RFC 1319
The MD2 Message-Digest Algorithm
RFC 1319: The MD2 Message-Digest Algorithm 🦋
Okay bestie, this one is a classic 💖 It's RFC 1319, titled "The MD2 Message-Digest Algorithm." It was written by B. Kaliski from RSA Laboratories in the Network Working Group, and it's dated April 1992 📅. It's an informational doc, so it gives info to the Internet community and is not an Internet standard 🎀. It updates RFC 1115 ✨. The title block doesn't list anything it obsoletes, so there's nothing to report there 🌸.
Status of this Memo 💌
Quick status check: this memo gives information to the Internet community. It does not specify an Internet standard, and distribution of it is unlimited 🫶.
Acknowlegements 🫶
The description of MD2 is based on material prepared by John Linn and Ron Rivest. They gave permission to include that material, and it's really appreciated 💜.
Table of Contents 📚
1. Executive Summary 1
2. Terminology and Notation 2
3. MD2 Algorithm Description 2
4. Summary 4
References 5
APPENDIX A - Reference Implementation 5
Security Considerations 17
Author's Address 171. Executive Summary ✨
So the big picture: MD2 is a message-digest algorithm. You feed it an input message of any length, and it spits out a 128-bit "fingerprint" (aka "message digest") of that input 🔥. It's conjectured to be computationally infeasible to make two messages with the same digest, or to make any message that hits a specific target digest you've already picked 🙈. MD2 is meant for digital signatures, where a big file gets "compressed" securely before being signed with a private (secret) key under a public-key system like RSA 🔐.
License to use MD2 is granted for non-commerical Internet Privacy-Enhanced Mail [1-3] 💅.
This document updates the August 1989 RFC 1115 [3], which also includes a reference implementation of MD2. What's new here is that there's now a written description of MD2, and the reference implementation is more portable 🧚.
For OSI-based applications, MD2's object identifier is:
md2 OBJECT IDENTIFIER ::=
iso(1) member-body(2) US(840) rsadsi(113549) digestAlgorithm(2) 2}In the X.509 type AlgorithmIdentifier [4], the parameters for MD2 should have type NULL 🎀.
2. Terminology and Notation 🩷
In this doc, a "byte" is an eight-bit quantity 🍓.
We write x_i for "x sub i". If the subscript is an expression, you wrap it in braces, like x_{i+1}. Superscripts work the same way with ^, so x^i means x to the i-th power 🧮.
X xor Y means the bit-wise XOR of X and Y 💫.
3. MD2 Algorithm Description 🌈
Here's the setup: we start with a b-byte message as input, and we want to find its message digest. b is any nonnegative integer. b can be zero, and it can be arbitrarily large 🦄. Picture the bytes of the message written out like this:
m_0 m_1 ... m_{b-1}Computing the message digest takes five steps 👑.
3.1 Step 1. Append Padding Bytes 🎀
The message gets "padded" (extended) so its length in bytes is congruent to 0, modulo 16. In other words, the message gets stretched until it's a multiple of 16 bytes long. Padding happens every time, even if the message length is already congruent to 0, modulo 16 🙌.
Here's how padding works: "i" bytes of value "i" get appended to the message so the padded length becomes congruent to 0, modulo 16. At least one byte and at most 16 16 bytes are appended 🧁.
Once that's done, the resulting message has a length that is an exact multiple of 16 bytes. We write its bytes as M[0 ... N-1], where N is a multiple of 16 💖.
3.2 Step 2. Append Checksum 🧩
A 16-byte checksum of the message gets appended to the result of the previous step ✨.
This step uses a 256-byte "random" permutation built from the digits of pi. S[i] is the i-th element of that table, and the table is in the appendix 🥧.
Here's what you do:
/* Clear checksum. */
For i = 0 to 15 do:
Set C[i] to 0.
end /* of loop on i */
Set L to 0.
/* Process each 16-word block. */
For i = 0 to N/16-1 do
/* Checksum block i. */
For j = 0 to 15 do
Set c to M[i*16+j].
