This library implements some hash and cryptographic algorithms.

Dependents:   mBuinoBlinky PB_Emma_Ethernet SLOTrashHTTP Garagem ... more

This library implements the following algorithms :

  • RC4
  • AES (AES-128, AES-192, AES-256)
  • DES
  • Triple DES (EDE)
  • MD2
  • MD4
  • MD5
  • SHA-1
  • SHA-2 (SHA-224, SHA-256, SHA-384, SHA-512)

The hash algorithms have been optimized for the mbed and you should get decent performance. However, I did not optimize the ciphers. Also, I did not test extensively these algorithms : it should work but you may find some bugs. Block ciphers support two modes : ECB and CBC.

Warning

If you are using SHA-384 or SHA-512, be aware that it produces large binary files and the compilation (using the online compiler) takes much longer to execute. It may happen that the compiler stops because it timed-out. In this case, just compile again and it should work.

Computing hash

You can compute the hash of some data in two different ways. The first one is the easiest, each hash algorithm has a static method that takes some data and compute the hash from it.

Computing hash using method 1

#include "Crypto.h"
#include "mbed.h"

static const char msg[] = "mbed is great !";

int main()
{
    uint8_t hash[16];
    MD2::computeHash(hash, (uint8_t*)msg, strlen(msg));
    printf("hash: ");
    for(int i = 0; i < 16; ++i)
        printf("%02x", hash[i]);
    printf("\n");
    
    return 0;
}

The second one is slightly slower (around 2-3% slower) but it allows you to compute the hash of some data in several steps (by calling update method). This is the method you should use if you need to compute the hash from a large source and you don't have enough memory to store it in a single buffer.

Computing hash using method 2

#include "Crypto.h"
#include "mbed.h"

static const char msg[] = "mbed is great !";

int main()
{
    uint8_t hash[16];
    MD2 h;
    h.update((uint8_t*)msg, strlen(msg));
    h.finalize(hash);
    printf("hash: ");
    for(int i = 0; i < 16; ++i)
        printf("%02x", hash[i]);
    printf("\n");
    
    return 0;
}

TODO

  • optimize ciphers
  • add doc

hash/MD2.cpp

Committer:
feb11
Date:
2014-05-11
Revision:
13:ac8e23b98dae
Parent:
10:bc9c23aa3870

File content as of revision 13:ac8e23b98dae:

/**
    Implementation of MD2 as described here:
    http://tools.ietf.org/html/rfc1319
*/

