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LibPDF: Implement 7.6.4.4.10 Algorithm 11: Authenticating user password

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...for handlers of revision 6.
This commit is contained in:
Nico Weber 2023-07-18 10:35:12 -04:00 • committed by Andreas Kling
parent f23a394aac
commit 8f6c67a71c
1 changed files with 7 additions and 2 deletions
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9
Userland/Libraries/LibPDF/Encryption.cpp
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@ -276,7 +276,7 @@ bool StandardSecurityHandler::authenticate_user_password_r2_to_r5(StringView pas
return u_bytes == password_buffer.bytes();
}
bool StandardSecurityHandler::authenticate_user_password_r6_and_later(StringView)
bool StandardSecurityHandler::authenticate_user_password_r6_and_later(StringView password)
{
// ISO 32000 (PDF 2.0), 7.6.4.4.10 Algorithm 11: Authenticating the user password (Security handlers of
// revision 6)
@ -286,7 +286,12 @@ bool StandardSecurityHandler::authenticate_user_password_r6_and_later(StringView
// concatenated with the 8 bytes of User Validation Salt (see 7.6.4.4.7, "Algorithm 8: Computing the
// encryption dictionary's U (user password) and UE (user encryption) values (Security handlers of
// revision 6)"). If the 32- byte result matches the first 32 bytes of the U string, this is the user password.
TODO();
ByteBuffer input;
input.append(password.bytes());
input.append(m_u_entry.bytes().slice(32, 8)); // See comment in compute_encryption_key_r6_and_later() re "Validation Salt".
auto hash = computing_a_hash_r6_and_later(input, password, HashKind::User);
return hash == m_u_entry.bytes().trim(32);
}
bool StandardSecurityHandler::try_provide_user_password(StringView password_string)