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SHA-1

Deprecated

SHA-1 (Secure Hash Algorithm 1) produces a 160-bit hash value. Once the standard for digital signatures and certificates, it was deprecated after Google demonstrated a practical collision attack (SHAttered) in 2017.

What is SHA-1?

SHA-1 is a deprecated cryptographic hash algorithm that produces a 160 bits (40 hex characters) output. SHA-1 (Secure Hash Algorithm 1) produces a 160-bit hash value. Once the standard for digital signatures and certificates, it was deprecated after Google demonstrated a practical collision attack (SHAttered) in 2017. It is classified as very fast in performance and commonly used for git commit hashing (legacy, git is transitioning to sha-256) and legacy system compatibility where upgrading is not possible.

Output Length

160 bits (40 hex characters)

Speed

Very Fast

Security

Deprecated

Performance

Very fast — slightly slower than MD5 but still processes GB/s. Not suitable for password hashing.

Use Cases

Example Hash

Input:

Hello, World!

SHA-1 Output:

0a0a9f2a6772942557ab5355d76af442f8f65e01

Try SHA-1 Hash Generator

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Related Algorithms

MD5 Deprecated
128 bits (32 hex characters)
SHA-256 Recommended
256 bits (64 hex characters)
SHA-512 Recommended
512 bits (128 hex characters)

Related Reading

SHA-256 vs SHA-512 vs MD5: Hash Algorithm Comparison → How to Create a Strong Password in 2026 → What Is JWT and How It Works →