DLI Implementation and Reference Guide - Datalogics

A.164 DLI Reference Guide
certificate type.
2 The last parameter is a required callback function. This function will be called
during the dlpdfdocwritepdf function call. It will be passed a character string
Concepts and Facilities: Guide to the DL Pager Composition System
containing the SHA-1 hash for the PDF file being written, as a NULL-terminated
string of hexadecimal digits using PKCS #1 padding, containing a BER OID
(object identifier) for the SHA-1 algorithm. The buffer is 256 bytes long (not
including the NULL terminator), and formatted as
0001FFFF .. FF003021300906052B0E03021A05000414
[ 40 hex digits for SHA-1 hash ]
The callback function must encrypt this hash value with the private key
corresponding to the public key in the signature's x.509 certificate, and fill the
buffer passed in with 256 hexadecimal digits representing the encrypted value for
the supplied BER formatted hash. A 1024-bit key is used for encryption
operations. Note that the signed hash will not have padding, and must be exactly
256 hexadecimal digits. Zeros must be used for padding, if required.