash of three ASCII bytes "abc" with
BLAKE2s-256 and show internal values during computation.
m[16] = 00636261 00000000 00000000 00000000 00000000 00000000
Saarinen & Aumasson Informational [Page 13]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000
(i=0) v[16] = 6B08E647 BB67AE85 3C6EF372 A54FF53A 510E527F 9B05688C
1F83D9AB 5BE0CD19 6A09E667 BB67AE85 3C6EF372 A54FF53A
510E527C 9B05688C E07C2654 5BE0CD19
(i=1) v[16] = 16A3242E D7B5E238 CE8CE24B 927AEDE1 A7B430D9 93A4A14E
A44E7C31 41D4759B 95BF33D3 9A99C181 608A3A6B B666383E
7A8DD50F BE378ED7 353D1EE6 3BB44C6B
(i=2) v[16] = 3AE30FE3 0982A96B E88185B4 3E339B16 F24338CD 0E66D326
E005ED0C D591A277 180B1F3A FCF43914 30DB62D6 4847831C
7F00C58E FB847886 C544E836 524AB0E2
(i=3) v[16] = 7A3BE783 997546C1 D45246DF EDB5F821 7F98A742 10E864E2
D4AB70D0 C63CB1AB 6038DA9E 414594B0 F2C218B5 8DA0DCB7
D7CD7AF5 AB4909DF 85031A52 C4EDFC98
(i=4) v[16] = 2A8B8CB7 1ACA82B2 14045D7F CC7258ED 383CF67C E090E7F9
3025D276 57D04DE4 994BACF0 F0982759 F17EE300 D48FC2D5
DC854C10 523898A9 C03A0F89 47D6CD88
(i=5) v[16] = C4AA2DDB 111343A3 D54A700A 574A00A9 857D5A48 B1E11989
6F5C52DF DD2C53A3 678E5F8E 9718D4E9 622CB684 92976076
0E41A517 359DC2BE 87A87DDD 643F9CEC
(i=6) v[16] = 3453921C D7595EE1 592E776D 3ED6A974 4D997CB3 DE9212C3
35ADF5C9 9916FD65 96562E89 4EAD0792 EBFC2712 2385F5B2
F34600FB D7BC20FB EB452A7B ECE1AA40
(i=7) v[16] = BE851B2D A85F6358 81E6FC3B 0BB28000 FA55A33A 87BE1FAD
4119370F 1E2261AA A1318FD3 F4329816 071783C2 6E536A8D
9A81A601 E7EC80F1 ACC09948 F849A584
(i=8) v[16] = 07E5B85A 069CC164 F9DE3141 A56F4680 9E440AD2 9AB659EA
3C84B971 21DBD9CF 46699F8C 765257EC AF1D998C 75E4C3B6
523878DC 30715015 397FEE81 4F1FA799
(i=9) v[16] = 435148C4 A5AA2D11 4B354173 D543BC9E BDA2591C BF1D2569
4FCB3120 707ADA48 565B3FDE 32C9C916 EAF4A1AB B1018F28
8078D978 68ADE4B5 9778FDA3 2863B92E
(i=10) v[16] = D9C994AA CFEC3AA6 700D0AB2 2C38670E AF6A1F66 1D023EF3
1D9EC27D 945357A5 3E9FFEBD 969FE811 EF485E21 A632797A
DEEF082E AF3D80E1 4E86829B 4DEAFD3A
h[8] = 8C5E8C50 E2147C32 A32BA7E1 2F45EB4E 208B4537 293AD69E
Saarinen & Aumasson Informational [Page 14]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
4C9B994D 82596786
BLAKE2s-256("abc") = 50 8C 5E 8C 32 7C 14 E2 E1 A7 2B A3 4E EB 45 2F
37 45 8B 20 9E D6 3A 29 4D 99 9B 4C 86 67 59 82
Appendix C. BLAKE2b Implementation C Source
C.1. blake2b.h
Saarinen & Aumasson Informational [Page 15]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
<CODE BEGINS>
// blake2b.h
// BLAKE2b Hashing Context and API Prototypes
#ifndef BLAKE2B_H
#define BLAKE2B_H
#include <stdint.h>
#include <stddef.h>
// state context
typedef struct {
uint8_t b[128]; // input buffer
uint64_t h[8]; // chained state
uint64_t t[2]; // total number of bytes
size_t c; // pointer for b[]
size_t outlen; // digest size
} blake2b_ctx;
// Initialize the hashing context "ctx" with optional key "key".
// 1 <= outlen <= 64 gives the digest size in bytes.
// Secret key (also <= 64 bytes) is optional (keylen = 0).
int blake2b_init(blake2b_ctx *ctx, size_t outlen,
const void *key, size_t keylen); // secret key
// Add "inlen" bytes from "in" into the hash.
void blake2b_update(blake2b_ctx *ctx, // context
const void *in, size_t inlen); // data to be hashed
// Generate the message digest (size given in init).