Set C[j] to S[c xor L].
Set L to C[j].
end /* of loop on j */
end /* of loop on i */The 16-byte checksum C[0 ... 15] is appended to the message. Let M[0 with checksum), where N' = N + 16 💅.
3.3 Step 3. Initialize MD Buffer 🫧
We use a 48-byte buffer X to compute the message digest. It gets initialized to zero 🌸.
3.4 Step 4. Process Message in 16-Byte Blocks 🌀
This step uses the same 256-byte permutation S that step 2 uses 🔁.
Here's the procedure:
/* Process each 16-word block. */
For i = 0 to N'/16-1 do
/* Copy block i into X. */
For j = 0 to 15 do
Set X[16+j] to M[i*16+j].
Set X[32+j] to (X[16+j] xor X[j]).
end /* of loop on j */
Set t to 0.
/* Do 18 rounds. */
For j = 0 to 17 do
/* Round j. */
For k = 0 to 47 do
Set t and X[k] to (X[k] xor S[t]).
end /* of loop on k */
Set t to (t+j) modulo 256.
end /* of loop on j */
end /* of loop on i */3.5 Step 5. Output 🏁
The output message digest is X[0 ... 15]. So we start at X[0] and end at X[15] 💜.
And that's the whole MD2 description! A reference implementation in C is in the appendix 🎀.
4. Summary 🌟
MD2 is simple to implement, and it gives you a "fingerprint" (message digest) of a message of any length 🥰. It's conjectured that coming up with two messages that share a digest takes on the order of 2^64 operations. Coming up with any message that matches a given digest takes on the order of 2^128 operations 🔐.
MD2 has been carefully scrutinized for weaknesses. But it's a relatively new algorithm, so more security analysis is of course justified, same as with any new proposal like this 🧐.
References 📖
[1] Linn, J., "Privacy Enhancement for Internet Electronic Mail: Part I -- Message Encipherment and Authentication Procedures", RFC 1113, DEC, IAB Privacy Task Force, August 1989.
[2] Kent, S., and J. Linn, "Privacy Enhancement for Internet Electronic Mail: Part II -- Certificate-Based Key Management", RFC 1114, BBNCC, DEC, IAB Privacy Task Force, August 1989.
[3] Linn, J., "Privacy Enhancement for Internet Electronic Mail: Part III -- Algorithms, Modes, and Identifiers", RFC 1115 DEC, IAB Privacy Task Force, August 1989.
[4] CCITT Recommendation X.509 (1988), "The Directory - Authentication Framework".
APPENDIX A - Reference Implementation 🧚♀️
This appendix has these files taken from RSAREF: A Cryptographic Toolkit for Privacy-Enhanced Mail:
global.h -- global header file
md2.h -- header file for MD2
md2c.c -- source code for MD2For more info on RSAREF, email <rsaref@rsa.com> 📧.
The appendix also includes this file:
mddriver.c -- test driver for MD2, MD4 and MD5The driver compiles for MD5 by default. It can also compile for MD2 or MD4 if the symbol MD is defined on the C compiler command line as 2 or 4 🛠️.
A.1 global.h 🌷
/* GLOBAL.H - RSAREF types and constants
*/
/* PROTOTYPES should be set to one if and only if the compiler supports
function argument prototyping.
The following makes PROTOTYPES default to 0 if it has not already
been defined with C compiler flags.
*/
#ifndef PROTOTYPES
#define PROTOTYPES 0
#endif
/* POINTER defines a generic pointer type */
typedef unsigned char *POINTER;
/* UINT2 defines a two byte word */
typedef unsigned short int UINT2;
/* UINT4 defines a four byte word */
typedef unsigned long int UINT4;
/* PROTO_LIST is defined depending on how PROTOTYPES is defined above.
If using PROTOTYPES, then PROTO_LIST returns the list, otherwise it
returns an empty list.
