Blowfish algorithm problem with OpenSSL 1.0.0e (32-bit)

[Jussi Peltonen]

Hello,

newbie question regarding the Blowfish algorithm: why do my
encrypt/decypt functions fail on Windows XP SP3 with OpenSSL 1.0.0e?
The same functions work on my Linux workstation.

Windows output:
============
Encrypt:
encrypting 7680 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 512 bytes
EVP_DecryptFinal 8 bytes
encrypted 7744 bytes

Decrypt:
decrypting 7744 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1032 bytes        <= why 1032 instead of 1024?
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1032 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1032 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1032 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1032 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1032 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 520 bytes
EVP_DecryptFinal 0 bytes
decrypted 7736 bytes

Linux output:
==========
encrypting 7680 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 8 bytes
EVP_DecryptUpdate 512 bytes
EVP_DecryptFinal 8 bytes
encrypted 7744 bytes

decrypting 7744 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 1024 bytes
EVP_DecryptFinal 0 bytes
EVP_DecryptUpdate 512 bytes
EVP_DecryptFinal 0 bytes
decrypted 7680 bytes


Source code:

static int
decrypt (unsigned char *inbuf, int size, unsigned char *outbuf,
                 int *outsz)
{
        int olen, tlen, n, left;
        unsigned char *inp = inbuf;
        unsigned char *outp = outbuf;
        EVP_CIPHER_CTX ctx;

        printf("decrypting %d bytes\n", size);

        EVP_CIPHER_CTX_init (&ctx);
        EVP_DecryptInit (&ctx, EVP_bf_cbc (), key, iv);

        left = size;
        *outsz = 0;

        while (left > 0)
        {
                n = (left > OP_SIZE ? OP_SIZE : left);
                olen = 0;
                memset((void *)outp, 0, IP_SIZE);
                if (EVP_DecryptUpdate (&ctx, outp, &olen, inp, n) != 1)
                {
                        return -1;
                }
                printf("EVP_DecryptUpdate %d bytes\n", olen);

                if (EVP_DecryptFinal (&ctx, outp + olen, &tlen) != 1)
                {
                        return -1;
                }
                printf("EVP_DecryptFinal %d bytes\n", tlen);

                *outsz = ((*outsz) + olen + tlen);
                inp += n;
                left -= n;
                outp += (olen + tlen);
        }

        printf("decrypted %d bytes\n", *outsz);

        EVP_CIPHER_CTX_cleanup (&ctx);
        return 0;
}

static int
encrypt (unsigned char *inbuf, int size, unsigned char *outbuf, int *outsz)
{
        int olen, tlen, n, left;
        unsigned char *inp = inbuf;
        unsigned char *outp = outbuf;
        EVP_CIPHER_CTX ctx;

        printf("encrypting %d bytes\n", size);

        EVP_CIPHER_CTX_init (&ctx);
        EVP_EncryptInit (&ctx, EVP_bf_cbc (), key, iv);


        left = size;
        *outsz = 0;

        while (left > 0)
        {
                n = (left > IP_SIZE ? IP_SIZE : left);
                olen = 0;
                if (EVP_EncryptUpdate (&ctx, outp, &olen, inp, n) != 1)
                {
                        return -1;
                }
                printf("EVP_DecryptUpdate %d bytes\n", olen);

                if (EVP_EncryptFinal (&ctx, outp + olen, &tlen) != 1)
                {
                        return -1;
                }
                printf("EVP_DecryptFinal %d bytes\n", tlen);

                *outsz = ((*outsz) + olen + tlen);
                inp += n;
                left -= n;
                outp += (olen + tlen);
        }

        printf("encrypted %d bytes\n", *outsz);

        EVP_CIPHER_CTX_cleanup (&ctx);
        return 0;
}

Cheers,
Jussi
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