U Óøïc¨1ã @s6dZddlZddlmZddlmZmZddlmZm Z m Z ddl m Z zddlm Z Wn ek rxddlm Z YnXd Zdee d ee ee eed œd d„Zeee d eedœdd„Zee d eedœdd„Zee ee eeefdœdd„Zee d ee ee eeeefd œdd„Zeeefeedœdd„ZdS)z,Anything related to encryption / decryption.éN)Úmd5)ÚTupleÚUnioné)Úb_Úord_Ústr_)ÚByteStringObject)ÚLiterals (¿N^NuŠAdNVÿú..¶Ðh>€/ ©þdSizT)ééé)ÚpasswordÚrevÚkeylenÚ owner_entryÚp_entryÚ id1_entryÚmetadata_encryptÚreturnc Cs¦tt|ƒttƒdd…ƒ}t|ƒ}| |j¡t d|¡} | | ¡| |j¡|dkrh|sh| d¡| ¡} |dkršt dƒD]} t| d|…ƒ ¡} q€| d|…S)a Implementation of algorithm 3.2 of the PDF standard security handler. See section 3.5.2 of the PDF 1.6 reference. Args: password: The encryption secret as a bytes-string rev: The encryption revision (see PDF standard) keylen: owner_entry: p_entry: A set of flags specifying which operations shall be permitted when the document is opened with user access. If bit 2 is set to 1, all other bits are ignored and all operations are permitted. If bit 2 is set to 0, permission for operations are based on the values of the remaining flags defined in Table 24. id1_entry: metadata_encrypt: (Default value = True) Returns: An MD5 hash of keylen characters. Né zœsz_alg33..)Ú_alg33_1rrrÚ RC4_encryptrÚjoin)r&r'rrÚkeyZuser_password_bytesÚvalÚnew_keyr#r,r$Ú_alg33|s   r5)rrrrcCsZt|ttƒdd…ƒ}t|ƒ}| ¡}|dkrJtdƒD]}t|ƒ ¡}q8|d|…}|S)zÆ Steps 1-4 of algorithm 3.3. Args: password: rev: The encryption revision (see PDF standard) keylen: Returns: A transformed version of the password Nrr r)rrrrrr)rrrrr r!r"r2r#r#r$r/£s  r/)rrrrrcCs,d}d}t||||||ƒ}t|tƒ}||fS)af Implementation of algorithm 3.4 of the PDF standard security handler. See section 3.5.2 of the PDF 1.6 reference. Args: password: owner_entry: p_entry: A set of flags specifying which operations shall be permitted when the document is opened with user access. If bit 2 is set to 1, all other bits are ignored and all operations are permitted. If bit 2 is set to 0, permission for operations are based on the values of the remaining flags defined in Table 24. id1_entry: Returns: A Tuple (u-value, key) r é)r%r0r)rrrrrrr2ÚUr#r#r$Ú_alg34Äs  r8cCsŒt||||||ƒ}tƒ}| t¡| |j¡| ¡} t|| ƒ} tddƒD]4} d} |D]} | tt t | ƒ| Aƒƒ7} qVt| | ƒ} qJ| d|fS)aÐ Implementation of algorithm 3.4 of the PDF standard security handler. See section 3.5.2 of the PDF 1.6 reference. Args: password: rev: The encryption revision (see PDF standard) keylen: owner_entry: p_entry: A set of flags specifying which operations shall be permitted when the document is opened with user access. If bit 2 is set to 1, all other bits are ignored and all operations are permitted. If bit 2 is set to 0, permission for operations are based on the values of the remaining flags defined in Table 24. id1_entry: metadata_encrypt: A boolean Returns: A tuple (value, key) rr(ós) r%rrrrrr0rrr*r)rrrrrrrr2r r!r3r-r4Úkr#r#r$Ú_alg35ês     r;)r2Ú plaintextrcCsättdƒƒ}d}tdƒD]B}|||t||t|ƒƒd}||||||<||<qd\}}g}|D]l}|dd}|||d}||||||<||<|||||d}| ttt|ƒ|Aƒƒ¡qld |¡S)Nér)rrrr9)ÚlistrrÚlenÚappendrr*r1)r2r<ÚSÚjr-ÚretvalZplaintext_charÚtr#r#r$r0,s  $ r0)T)Ú__doc__rÚhashlibrÚtypingrrÚ_utilsrrrZgenericr r Ú ImportErrorZtyping_extensionsrÚstrÚintÚboolÚbytesr%r5r/r8r;r0r#r#r#r$ÚsZ  ÿùø Gþ '" û ' ø B