Patch 25440397: QUARTERLY FULL STACK DOWNLOAD PATCH FOR EXADATA (Apr 2017 – 12.1.0.2) As a rule of thumb, you should always checksum your downloads, to ensure they are free of corruption. The reader should refer to “ Optional Extensions to 256 and 320 Hash Results: RIPEMD-256 and RIPEMD-320” for details.As a DBA, in your time, you will need to download files such as Oracle binaries, patches, etc. RIPEMD-256 and RIPEMD-320 simply generate more entropy for a given Message M. For example, RIPEMD-128 is as cryptographically strong as RIPEMD-256 RIPEMD-160 is as cryptographically strong as RIPEMD-320. Note that hash length does not necessarily equate to strength. The match algorithm terminates on a first match, so only the strongest hash is displayed. Internally, the DLL searches for matching hash values in order from strongest to weakest (SHA-256 to MD4). When verifying, the extension DLL uses MD4, MD5, RIPEMD-128, SHA-1, HAVAL, RIPEMD-160, and SHA-256. An unverified file will diplay the message “Unverified Checksum”. A verified file will display the message “Verified Checksum” with a digest of the checksum. The message box will group files in two catagories: verified and unverified. Navigate to the files, right-click, and select Verify Checksum.Ī Message Box will be presented similar to that shown below. Navigate to the web page or document where the checksum resides, highlight, and Copy to the Clipboard. Verifying a file’s checkum is equally trivial. Pasting into Notepad from the Clipboard reveals the full text. The full Checksums are placed on the Windows Clipboard for pasting. A digest (truncated version) is displayed to keep the Message Box size manageable. If the user selects Create Checksum, MD5, SHA-1, RIPEMD-160, and SHA-256, hashes are created of the selected file or files and a Message Box is displayed with a digest of the hashed file or files. Once the DLLs are registered, they are avialable as Context Menus when one right-clicks a file (or multiple files) in Windows Explorer. Download the DLL (CtxCreateHashDll.zip or CtxVerifyHashDll.zip).Should the reader desire to use the Extension DLLs, he or she should: Microsoft offers a command line file checksum tool published under Knowledge Base article Q841290,”Availability and Description of the File Checksum Integrity Verifier Utility.” The Microsoft tool supports MD5 or SHA1. Creating CreateHash and VerifyHash Shell Context Menu Extension Dlls.Debugging and Managing an Unstable Explorer.exe.Creating a Shell Context Menu Extension DLL.Compiling and Integrating Crypto++ into the Visual C++ Environment.This article will discuss the following topics: The article is based on Michael Dunn’s “ Guide to Writing Shell Extensions, Part I” and Tom Archer’s “ Using the Clipboard, Part I: Transferring Simple Text” and “ Crypto++.” This article presents two Shell Extension DLLs that can be used to create file checksums and verify file checksums. To detect tampering (and transmission errors), one generally chooses a cryptographic Hash due to the desireable property of Collision Resistance. To detect transmission errors, one could use a CRC (cyclic redundancy check). Checksumming detects both transmission errors and tampering. A file Checksum is used to verify the integrity of a file.
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