开
SHA-256 Encryption
Tool Introduction
SHA-256 Encryption is an online SHA-256 hash tool that supports text string SHA-256 computation and file SHA-256 checksum verification. SHA-256 is the most widely used algorithm in the SHA-2 family, outputting a 256-bit (64 hexadecimal characters) hash value in both uppercase and lowercase formats. It is widely used in digital signatures, SSL/TLS certificates, blockchain, and other security scenarios.
How to Use
- Input text
Enter or paste the text you want to hash in the left input box.
- Compute hash
Click the "Compute SHA-256" button, and the right side will display the SHA-256 hash in both uppercase and lowercase formats.
- Copy result
Click the copy icon next to each result field to copy the hash value to your clipboard.
- File checksum
In the file checksum section at the bottom, click "Select File" and choose any file to automatically compute its SHA-256 hash for integrity verification.
Use Cases
- File integrity verification: After downloading software or files, compare their SHA-256 hash to verify that the files have not been tampered with or corrupted — the industry standard for file verification.
- Digital signatures and certificates: SHA-256 is the standard hash algorithm for current SSL/TLS certificates and digital signatures, supported by virtually all major browsers and operating systems.
- Blockchain and cryptocurrency: Bitcoin uses double SHA-256 (SHA-256d) as the core of its Proof-of-Work (PoW) algorithm, and it is the foundation for transaction IDs and block hashes.
- Password storage: SHA-256 is widely used for password hashing (typically combined with a salt), offering stronger security than MD5 and SHA-1. It is one of the recommended cryptographic hash algorithms today.
Key Advantages
- Free and no install
The tool is completely free and runs in your browser — no client software to download or install, compute hashes anytime, anywhere.
- Local and private
All SHA-256 operations (text hashing and file checksum) run locally in your browser; your content and files never leave your device, eliminating leakage risks.
- Upper and lower case output
Provides both uppercase and lowercase hexadecimal output formats to meet display needs across different systems and scenarios.
- Text and file support
Supports instant computation on input text strings as well as hash calculation for local files, covering both data checksum and integrity verification needs.
- Fast and stable
Built on a mature hashing implementation, it produces results quickly and stably regardless of text length or file size, without lag during prolonged use.
SHA-256 Algorithm Principles
SHA-256 (Secure Hash Algorithm 256-bit) belongs to the SHA-2 algorithm family, designed by the U.S. National Security Agency (NSA) and published by NIST in 2001 as the FIPS PUB 180-2 standard. SHA-256 is one of the most widely used cryptographic hash functions, with no effective collision attacks discovered to date.
The core process of SHA-256: ① Message padding — pad the message so its length ≡ 448 mod 512, then append a 64-bit representation of the original message length; ② Block processing — divide the padded message into 512-bit blocks; ③ Initialize 8 registers (a, b, c, d, e, f, g, h) using the fractional parts of the square roots of the first 8 primes; ④ 64 rounds — each round uses specific logical functions and 64 constants (fractional parts of the cube roots of the first 64 primes); ⑤ Output 256 bits — concatenate the final 8 register values to produce the 256-bit hash.
Key improvements of SHA-256 over SHA-1: output length increased from 160 to 256 bits, making collision attacks exponentially harder; the message schedule uses more complex σ functions for enhanced diffusion; 64 round constants increase the algorithm's non-linearity. SHA-256 currently achieves a good balance between security, performance, and compatibility.
SHA-256 vs. SHA-1 Detailed Comparison
The following table provides a detailed comparison of key characteristics between SHA-256 and SHA-1:
| Dimension | SHA-1 | SHA-256 |
|---|---|---|
| Output Bits | 160 | 256 |
| Hex Length | 40 | 64 |
| Rounds | 80 | 64 |
| Security | Broken (collision attack) | Secure (no effective attack found) |
| Typical Use Cases | Git VCS, legacy systems | Digital signatures, SSL/TLS, blockchain, password storage |
SHA-256 in Blockchain
SHA-256 is the core algorithm of Bitcoin and many cryptocurrencies. Bitcoin uses double SHA-256 (SHA-256d), meaning the data is hashed with SHA-256 once, and the result is hashed again. This design enhances security by preventing Length Extension Attacks.
In Bitcoin's Proof-of-Work (PoW) mechanism, miners must repeatedly try different Nonce values until the double SHA-256 of the block header is less than the target difficulty. This process involves trillions of SHA-256 calculations per second, fully demonstrating SHA-256's reliability in real-world large-scale applications.
FAQ
SHA-256 (Secure Hash Algorithm 256-bit) is a cryptographic hash function belonging to the SHA-2 algorithm family. It converts arbitrary-length input data into a fixed 256-bit (64 hexadecimal characters) output. SHA-256 is one-way and irreversible — the original data cannot be recovered from the hash value. It is currently one of the most widely used secure hash algorithms.
Key differences: ① Output length — SHA-256 outputs 256 bits (64 hex chars), SHA-1 outputs 160 bits (40 chars); SHA-256's security strength is approximately 2⁹⁶ times that of SHA-1; ② Security — SHA-1 has been proven vulnerable to collision attacks (SHAttered), while SHA-256 has no known effective attacks; ③ Structure — SHA-256 uses 8 × 32-bit registers and 64 rounds, SHA-1 uses 5 registers and 80 rounds; ④ Applications — SHA-256 is the current standard for SSL/TLS, digital signatures, and blockchain.