#include "MD2.h"
#include <string.h>


static const uint8_t s[] =
{
    0x29, 0x2E, 0x43, 0xC9, 0xA2, 0xD8, 0x7C, 0x01, 0x3D, 0x36, 0x54, 0xA1, 0xEC, 0xF0, 0x06, 0x13, 
    0x62, 0xA7, 0x05, 0xF3, 0xC0, 0xC7, 0x73, 0x8C, 0x98, 0x93, 0x2B, 0xD9, 0xBC, 0x4C, 0x82, 0xCA, 
    0x1E, 0x9B, 0x57, 0x3C, 0xFD, 0xD4, 0xE0, 0x16, 0x67, 0x42, 0x6F, 0x18, 0x8A, 0x17, 0xE5, 0x12, 
    0xBE, 0x4E, 0xC4, 0xD6, 0xDA, 0x9E, 0xDE, 0x49, 0xA0, 0xFB, 0xF5, 0x8E, 0xBB, 0x2F, 0xEE, 0x7A, 
    0xA9, 0x68, 0x79, 0x91, 0x15, 0xB2, 0x07, 0x3F, 0x94, 0xC2, 0x10, 0x89, 0x0B, 0x22, 0x5F, 0x21,
    0x80, 0x7F, 0x5D, 0x9A, 0x5A, 0x90, 0x32, 0x27, 0x35, 0x3E, 0xCC, 0xE7, 0xBF, 0xF7, 0x97, 0x03, 
    0xFF, 0x19, 0x30, 0xB3, 0x48, 0xA5, 0xB5, 0xD1, 0xD7, 0x5E, 0x92, 0x2A, 0xAC, 0x56, 0xAA, 0xC6, 
    0x4F, 0xB8, 0x38, 0xD2, 0x96, 0xA4, 0x7D, 0xB6, 0x76, 0xFC, 0x6B, 0xE2, 0x9C, 0x74, 0x04, 0xF1, 
    0x45, 0x9D, 0x70, 0x59, 0x64, 0x71, 0x87, 0x20, 0x86, 0x5B, 0xCF, 0x65, 0xE6, 0x2D, 0xA8, 0x02, 
    0x1B, 0x60, 0x25, 0xAD, 0xAE, 0xB0, 0xB9, 0xF6, 0x1C, 0x46, 0x61, 0x69, 0x34, 0x40, 0x7E, 0x0F, 
    0x55, 0x47, 0xA3, 0x23, 0xDD, 0x51, 0xAF, 0x3A, 0xC3, 0x5C, 0xF9, 0xCE, 0xBA, 0xC5, 0xEA, 0x26, 
    0x2C, 0x53, 0x0D, 0x6E, 0x85, 0x28, 0x84, 0x09, 0xD3, 0xDF, 0xCD, 0xF4, 0x41, 0x81, 0x4D, 0x52, 
    0x6A, 0xDC, 0x37, 0xC8, 0x6C, 0xC1, 0xAB, 0xFA, 0x24, 0xE1, 0x7B, 0x08, 0x0C, 0xBD, 0xB1, 0x4A, 
    0x78, 0x88, 0x95, 0x8B, 0xE3, 0x63, 0xE8, 0x6D, 0xE9, 0xCB, 0xD5, 0xFE, 0x3B, 0x00, 0x1D, 0x39, 
    0xF2, 0xEF, 0xB7, 0x0E, 0x66, 0x58, 0xD0, 0xE4, 0xA6, 0x77, 0x72, 0xF8, 0xEB, 0x75, 0x4B, 0x0A, 
    0x31, 0x44, 0x50, 0xB4, 0x8F, 0xED, 0x1F, 0x1A, 0xDB, 0x99, 0x8D, 0x33, 0x9F, 0x11, 0x83, 0x14
};


MD2::MD2():
HashAlgorithm(),
bufferLength(0),
l(0)
{
    memset(checksum, 0, 16);
    memset(x, 0, 16);
}

uint8_t MD2::outputSize() const
{
    return 16;
}

void MD2::update(uint8_t *data, uint32_t length)
{ 
    if(bufferLength == 0)
    {
        while(length >= 16)
        {
            computeBlock(checksum, x, &l, data);
            length -= 16;
            data += 16;
        }
        bufferLength = length;
        memcpy(buffer, data, length);
    }
    else if((int)length < 16-bufferLength)
    {
        memcpy(&buffer[bufferLength], data, length);
        bufferLength += length;
    }
    else
    {
        int offset = 16-bufferLength;
        memcpy(&buffer[bufferLength], data, offset);
        computeBlock(checksum, x, &l, buffer);
        data += offset;
        length -= offset;
        while(length >= 16)
        {
            computeBlock(checksum, x, &l, data);
            data += 16;
            length -= 16;
        }
        bufferLength = length;
        memcpy(buffer, &data, length);
    }
    
}

void MD2::finalize(uint8_t *hash)
{
    // compute what's left data the buffer
    int padding = 16 - bufferLength;
    memset(&buffer[bufferLength], padding, padding);
    computeBlock(checksum, x, &l, buffer);
    computeBlock(checksum, x, &l, checksum);
    memcpy(hash, x, 16);

    uint32_t *x2 = (uint32_t*)x;
    uint32_t *checksum2 = (uint32_t*)checksum;