*/
#if PROTOTYPES
#define PROTO_LIST(list) list
#else
#define PROTO_LIST(list) ()
#endifA.2 md2.h 🦋
/* MD2.H - header file for MD2C.C
*/
/* Copyright (C) 1990-2, RSA Data Security, Inc. Created 1990. All
rights reserved.
License to copy and use this software is granted for
non-commercial Internet Privacy-Enhanced Mail provided that it is
identified as the "RSA Data Security, Inc. MD2 Message Digest
Algorithm" in all material mentioning or referencing this software
or this function.
RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.
These notices must be retained in any copies of any part of this
documentation and/or software.
*/
typedef struct {
unsigned char state[16]; /* state */
unsigned char checksum[16]; /* checksum */
unsigned int count; /* number of bytes, modulo 16 */
unsigned char buffer[16]; /* input buffer */
} MD2_CTX;
void MD2Init PROTO_LIST ((MD2_CTX *));
void MD2Update PROTO_LIST
((MD2_CTX *, unsigned char *, unsigned int));
void MD2Final PROTO_LIST ((unsigned char [16], MD2_CTX *));A.3 md2c.c 💻
/* MD2C.C - RSA Data Security, Inc., MD2 message-digest algorithm
*/
/* Copyright (C) 1990-2, RSA Data Security, Inc. Created 1990. All
rights reserved.
License to copy and use this software is granted for
non-commercial Internet Privacy-Enhanced Mail provided that it is
identified as the "RSA Data Security, Inc. MD2 Message Digest
Algorithm" in all material mentioning or referencing this software
or this function.
RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.
These notices must be retained in any copies of any part of this
documentation and/or software.
*/
#include "global.h"
#include "md2.h"
static void MD2Transform PROTO_LIST
((unsigned char [16], unsigned char [16], unsigned char [16]));
static void MD2_memcpy PROTO_LIST ((POINTER, POINTER, unsigned int));
static void MD2_memset PROTO_LIST ((POINTER, int, unsigned int));
/* Permutation of 0..255 constructed from the digits of pi. It gives a
"random" nonlinear byte substitution operation.
*/okay so this 256-entry table is the scrambler, bestie 🧚 it's a shuffled lookup that every byte gets pushed through, and it's giving "pi digits but make it a substitution box" 💅
static unsigned char PI_SUBST[256] = {
41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
31, 26, 219, 153, 141, 51, 159, 17, 131, 20
};next up is the PADDING array, which is the padding bytes for every possible leftover length, from zero all the way up to sixteen 🌸 each entry is just that many copies of its own length value, so the padding is always self-describing 🫶
static unsigned char *PADDING[] = {
(unsigned char *)"",
(unsigned char *)"\001",
(unsigned char *)"\002\002",
(unsigned char *)"\003\003\003",
(unsigned char *)"\004\004\004\004",
(unsigned char *)"\005\005\005\005\005",
(unsigned char *)"\006\006\006\006\006\006",
(unsigned char *)"\007\007\007\007\007\007\007",
(unsigned char *)"\010\010\010\010\010\010\010\010",
(unsigned char *)"\011\011\011\011\011\011\011\011\011",
(unsigned char *)"\012\012\012\012\012\012\012\012\012\012",
(unsigned char *)"\013\013\013\013\013\013\013\013\013\013\013",
(unsigned char *)"\014\014\014\014\014\014\014\014\014\014\014\014",
(unsigned char *)
"\015\015\015\015\015\015\015\015\015\015\015\015\015",
(unsigned char *)
"\016\016\016\016\016\016\016\016\016\016\016\016\016\016",
(unsigned char *)
"\017\017\017\017\017\017\017\017\017\017\017\017\017\017\017",
(unsigned char *)
"\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020\020"
};MD2Init, the fresh-start function ✨
okay so MD2Init is the "start a brand new digest" moment 🎀 it zeroes out the count, the state, and the checksum, so you begin with a totally clean slate, no cap
/* MD2 initialization. Begins an MD2 operation, writing a new context.