// Result placed in "out".
void blake2b_final(blake2b_ctx *ctx, void *out);
// All-in-one convenience function.
int blake2b(void *out, size_t outlen, // return buffer for digest
const void *key, size_t keylen, // optional secret key
const void *in, size_t inlen); // data to be hashed
#endif
<CODE ENDS>
C.2. blake2b.c
<CODE BEGINS>
// blake2b.c
// A simple BLAKE2b Reference Implementation.
#include "blake2b.h"
Saarinen & Aumasson Informational [Page 16]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
// Cyclic right rotation.
#ifndef ROTR64
#define ROTR64(x, y) (((x) >> (y)) ^ ((x) << (64 - (y))))
#endif
// Little-endian byte access.
#define B2B_GET64(p) \
(((uint64_t) ((uint8_t *) (p))[0]) ^ \
(((uint64_t) ((uint8_t *) (p))[1]) << 8) ^ \
(((uint64_t) ((uint8_t *) (p))[2]) << 16) ^ \
(((uint64_t) ((uint8_t *) (p))[3]) << 24) ^ \
(((uint64_t) ((uint8_t *) (p))[4]) << 32) ^ \
(((uint64_t) ((uint8_t *) (p))[5]) << 40) ^ \
(((uint64_t) ((uint8_t *) (p))[6]) << 48) ^ \
(((uint64_t) ((uint8_t *) (p))[7]) << 56))
// G Mixing function.
#define B2B_G(a, b, c, d, x, y) { \
v[a] = v[a] + v[b] + x; \
v[d] = ROTR64(v[d] ^ v[a], 32); \
v[c] = v[c] + v[d]; \
v[b] = ROTR64(v[b] ^ v[c], 24); \
v[a] = v[a] + v[b] + y; \
v[d] = ROTR64(v[d] ^ v[a], 16); \
v[c] = v[c] + v[d]; \
v[b] = ROTR64(v[b] ^ v[c], 63); }
// Initialization Vector.
static const uint64_t blake2b_iv[8] = {
0x6A09E667F3BCC908, 0xBB67AE8584CAA73B,
0x3C6EF372FE94F82B, 0xA54FF53A5F1D36F1,
0x510E527FADE682D1, 0x9B05688C2B3E6C1F,
0x1F83D9ABFB41BD6B, 0x5BE0CD19137E2179
};
// Compression function. "last" flag indicates last block.
static void blake2b_compress(blake2b_ctx *ctx, int last)
{
const uint8_t sigma[12][16] = {
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
{ 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 },
{ 11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4 },
{ 7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8 },
Saarinen & Aumasson Informational [Page 17]
RFC 7693 BLAKE2 Crypto Hash and MAC November 2015
{ 9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13 },
{ 2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9 },
{ 12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11 },
{ 13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10 },
{ 6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5 },
{ 10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0 },
{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
{ 14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3 }
};
int i;
uint64_t v[16], m[16];
for (i = 0; i < 8; i++) { // init work variables
v[i] = ctx->h[i];
v[i + 8] = blake2b_iv[i];
}
v[12] ^= ctx->t[0]; // low 64 bits of offset
v[13] ^= ctx->t[1]; // high 64 bits
if (last) // last block flag set ?
v[14] = ~v[14];
for (i = 0; i < 16; i++) // get little-endian words
m[i] = B2B_GET64(&ctx->b[8 * i]);
for (i = 0; i < 12; i++) { // twelve rounds
B2B_G( 0, 4, 8, 12, m[sigma[i][ 0]], m[sigma[i][ 1]]);
B2B_G( 1, 5, 9, 13, m[sigma[i][ 2]], m[sigma[i][ 3]]);
B2B_G( 2, 6, 10, 14, m[sigma[i][ 4]], m[sigma[i][ 5]]);
B2B_G( 3, 7, 11, 15, m[sigma[i][ 6]], m[sigma[i][ 7]]);
B2B_G( 0, 5, 10, 15, m[sigma[i][ 8]], m[sigma[i][ 9]]);
B2B_G( 1, 6, 11, 12, m[sigma[i][10]], m[sigma[i][11]]);
B2B_G( 2, 7, 8, 13, m[sigma[i][12]], m[sigma[i][13]]);
B2B_G( 3, 4, 9, 14, m[sigma[i][14]], m[sigma[i][15]]);
}
for( i = 0; i < 8; ++i )
ctx->h[i] ^= v[i] ^ v[i + 8];
}
// Initialize the hashing context "ctx" with optional key "key".
// 1 <= outlen <= 64 gives the digest size in bytes.