Peter,
Not sure if this is any help at all, but I am struggling through the
CryptoAPI myself at the moment and came across this code excerpt
// Determine number of bytes to encrypt at a time. This must
be a multiple
// of ENCRYPT_BLOCK_SIZE.
dwBlockLen:=1000-1000 mod ENCRYPT_BLOCK_SIZE;
// Determine the block size. If a block cipher is used this
must have
// room for an extra block.
if ENCRYPT_BLOCK_SIZE>1 then
dwBufferLen:=dwBlockLen+ENCRYPT_BLOCK_SIZE
else
dwBufferLen:=dwBlockLen;
Does this help, It doesn't apply to me as I am using RC4 with an
ENCRYPT_BLOCK_SIZE of 1.
Michael Darling
Solutions Analyst/Developer
ROOM Solutions Ltd
mailto:[EMAIL PROTECTED]
-----Original Message-----
From: Peter Laman [mailto:[EMAIL PROTECTED] wrote
Hello,
I'm trying to use the MS CryptoAPI to encrypt/decrypt a large amount of
data. Because of the size of the data, I use a RC2 block cipher
repeatedly. Both the calls to CryptEncrypt and CryptDecrypt specify a
hash, so the data can be checked. Now the encrypting/decrypting is OK,
until the last block. When I try to decrypt the final block,
CryptDecrypt returns rubbish after having correctly decrypting all
preceding blocks of data. Only with small data, < 1 block, the
decryption is OK. Has anybody experienced this before?
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