| Internet Engineering Task Force | M-J. Saarinen, Ed. |
| Internet-Draft | Independent Consultant |
| Intended status: Informational | J-P. Aumasson |
| Expires: August 5, 2015 | Kudelski Security |
| February 1, 2015 |
The BLAKE2 Cryptographic Hash and MAC
draft-saarinen-blake2-00
This document describes the cryptographic hash function BLAKE2, making 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).
This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 5, 2015.
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. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
The [BLAKE2] cryptographic hash function was designed by Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn, and Christian Winnerlein.
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.
BLAKE2 provides an efficient alternative to US Secure Hash Algorithms SHA and HMAC-SHA [RFC6234]. Note that BLAKE2 algorithms do not require a special "HMAC" construction for keyed message authentication as they have a built-in keying mechanism.
BLAKE2 comes in two basic flavors:
Both BLAKE2b and BLAKE2s are believed to be highly secure and have good performance on any platform, software or hardware.
A reference implementation in C programming language for BLAKE2b can be found in Appendix A and for BLAKE2s in Appendix B of this document. These implementations SHOULD be validated with the Test Module contained in Appendix C.
Due to space constraints, this document does not contain a full set of test vectors for BLAKE2. We refer to [BLAKE2] for up to date information about compliance testing and integrating BLAKE2 into various applications.
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this document, are to be interpreted as described in [RFC2119].
The following table summarizes various parameters and their acceptable ranges for the two variants. These constants and variables are used in the algorithm descriptions in Section 3.
| 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) | --------------+------------------+------------------+
For real-valued x we define:
Operator notation in pseudocode:
All mathematical operations are on 64-bit words in BLAKE2b and on 32-bit words on BLAKE2b. 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 is 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 numerical value 0x67452301 or 1732584193.
When interpreted as a 64-bit word, bytes x[0..7] have numerical value 0xEFCDAB8967452301 or 17279655951921914625.
We specify the parameter block words p[0..7] as follows:
byte offset: 3 2 1 0 p[0] = 0x0101kknn p[1..7] = 0 (otherwise empty)
Here the "nn" byte specifies the hash size in bytes. The second (little-endian) byte of parameter block, "kk", specifies key size in bytes. Set kk = 00 for 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 which are not defined in this document.
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.
We define the Initialization Vector constant IV mathematically as: [RFC6234]. The numerical values of IV can be also found in implementations in Appendix A and Appendix B for BLAkE2b and BLAKE2s, respectively.
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 | ----------+-------------------------------------------------+
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.
Compression function F takes as an argument the state vector "h", zero-padded message block vector "m", 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 | | h[i] := v[i] ^ v[i + 8] // XOR the two halves. | END FOR. | | RETURN h[0..7] // New state. | END FUNCTION.
We refer the reader to Appendix A and Appendix B for reference C language implementations of BLAkE2b and BLAKE2s, respectively.
Key and data input is 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).
Number of blocks is therefore dd = ceil(kk / bb) + ceil(ll / bb). However in special case of unkeyed empty message (kk = 0 and ll = 0), we still set dd = 1 and d[0] consists of all zeros.
The following procedure for processes the padded data blocks into an "nn"-byte final hash value. See Section 2 for 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 := COMPRESS( h, d[i], (i + 1) * bb, FALSE )
| | END FOR.
| END IF.
|
| // Final block.
| IF kk = 0 THEN
| | h := COMPRESS( h, d[dd - 1], ll, TRUE )
| ELSE
| | h := COMPRESS( h, d[dd - 1], ll + bb, TRUE )
| END IF.
|
| RETURN first "nn" bytes from little-endian word array h[].
|
END FUNCTION.
An implementation of BLAKE2b and / or BLAKE2s SHOULD support the following digest size parameters for interoperability (e.g. digital signatures), as long as sufficient level of security is attained by the parameter selections. These parameters and identifiers are intended as plug-in replacements to corresponding SHA algorithms.
Keyed hashing is OPTIONAL. Implementation of BLAKE2s is OPTIONAL.
For unkeyed hashing, 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.
