It is always important to verify whether the large file you downloaded is actually the file you expected to download or not. This is because files may change in some way from the original, while downloading. This may be due to corruption, due to errors in the download process. The downloaded files may even possess security-compromising features or include unwanted malicious software such as virus or a malware.
Therefore, no matter what the reason is, you should check the integrity of the files first. You should also check if there is any change from the original form or not. There are various ways by which you can check the original form. For instance, you can check if a file has a digital signature or not or check the hash value of it.
Check the hash value
Some web pages offering programs to download provide a long code called as MD5 near the program link. When you apply a cryptographic hash function to it, a string value is returned which is only valid for that file in the current state. If you download the same file with changed data (at very few places only) from some other website and apply this cryptographic function again, you will observe the value is changed. So, you can easily determine if the file is untouched or not.
Luckily, there are many programs available for Windows that help you calculate the hash value and check if the hash value you have of files matches or not. I am covering three free file integrity checkers here.
File Integrity Checkers
It is a free SHA-1, MD5 and CRC32 hash generator for Windows. The program has the ability to generate checksum for single file and verify its integrity by using verification files (.sha, .md5 and .sfv) generated by Total Commander, with support for UTF-8 verification files. It comes in a portable version also and hence, requires no installation.
IgorWare Hasher features:
- Calculates SHA-1, MD5 and CRC32 hash for single file or text
- Supports hash verification files (*.sha, *.md5, *.sfv) compatible with Total and Free Commander
- Drag and Drop file support
- Supports UTF8 verification files
- Automatically loads verification files when found
- Includes option to associate hasher with files in windows explorer
The ingenious program provides support for up to five hash algorithms including MD5, SHA-1, SHA-256, SHA-384, and SHA-512. Plus, it has the capability of calculating one or more hashes that exist in a single file, simultaneously.
The program includes a built-in famous virus scanner – Virus Total that lets a user know from the Virus Total database if a file is infected with some kind of virus. The program when downloaded, integrates into Windows Explorer. The Program contains no spyware, Adware and is 100% a freeware.
- Ability to calculate one or more hash values for a single file at once
- Ability to calculate hash values for multiple files and text string
- Supports following hash algorithms: CRC32, MD5, RIPEMD-160, SHA-1, SHA-256, SHA-384, SHA-512
- Supports hash file verification such as MHX, SFV, MD5Sum, etc.
- Unicode support
- Localizable UI
- Multiple language support
- Built-in virus checker
The tool is simple but very effective in its function. All a user need to do is browse for the file, or drag and drop them. MD5 and SHA1 hash values are then generated automatically in the corresponding fields. If you would like to verify the generated hash with a previous one, you can just paste it into the box and click Verify.
Unlike other programs which you may find as bloated, the tool just gives you the hash value with no frills thus, sufficient. MD5 & SHA-1 Checksum Utility is a complete freeware, portable and compatible with Windows XP, Vista and 7.
MD5 & SHA-1 Checksum Utility features:
- New and Simple Interface
- Support Drag and Drop for File
- Share hashes easily via Copy All button.
If you’d like to recommend any other, please do so in the comments below.