*/
void MD2Init (context)
MD2_CTX *context; /* context */
{
context->count = 0;
MD2_memset ((POINTER)context->state, 0, sizeof (context->state));
MD2_memset
((POINTER)context->checksum, 0, sizeof (context->checksum));
}MD2Update, feeding it more bytes 🦋
this one is the chunk-by-chunk worker, and it's lowkey the most iconic function here 👑 it keeps a running count mod 16, tops up any half-filled buffer, transforms every full sixteen-byte block it can, and then saves whatever's left over for next time 💜
/* MD2 block update operation. Continues an MD2 message-digest
operation, processing another message block, and updating the
context.
*/
void MD2Update (context, input, inputLen)
MD2_CTX *context; /* context */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
{
unsigned int i, index, partLen;
/* Update number of bytes mod 16 */
index = context->count;
context->count = (index + inputLen) & 0xf;
partLen = 16 - index;
/* Transform as many times as possible.
*/
if (inputLen >= partLen) {
MD2_memcpy
((POINTER)&context->buffer[index], (POINTER)input, partLen);
MD2Transform (context->state, context->checksum, context->buffer);
for (i = partLen; i + 15 < inputLen; i += 16)
MD2Transform (context->state, context->checksum, &input[i]);
index = 0;
}
else
i = 0;
/* Buffer remaining input */
MD2_memcpy
((POINTER)&context->buffer[index], (POINTER)&input[i],
inputLen-i);
}MD2Final, wrapping it all up 💅
periodt, this is the closing act 🌈 it pads the message out to a multiple of sixteen, appends the checksum, copies the state out as the digest, and then wipes the whole context so no secrets are hanging around 🙈
/* MD2 finalization. Ends an MD2 message-digest operation, writing the
message digest and zeroizing the context.
*/
void MD2Final (digest, context)
unsigned char digest[16]; /* message digest */
MD2_CTX *context; /* context */
{
unsigned int index, padLen;
/* Pad out to multiple of 16.
*/
index = context->count;
padLen = 16 - index;
MD2Update (context, PADDING[padLen], padLen);
/* Extend with checksum */
MD2Update (context, context->checksum, 16);
/* Store state in digest */
MD2_memcpy ((POINTER)digest, (POINTER)context->state, 16);
/* Zeroize sensitive information.
*/
MD2_memset ((POINTER)context, 0, sizeof (*context));
}MD2Transform, the main scrambling event 🔥
this is the heart of the whole thing, bestie 💖 it mixes the state, the input block, and their XOR into one 48-byte working buffer, runs eighteen rounds of scrambling through the PI_SUBST table, saves the new state, and then folds the block into the checksum, lowkey iconic behaviour 🦋
/* MD2 basic transformation. Transforms state and updates checksum
based on block.
*/
static void MD2Transform (state, checksum, block)
unsigned char state[16];
unsigned char checksum[16];
unsigned char block[16];
{
unsigned int i, j, t;
unsigned char x[48];
/* Form encryption block from state, block, state ^ block.
*/
MD2_memcpy ((POINTER)x, (POINTER)state, 16);
MD2_memcpy ((POINTER)x+16, (POINTER)block, 16);
for (i = 0; i < 16; i++)
x[i+32] = state[i] ^ block[i];
/* Encrypt block (18 rounds).
*/
t = 0;
for (i = 0; i < 18; i++) {
for (j = 0; j < 48; j++)
t = x[j] ^= PI_SUBST[t];
t = (t + i) & 0xff;
}
/* Save new state */
MD2_memcpy ((POINTER)state, (POINTER)x, 16);
/* Update checksum.
*/
t = checksum[15];
for (i = 0; i < 16; i++)
t = checksum[i] ^= PI_SUBST[block[i] ^ t];
/* Zeroize sensitive information.
*/
MD2_memset ((POINTER)x, 0, sizeof (x));
}The memory helpers, MD2_memcpy and MD2_memset 🧚
these two are just little byte-by-byte helpers, nothing fancy 🌸 the comments are literally saying "swap in the standard library version if you can," which is very self-aware of them 😭
/* Note: Replace "for loop" with standard memcpy if possible.