Algorithm | Target | Collision | Hash | Hash ASN.1 | Identifier | Arch | Security | nn | OID Suffix | ---------------+--------+-----------+------+------------+ id-blake2b160 | 64-bit | 2**80 | 20 | x.1.20 | id-blake2b256 | 64-bit | 2**128 | 32 | x.1.32 | id-blake2b384 | 64-bit | 2**192 | 48 | x.1.48 | id-blake2b512 | 64-bit | 2**256 | 64 | x.1.64 | ---------------+--------+-----------+------+------------+ id-blake2s128 | 32-bit | 2**64 | 16 | x.2.16 | id-blake2s160 | 32-bit | 2**80 | 20 | x.2.20 | id-blake2s224 | 32-bit | 2**112 | 28 | x.2.28 | id-blake2s256 | 32-bit | 2**128 | 32 | x.2.32 | ---------------+--------+-----------+------+------------+
hashAlgs OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6) internet(1)
private(4) enterprise(1) kudelski(1722) cryptography(12) 2
}
-- the two BLAKE2 variants --
blake2b OBJECT IDENTIFIER ::= { hashAlgs 1 }
blake2s OBJECT IDENTIFIER ::= { hashAlgs 2 }
-- BLAKE2b Identifiers --
id-blake2b160 OBJECT IDENTIFIER ::= { blake2b 20 }
id-blake2b256 OBJECT IDENTIFIER ::= { blake2b 32 }
id-blake2b384 OBJECT IDENTIFIER ::= { blake2b 48 }
id-blake2b512 OBJECT IDENTIFIER ::= { blake2b 64 }
-- BLAKE2s Identifiers --
id-blake2s128 OBJECT IDENTIFIER ::= { blake2s 16 }
id-blake2s160 OBJECT IDENTIFIER ::= { blake2s 20 }
id-blake2s224 OBJECT IDENTIFIER ::= { blake2s 28 }
id-blake2s256 OBJECT IDENTIFIER ::= { blake2s 32 }
The editor wishes to thank the [BLAKE2] team for their encouragement: Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hearn, and Christian Winnerlein. We have borrowed passages from [BLAKE] and [BLAKE2] with permission.
BLAKE2 is based on the SHA-3 proposal [BLAKE], designed by Jean-Philippe Aumasson, Luca Henzen, Willi Meier, and Raphael C.-W. Phan. BLAKE2, like BLAKE, relies on a core algorithm borrowed from the ChaCha stream cipher, designed by Daniel J. Bernstein.
This memo includes no request to IANA.
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 Appendix A and Appendix B may not erase all sensitive data (such as secret keys) immediately from process memory after use. Such cleanups can be added if needed.
| [BLAKE2] | Aumasson, J-P., Neves, S., Wilcox-O'Hearn, Z. and C. Winnerlein, "BLAKE2: simpler, smaller, fast as MD5", January 2013. |
| [BLAKE] | Aumasson, J-P., Meier, W., Phan, R. and L. Henzen, "The Hash Function BLAKE", February 2015. |
| [FIPS140-2IG] | NIST, US., "Implementation Guidance for FIPS PUB 140-2 and the Cryptographic Module Validation Program", January 2015. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, BCP 14, March 1997. |
| [RFC6234] | Eastlake, D. and T. Hansen, "US Secure Hash Algorithms (SHA and SHA-based HMAC and HKDF)", RFC 6234, May 2011. |
// 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
// blake2b.c
// A simple BLAKE2b Reference Implementation
#include "blake2b.h"
// 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 },
{ 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 state. key is optional
int blake2b_init(blake2b_ctx *ctx, size_t outlen,
const void *key, size_t keylen) // (keylen=0: no key)
{
size_t i;
if (outlen == 0 || outlen > 64 || keylen > 64)
return -1; // illegal parameters
for (i = 0; i < 8; i++) // state, "param block"
ctx->h[i] = blake2b_iv[i];
ctx->h[0] ^= 0x01010000 ^ (keylen << 8) ^ outlen;
ctx->t[0] = 0; // input count low word
ctx->t[1] = 0; // input count high word
ctx->c = 0; // pointer within buffer
ctx->outlen = outlen;
for (i = keylen; i < 128; i++) // zero input block
ctx->b[i] = 0;
if (keylen > 0) {
blake2b_update(ctx, key, keylen);
ctx->c = 128; // at the end
}
return 0;
}
// update with new data
void blake2b_update(blake2b_ctx *ctx,
const void *in, size_t inlen) // data bytes
{
size_t i;
for (i = 0; i < inlen; i++) {
if (ctx->c == 128) { // buffer full ?