    // reset state
    bufferLength = 0;
    l = 0;
    checksum2[0] = x2[0] = 0;
    checksum2[1] = x2[1] = 0;
    checksum2[2] = x2[2] = 0;
    checksum2[3] = x2[3] = 0;
}

void MD2::computeHash(uint8_t *hash, uint8_t *data, uint32_t length)
{
    uint8_t x[48];
    uint8_t checksum[16];
    uint8_t buffer[16];
    memset(x, 0, 16);
    memset(checksum, 0, 16);
    uint8_t l = 0;
    while(length >= 16)
    {
        computeBlock(checksum, x, &l, data);
        length -= 16;
        data += 16;
    }

    memcpy(buffer, data, length);
    uint8_t padding = 16-length;
    memset(&buffer[length], padding, padding);
    computeBlock(checksum, x, &l, buffer);
    computeBlock(checksum,x, &l, checksum);
    memcpy(hash, x, 16);
}

#ifdef __CC_ARM
__forceinline 
#endif
void MD2::computeBlock(uint8_t *checksum2, uint8_t *x2, uint8_t *l2, uint8_t *buffer2)
{
    if(checksum2 != buffer2)
    {
        #ifdef __CC_ARM
            #pragma unroll_completely   
        #endif
        for(int j = 0; j < 16; ++j)
        {
            uint8_t c = buffer2[j];
            *l2 = (checksum2[j] ^= s[c^(*l2)]);
        }
    }
    
    uint32_t *x3 = (uint32_t*)x2;
    uint32_t *buffer3 = (uint32_t*)buffer2;
    
    x3[4] = buffer3[0];
    x3[5] = buffer3[1];
    x3[6] = buffer3[2];
    x3[7] = buffer3[3];
    for(int j = 0; j < 4; ++j)
        x3[8+j] = x3[4+j] ^ x3[j];
    
    uint8_t t = 0;
    #ifdef __CC_ARM
        #pragma unroll_completely   
    #endif
    for(int j = 0; j < 18; ++j)
    {
        t = (x2[0] ^= s[t]);
        t = (x2[1] ^= s[t]);
        t = (x2[2] ^= s[t]);
        t = (x2[3] ^= s[t]);
        t = (x2[4] ^= s[t]);
        t = (x2[5] ^= s[t]);
        t = (x2[6] ^= s[t]);
        t = (x2[7] ^= s[t]);
        t = (x2[8] ^= s[t]);
        t = (x2[9] ^= s[t]);
        t = (x2[10] ^= s[t]);
        t = (x2[11] ^= s[t]);
        t = (x2[12] ^= s[t]);
        t = (x2[13] ^= s[t]);
        t = (x2[14] ^= s[t]);
        t = (x2[15] ^= s[t]);
        t = (x2[16] ^= s[t]);
        t = (x2[17] ^= s[t]);
        t = (x2[18] ^= s[t]);
        t = (x2[19] ^= s[t]);
        t = (x2[20] ^= s[t]);
        t = (x2[21] ^= s[t]);
        t = (x2[22] ^= s[t]);
        t = (x2[23] ^= s[t]);            
        t = (x2[24] ^= s[t]);
        t = (x2[25] ^= s[t]);
        t = (x2[26] ^= s[t]);
        t = (x2[27] ^= s[t]);
        t = (x2[28] ^= s[t]);
        t = (x2[29] ^= s[t]);
        t = (x2[30] ^= s[t]);
        t = (x2[31] ^= s[t]);
        t = (x2[32] ^= s[t]);
        t = (x2[33] ^= s[t]);
        t = (x2[34] ^= s[t]);
        t = (x2[35] ^= s[t]);
        t = (x2[36] ^= s[t]);
        t = (x2[37] ^= s[t]);
        t = (x2[38] ^= s[t]);
        t = (x2[39] ^= s[t]);
        t = (x2[40] ^= s[t]);
        t = (x2[41] ^= s[t]);
        t = (x2[42] ^= s[t]);
        t = (x2[43] ^= s[t]);
        t = (x2[44] ^= s[t]);
        t = (x2[45] ^= s[t]);
        t = (x2[46] ^= s[t]);
        t = (x2[47] ^= s[t]);            
        
        t += j;
    }
}