*/
static void MD2_memcpy (output, input, len)
POINTER output;
POINTER input;
unsigned int len;
{
unsigned int i;
for (i = 0; i < len; i++)
output[i] = input[i];
}
/* Note: Replace "for loop" with standard memset if possible.
*/
static void MD2_memset (output, value, len)
POINTER output;
int value;
unsigned int len;
{
unsigned int i;
for (i = 0; i < len; i++)
((char *)output)[i] = (char)value;
}A.4 mddriver.c 🎀
okay so this is the test driver, and it's giving "one program that can test MD2, MD4 or MD5, depending on what you compile it with" 💜 it defaults to MD5 unless you say otherwise, and you can feed it strings, files, stdin, a timing run, or the built-in test suite 🍓
/* MDDRIVER.C - test driver for MD2, MD4 and MD5
*/
/* Copyright (C) 1990-2, RSA Data Security, Inc. Created 1990. All
rights reserved.
RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.
These notices must be retained in any copies of any part of this
documentation and/or software.
*/
/* The following makes MD default to MD5 if it has not already been
defined with C compiler flags.
*/
#ifndef MD
#define MD MD5
#endif
#include <stdio.h>
#include <time.h>
#include <string.h>
#include "global.h"
#if MD == 2
#include "md2.h"
#endif
#if MD == 4
#include "md4.h"
#endif
#if MD == 5
#include "md5.h"
#endif
/* Length of test block, number of test blocks.
*/
#define TEST_BLOCK_LEN 1000
#define TEST_BLOCK_COUNT 1000
static void MDString PROTO_LIST ((char *));
static void MDTimeTrial PROTO_LIST ((void));
static void MDTestSuite PROTO_LIST ((void));
static void MDFile PROTO_LIST ((char *));
static void MDFilter PROTO_LIST ((void));
static void MDPrint PROTO_LIST ((unsigned char [16]));
#if MD == 2
#define MD_CTX MD2_CTX
#define MDInit MD2Init
#define MDUpdate MD2Update
#define MDFinal MD2Final
#endif
#if MD == 4
#define MD_CTX MD4_CTX
#define MDInit MD4Init
#define MDUpdate MD4Update
#define MDFinal MD4Final
#endif
#if MD == 5
#define MD_CTX MD5_CTX
#define MDInit MD5Init
#define MDUpdate MD5Update
#define MDFinal MD5Final
#endif
/* Main driver.
Arguments (may be any combination):
-sstring - digests string
-t - runs time trial
-x - runs test script
filename - digests file
(none) - digests standard input
*/
int main (argc, argv)
int argc;
char *argv[];
{
int i;
if (argc > 1)
for (i = 1; i < argc; i++)
if (argv[i][0] == '-' && argv[i][1] == 's')
MDString (argv[i] + 2);
else if (strcmp (argv[i], "-t") == 0)
MDTimeTrial ();
else if (strcmp (argv[i], "-x") == 0)
MDTestSuite ();
else
MDFile (argv[i]);
else
MDFilter ();
return (0);
}
/* Digests a string and prints the result.
*/
static void MDString (string)
char *string;
{
MD_CTX context;
unsigned char digest[16];
unsigned int len = strlen (string);
MDInit (&context);
MDUpdate (&context, string, len);
MDFinal (digest, &context);
printf ("MD%d (\"%s\") = ", MD, string);
MDPrint (digest);
printf ("\n");
}
/* Measures the time to digest TEST_BLOCK_COUNT TEST_BLOCK_LEN-byte
blocks.
