U c#@sddlZddlmZddlmZddlmZddlmZdZ ddZ ee e fe d d d Z d d ZddZddZedddZde eee dddZdS)N)md5)Union)generic) rc4_encrypts (N^NuAdNV..h>/ dSizc Cs|tdd}t|}||td|}|||||dkrX|sX|d|}|dkrtdD]} t|d|}qp|d|S)z{ Implementation of algorithm 3.2 of the PDF standard security handler, section 3.5.2 of the PDF 1.6 reference. N \sz)compute_o_value_legacy..)compute_o_value_legacy_prepr rrbytes)Z owner_pwdZuser_pwdrrkeyvalnew_keyrr(rcompute_o_value_legacyFs   r/cCsR|tdd}t|}|}|dkrBtdD]}t|}q0|d|}|S)z$ Steps 1-4 of algorithm 3.3 Nrr r )r rrr)rrrrrrr,rrrr*cs  r*c Cs(t|dd|||dd}t|t}||fS){ Implementation of algorithm 3.4 of the PDF standard security handler, section 3.5.2 of the PDF 1.6 reference. Tr)rrr )rrrrr,urrrcompute_u_value_r2}s   r5r3c s~t|||||||d}t}|t|||} t|| } tddD]$tfdd|D} t| | } qL| d|fS)r0r3r"r#c3s|]}|AVqdSr$rr%r(rrr)sz&compute_u_value_r34..s)rrr r rrrr+) rrrrrrrr,rrr-r.rr(rcompute_u_value_r34s     r6F) shared_keyidnum generationrcCs~td|dd}td|dd}|||}t|t|dksLt|rX|d7}t|}|dtdt|dS)a Function that does the key derivation for PDF's legacy security handlers. :param shared_key: Global file encryption key. :param idnum: ID of the object being written. :param generation: Generation number of the object being written. :param use_aes: Boolean indicating whether the security handler uses RC4 or AES(-128). :return: rNr r1r2ssAlT)r rlenAssertionErrorrrmin)r7r8r9Zuse_aesZpack1Zpack2r,rrrrlegacy_derive_object_keys  r>)F)r hashlibrtypingrZpyhanko.pdf_utilsrZpyhanko.pdf_utils.crypt._utilrr rr r+r!r/r*r5boolr6intr>rrrrs"    0 +