ctx->t[0] += ctx->c; // add counters
if (ctx->t[0] < ctx->c) // carry overflow ?
ctx->t[1]++; // high word
blake2b_compress(ctx, 0); // compress (not last)
ctx->c = 0; // counter to zero
}
ctx->b[ctx->c++] = ((const uint8_t *) in)[i];
}
}
// finalize
void blake2b_final(blake2b_ctx *ctx, void *out)
{
size_t i;
ctx->t[0] += ctx->c; // mark last block offset
if (ctx->t[0] < ctx->c) // carry overflow
ctx->t[1]++; // high word
while (ctx->c < 128) // fill up with zeros
ctx->b[ctx->c++] = 0;
blake2b_compress(ctx, 1); // final block flag = 1
// little endian convert and store
for (i = 0; i < ctx->outlen; i++) {
((uint8_t *) out)[i] =
(ctx->h[i >> 3] >> (8 * (i & 7))) & 0xFF;
}
}
// convenience function for all-in-one computation
int blake2b(void *out, size_t outlen,
const void *key, size_t keylen,
const void *in, size_t inlen)
{
blake2b_ctx ctx;
if (blake2b_init(&ctx, outlen, key, keylen))
return -1;
blake2b_update(&ctx, in, inlen);
blake2b_final(&ctx, out);
return 0;
}
// blake2s.h
// BLAKE2s Hashing Context and API Prototypes
#ifndef BLAKE2S_H
#define BLAKE2S_H
#include <stdint.h>
#include <stddef.h>
// state context
typedef struct {
uint8_t b[64]; // input buffer
uint32_t h[8]; // chained state
uint32_t t[2]; // total number of bytes
size_t c; // pointer for b[]
size_t outlen; // digest size
} blake2s_ctx;
// Initialize the hashing context "ctx" with optional key "key".
// 1 <= outlen <= 32 gives the digest size in bytes.
// Secret key (also <= 32 bytes) is optional (keylen = 0).
int blake2s_init(blake2s_ctx *ctx, size_t outlen,
const void *key, size_t keylen); // secret key
// Add "inlen" bytes from "in" into the hash.
void blake2s_update(blake2s_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 blake2s_final(blake2s_ctx *ctx, void *out);
// All-in-one convenience function.
int blake2s(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
// blake2s.c
// A simple BLAKE2 Reference Implementation
#include "blake2s.h"
// cyclic right rotation
#ifndef ROTR32
#define ROTR32(x, y) (((x) >> (y)) ^ ((x) << (32 - (y))))
#endif
// little-endian byte access
#define B2S_GET32(p) \
(((uint32_t) ((uint8_t *) (p))[0]) ^ \
(((uint32_t) ((uint8_t *) (p))[1]) << 8) ^ \
(((uint32_t) ((uint8_t *) (p))[2]) << 16) ^ \
(((uint32_t) ((uint8_t *) (p))[3]) << 24))
// Mixing function G
#define B2S_G(a, b, c, d, x, y) { \
v[a] = v[a] + v[b] + x; \
v[d] = ROTR32(v[d] ^ v[a], 16); \
v[c] = v[c] + v[d]; \
v[b] = ROTR32(v[b] ^ v[c], 12); \
v[a] = v[a] + v[b] + y; \
v[d] = ROTR32(v[d] ^ v[a], 8); \
v[c] = v[c] + v[d]; \
v[b] = ROTR32(v[b] ^ v[c], 7); }
// Initialization Vector
static const uint32_t blake2s_iv[8] =
{
0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A,
0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19
};
// Compression function. "last" flag indicates last block.
static void blake2s_compress(blake2s_ctx *ctx, int last)
{
const uint8_t sigma[10][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 },
{ 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 }
};
int i;
uint32_t v[16], m[16];
for (i = 0; i < 8; i++) { // init work variables
v[i] = ctx->h[i];
v[i + 8] = blake2s_iv[i];
}
v[12] ^= ctx->t[0]; // low 32 bits of offset
v[13] ^= ctx->t[1]; // high 32 bits
if (last) // last block flag set ?
v[14] = ~v[14];
for (i = 0; i < 16; i++) // get little-endian words
m[i] = B2S_GET32(&ctx->b[4 * i]);
for (i = 0; i < 10; i++) { // ten rounds
B2S_G( 0, 4, 8, 12, m[sigma[i][ 0]], m[sigma[i][ 1]]);
B2S_G( 1, 5, 9, 13, m[sigma[i][ 2]], m[sigma[i][ 3]]);
B2S_G( 2, 6, 10, 14, m[sigma[i][ 4]], m[sigma[i][ 5]]);
B2S_G( 3, 7, 11, 15, m[sigma[i][ 6]], m[sigma[i][ 7]]);
B2S_G( 0, 5, 10, 15, m[sigma[i][ 8]], m[sigma[i][ 9]]);
B2S_G( 1, 6, 11, 12, m[sigma[i][10]], m[sigma[i][11]]);
B2S_G( 2, 7, 8, 13, m[sigma[i][12]], m[sigma[i][13]]);
B2S_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 state. key is optional
int blake2s_init(blake2s_ctx *ctx, size_t outlen,
const void *key, size_t keylen) // (keylen=0: no key)
{
size_t i;
if (outlen == 0 || outlen > 32 || keylen > 32)
return -1; // illegal parameters
for (i = 0; i < 8; i++) // state, "param block"
ctx->h[i] = blake2s_iv[i];
ctx->h[0] ^= 0x01010000 ^ (keylen << 8) ^ outlen;
ctx->t[0] = 0; // input count low word
ctx->t[1] = 0; // input count high word
ctx->c = 0; // pointer within buffer
ctx->outlen = outlen;
for (i = keylen; i < 64; i++) // zero input block
ctx->b[i] = 0;
if (keylen > 0) {
blake2s_update(ctx, key, keylen);
ctx->c = 64; // at the end
}
return 0;
}
// update with new data
void blake2s_update(blake2s_ctx *ctx,
const void *in, size_t inlen) // data bytes
{
size_t i;
for (i = 0; i < inlen; i++) {
if (ctx->c == 64) { // buffer full ?
ctx->t[0] += ctx->c; // add counters
if (ctx->t[0] < ctx->c) // carry overflow ?
ctx->t[1]++; // high word
blake2s_compress(ctx, 0); // compress (not last)
ctx->c = 0; // counter to zero
}
ctx->b[ctx->c++] = ((const uint8_t *) in)[i];
}
}
// finalize
void blake2s_final(blake2s_ctx *ctx, void *out)
{
size_t i;
ctx->t[0] += ctx->c; // mark last block offset
if (ctx->t[0] < ctx->c) // carry overflow
ctx->t[1]++; // high word
while (ctx->c < 64) // fill up with zeros
ctx->b[ctx->c++] = 0;
blake2s_compress(ctx, 1); // final block flag = 1
// little endian convert and store
for (i = 0; i < ctx->outlen; i++) {
((uint8_t *) out)[i] =
(ctx->h[i >> 2] >> (8 * (i & 3))) & 0xFF;
}
}
// convenience function for all-in-one computation
int blake2s(void *out, size_t outlen,
const void *key, size_t keylen,
const void *in, size_t inlen)
{
blake2s_ctx ctx;
if (blake2s_init(&ctx, outlen, key, keylen))
return -1;
blake2s_update(&ctx, in, inlen);
blake2s_final(&ctx, out);
return 0;
}
This module computes a series of keyed and unkeyed hashes from deterministically generated pseudo-random data, and computes a hash over those results. This is fairly a exhaustive, yet compact and fast method for verifying that the hashing module is functioning correctly.
Such testing is recommended especially when compiling the implementation for a new a target platform configuration. Furthermore, some security standards such as FIPS-140 may require a Power-On Self Test (POST) to be performed every time the cryptographic module is loaded [FIPS140-2IG].
// test_main.c
// Self test Modules for BLAKE2b and BLAKE2s -- and a stub main().