*/
static void MDTimeTrial ()
{
MD_CTX context;
time_t endTime, startTime;
unsigned char block[TEST_BLOCK_LEN], digest[16];
unsigned int i;
printf
("MD%d time trial. Digesting %d %d-byte blocks ...", MD,
TEST_BLOCK_LEN, TEST_BLOCK_COUNT);
/* Initialize block */
for (i = 0; i < TEST_BLOCK_LEN; i++)
block[i] = (unsigned char)(i & 0xff);
/* Start timer */
time (&startTime);
/* Digest blocks */
MDInit (&context);
for (i = 0; i < TEST_BLOCK_COUNT; i++)
MDUpdate (&context, block, TEST_BLOCK_LEN);
MDFinal (digest, &context);
/* Stop timer */
time (&endTime);
printf (" done\n");
printf ("Digest = ");
MDPrint (digest);
printf ("\nTime = %ld seconds\n", (long)(endTime-startTime));
printf
("Speed = %ld bytes/second\n",
(long)TEST_BLOCK_LEN * (long)TEST_BLOCK_COUNT/(endTime-startTime));
}
/* Digests a reference suite of strings and prints the results.
*/
static void MDTestSuite ()
{
printf ("MD%d test suite:\n", MD);
MDString ("");
MDString ("a");
MDString ("abc");
MDString ("message digest");
MDString ("abcdefghijklmnopqrstuvwxyz");
MDString
("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
MDString
("1234567890123456789012345678901234567890\
1234567890123456789012345678901234567890");
}
/* Digests a file and prints the result.
*/
static void MDFile (filename)
char *filename;
{
FILE *file;
MD_CTX context;
int len;
unsigned char buffer[1024], digest[16];
if ((file = fopen (filename, "rb")) == NULL)
printf ("%s can't be opened\n", filename);
else {
MDInit (&context);
while (len = fread (buffer, 1, 1024, file))
MDUpdate (&context, buffer, len);
MDFinal (digest, &context);
fclose (file);
printf ("MD%d (%s) = ", MD, filename);
MDPrint (digest);
printf ("\n");
}
}
/* Digests the standard input and prints the result.
*/
static void MDFilter ()
{
MD_CTX context;
int len;
unsigned char buffer[16], digest[16];
MDInit (&context);
while (len = fread (buffer, 1, 16, stdin))
MDUpdate (&context, buffer, len);
MDFinal (digest, &context);
MDPrint (digest);
printf ("\n");
}
/* Prints a message digest in hexadecimal.
*/
static void MDPrint (digest)
unsigned char digest[16];
{
unsigned int i;
for (i = 0; i < 16; i++)
printf ("%02x", digest[i]);
}A.5 Test suite 🧪
okay so the test suite is the receipts 🧾 run the driver with "-x" and you should get exactly these digests back, so you can check your build is legit before you trust it 💅
MD2 test suite:
MD2 ("") = 8350e5a3e24c153df2275c9f80692773
MD2 ("a") = 32ec01ec4a6dac72c0ab96fb34c0b5d1
MD2 ("abc") = da853b0d3f88d99b30283a69e6ded6bb
MD2 ("message digest") = ab4f496bfb2a530b219ff33031fe06b0
MD2 ("abcdefghijklmnopqrstuvwxyz") = 4e8ddff3650292ab5a4108c3aa47940b
MD2 ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") =
da33def2a42df13975352846c30338cd
MD2 ("123456789012345678901234567890123456789012345678901234567890123456
78901234567890") = d5976f79d83d3a0dc9806c3c66f3efd8Security Considerations 🔐
okay bestie, this part is serious 😭 the author says the level of security in this memo is considered sufficient for implementing very high security hybrid digital signature schemes based on MD2 and a public-key cryptosystem. that's a big claim, so take it seriously 💜
Author's Address 🌸
this is who wrote it, the legend Burton S. Kaliski Jr. at RSA Laboratories, a division of RSA Data Security, Inc.
Burton S. Kaliski Jr.
RSA Laboratories (a division of RSA Data Security, Inc.)
10 Twin Dolphin Drive
Redwood City, CA 94065
Phone: (415) 595-8782
FAX: (415) 595-4126
EMail: burt@rsa.com📦 where this page comes from
- ietf: rfc1319 1992-04
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms