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SHA-1

Tool to decrypt/encrypt with SHA1. SHA-1 hash is a footprint of 40 characters (hexadecimal) which is made to identify the initial data and guarantee its integrity, that is useful in cryptography.

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Tag(s) : Modern Cryptography, Informatics

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# SHA-1

## SHA1 Encoder

Tool to decrypt/encrypt with SHA1. SHA-1 hash is a footprint of 40 characters (hexadecimal) which is made to identify the initial data and guarantee its integrity, that is useful in cryptography.

### How to encrypt using Secure Hash Algorithm (SHA-1) ?

Encryption calculates a numeric footprint of 40 hexadecimal characters. The algorithm uses non linear functions, here are the 3 main ones:

$$C(x,y,z) = (x \wedge y) \vee (\lnot x \wedge z) \\ P(x,y,z) = x \oplus y \oplus z \\ M(x,y,z) = (x \wedge y) \vee (x \wedge z)$$

With $$x,y,z$$ portions of string to encode or fixed values among 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0...

Example: dCode is crypted with the footprint 15fc6eed5ed024bfb86c4130f998dde437f528ee.

### How to decrypt a SHA-1 hash?

As encryption is a hashing based on nonlinear functions, there is no decryption method. This means that to retrieve the password corresponding to a sha-1 hash, there is no choice but to try all possible passwords!

Technically, this operation would take several thousand years, even on the most powerful computers in the world. However, the list of passwords used in real life is more restricted, and it becomes possible to precalculate the most likely fingerprints.

dCode uses its word databases (10 million potential passwords) to speed up this processing. However, if the password is rare, it will not be found.

### How to recognize SHA-1 ciphertext?

The hash is composed of 40 hexadecimal characters among 0123456789abcdef.

### What are the variants of the SHA-1 cipher?

The database search can be complicated by inserting salt to the word (a prefix or a suffix, or both). Indeed, if it is already difficult but possible to precalculate the fingerprints of all the words, it becomes even more difficult to precalculate with all possible prefixes and suffixes.

Example: SHA1(dCode) = 15fc6eed5ed024bfb86c4130f998dde437f528ee but SHA1(dCodeSUFFIX) = 9b63fcb31388acee8879018244a3d107033890f1

Another (not recommended) variant is DOUBLE SHA1, that consists in applying SHA1 twice.

### What is a rainbow table?

A rainbow table is a database of words with all the hashs pre-computed and stored in order to accelerate and be able to parallelize the calculations of fingerprints.

### What does SHA1 means?

SHA1 stands for Secure Hash Algorithm

### When SHA1 have been invented ?

By the National Security Agency in 1995

## Source code

dCode retains ownership of the source code of the script SHA-1 online. Except explicit open source licence (indicated Creative Commons / free), any algorithm, applet, snippet, software (converter, solver, encryption / decryption, encoding / decoding, ciphering / deciphering, translator), or any function (convert, solve, decrypt, encrypt, decipher, cipher, decode, code, translate) written in any informatic langauge (PHP, Java, C#, Python, Javascript, Matlab, etc.) which dCode owns rights will not be given for free. To download the online SHA-1 script for offline use on PC, iPhone or Android, ask for price quote on contact page !