#include <stdio.h>
#include "blake2b.h"
#include "blake2s.h"
// Deterministic sequences (Fibonacci generator)
static void selftest_seq(uint8_t *out, size_t len, uint32_t seed)
{
size_t i;
uint32_t t, a , b;
a = 0xDEAD4BAD * seed; // prime
b = 1;
for (i = 0; i < len; i++) { // fill the buf
t = a + b;
a = b;
b = t;
out[i] = (t >> 24) & 0xFF;
}
}
// BLAKE2b self-test validation. Return 0 when OK.
int blake2b_selftest()
{
// grand hash of hash results
const uint8_t blake2b_res[32] = {
0xC2, 0x3A, 0x78, 0x00, 0xD9, 0x81, 0x23, 0xBD,
0x10, 0xF5, 0x06, 0xC6, 0x1E, 0x29, 0xDA, 0x56,
0x03, 0xD7, 0x63, 0xB8, 0xBB, 0xAD, 0x2E, 0x73,
0x7F, 0x5E, 0x76, 0x5A, 0x7B, 0xCC, 0xD4, 0x75
};
// parameter sets
const size_t b2b_md_len[4] = { 20, 32, 48, 64 };
const size_t b2b_in_len[6] = { 0, 3, 128, 129, 255, 1024 };
size_t i, j, outlen, inlen;
uint8_t in[1024], md[64], key[64];
blake2b_ctx ctx;
// 256-bit hash for testing
if (blake2b_init(&ctx, 32, NULL, 0))
return -1;
for (i = 0; i < 4; i++) {
outlen = b2b_md_len[i];
for (j = 0; j < 6; j++) {
inlen = b2b_in_len[j];
selftest_seq(in, inlen, inlen); // unkeyed hash
blake2b(md, outlen, NULL, 0, in, inlen);
blake2b_update(&ctx, md, outlen); // hash the hash
selftest_seq(key, outlen, outlen); // keyed hash
blake2b(md, outlen, key, outlen, in, inlen);
blake2b_update(&ctx, md, outlen); // hash the hash
}
}
// compute and compare the hash of hashes
blake2b_final(&ctx, md);
for (i = 0; i < 32; i++) {
if (md[i] != blake2b_res[i])
return -1;
}
return 0;
}
// BLAKE2s self-test validation. Return 0 when OK.
int blake2s_selftest()
{
// grand hash of hash results
const uint8_t blake2s_res[32] = {
0x6A, 0x41, 0x1F, 0x08, 0xCE, 0x25, 0xAD, 0xCD,
0xFB, 0x02, 0xAB, 0xA6, 0x41, 0x45, 0x1C, 0xEC,
0x53, 0xC5, 0x98, 0xB2, 0x4F, 0x4F, 0xC7, 0x87,
0xFB, 0xDC, 0x88, 0x79, 0x7F, 0x4C, 0x1D, 0xFE
};
// parameter sets
const size_t b2s_md_len[4] = { 16, 20, 28, 32 };
const size_t b2s_in_len[6] = { 0, 3, 64, 65, 255, 1024 };
size_t i, j, outlen, inlen;
uint8_t in[1024], md[32], key[32];
blake2s_ctx ctx;
// 256-bit hash for testing
if (blake2s_init(&ctx, 32, NULL, 0))
return -1;
for (i = 0; i < 4; i++) {
outlen = b2s_md_len[i];
for (j = 0; j < 6; j++) {
inlen = b2s_in_len[j];
selftest_seq(in, inlen, inlen); // unkeyed hash
blake2s(md, outlen, NULL, 0, in, inlen);
blake2s_update(&ctx, md, outlen); // hash the hash
selftest_seq(key, outlen, outlen); // keyed hash
blake2s(md, outlen, key, outlen, in, inlen);
blake2s_update(&ctx, md, outlen); // hash the hash
}
}
// compute and compare the hash of hashes
blake2s_final(&ctx, md);
for (i = 0; i < 32; i++) {
if (md[i] != blake2s_res[i])
return -1;
}
return 0;
}
// test driver
int main(int argc, char **argv)
{
printf("blake2b_selftest() = %s\n",
blake2b_selftest() ? "FAIL" : "OK");
printf("blake2s_selftest() = %s\n",
blake2s_selftest() ? "FAIL" : "OK");
return 0;
}