SHA-256 is currently considered secure. No effective collision or preimage attacks have been discovered to date. SHA-256's 256-bit output space is approximately 1.16×10⁷⁷, making brute-force attacks computationally infeasible. Quantum computers could theoretically reduce security strength to 128 bits via Grover's algorithm, but this remains far beyond current quantum computing capabilities. For the vast majority of applications, SHA-256 remains a very secure choice.
Yes. SHA-256's output length is always 256 bits (32 bytes). Regardless of the input data length (from 1 byte to several GB), SHA-256 always produces a 64-character hexadecimal hash value. This is a common property of all cryptographic hash functions — fixed output length independent of input length.
No. All SHA-256 operations (text hashing and file checksum) run entirely in your browser using the CryptoJS library on the client side. Your text content and file data never leave your device.
SHA-256 should be used in any scenario requiring security. MD5 and SHA-1 have been proven vulnerable to collision attacks and should not be used for security-sensitive scenarios. SHA-256 is suitable for: ① Digital signatures — the standard signing algorithm for SSL/TLS certificates; ② File integrity verification — providing SHA-256 checksums when releasing software; ③ Password storage — hashing passwords with a salt; ④ Blockchain — the core algorithm of Bitcoin and other cryptocurrencies. Only consider SHA-1 or MD5 when security requirements are low and compatibility with legacy systems is needed.
Both text and files are supported. In text mode you can type any characters (Chinese, English, symbols, emoji, etc.) directly into the input box; in file mode you can select any local file (no type or extension restriction). Both modes run locally in your browser without uploading.
Speed grows slightly with file size, but remains fast overall. SHA-256 reads files in a streaming manner, and files of several hundred MB usually finish within seconds. Computation runs locally, consuming no server resources and no bandwidth.
No registration is required for basic use. The tool provides you with free daily usage credits; light everyday needs are covered at zero cost. For higher quotas or more frequent use, upgrade to a membership to unlock more benefits.
Yes. The page is responsive and works in mobile browsers too — you can enter text, upload files, and compute SHA-256, with the layout adapting automatically to your screen.
This is the deterministic nature of hash functions. SHA-256 is a deterministic cryptographic hash function: identical input always yields identical output. As long as the text content (including case, spaces, and line breaks) is exactly the same, the hash never changes, which is why it can be used to verify whether content was altered.
Choose SHA-256 whenever security matters. MD5 outputs only 128 bits and is proven vulnerable to collisions, suitable only for non-security file quick comparison; SHA-256 has a longer output and high security, and is the recommended choice for digital signatures, certificates, password storage, and blockchain.
Content last updated：2026-07-15
DES Encryption
Online DES/2DES/3DES encryption and decryption tool, supporting all encryption modes and padding methods. Fully processed locally in the browser for security and efficiency.
AES Encryption
Online AES encryption and decryption tool, supporting AES-128/192/256, covering all encryption modes and padding methods, secure, efficient, and easy to operate.
3DES Encryption
Online 3DES encryption/decryption tool, supporting all encryption modes and padding methods, fully processed locally in the browser to ensure data security.
RC4 Encryption
Online RC4 stream cipher encryption/decryption tool, supports multiple key lengths, one-click encryption and decryption, all operations are completed locally in the browser to ensure data security.
Rabbit Encryption
Online Rabbit stream cipher encryption/decryption tool, using a high-speed symmetric encryption algorithm, supporting multiple key lengths. All operations are performed locally in the browser to ensure data security.
RC2 Encryption
Online RC2 encryption and decryption tool, supporting ECB/CBC modes, variable key length and effective key bits, all processed locally in the browser to ensure data security.
IDEA Encryption
Online IDEA International Data Encryption Algorithm Tool, supporting multiple encryption modes including ECB/CBC/CFB/OFB/CTR. All operations are performed locally in the browser to ensure data security.
Blowfish Encryption
Online Blowfish encryption/decryption tool supporting 128/192/256/448-bit variable keys, ECB/CBC/CFB/OFB modes, and multiple padding methods. All operations are performed locally in the browser to ensure data security.
CAST Encryption
CAST-128 (CAST5) online encryption and decryption tool, supporting multiple encryption modes such as ECB/CBC/CFB/OFB, flexible padding methods, and output encoding. All operations are performed locally in the browser, ensuring security and efficiency.
SM4 National Encryption
Online SM4 National Symmetric Encryption and Decryption Tool, supporting five working modes: ECB/CBC/CFB/OFB/CTR, and multiple padding methods. All operations are performed locally in the browser to ensure data security.
RSA Encryption and Decryption
Online RSA asymmetric encryption and decryption tool, supporting key pair generation, public key encryption and private key decryption, private key signing and public key verification. All operations are performed locally in the browser to ensure data security.
MD5 Encryption
Online MD5 hash encryption tool, supporting 16-bit/32-bit output, case switching, and file MD5 verification. All operations are completed locally in the browser, ensuring security and efficiency.
MD2 Encryption
MD2 Encryption Tool: Generate 32-bit MD2 hash values online, supporting uppercase/lowercase output and file verification.
SHA-1 Encryption
Online SHA-1 hash calculation tool for efficient text encryption and file integrity verification.
SHA-384 Encryption
Online SHA-384 hash calculation tool for fast text encryption and file integrity verification.
SHA-512 Encryption
Online SHA-512 hash calculation tool, supporting text encryption and file integrity verification, quickly generating secure hash values.
SM3 National Encryption
Online SM3 National Hash Encryption Tool, supports text hash calculation and file verification, outputs a 256-bit hash value, compliant with GM/T 0004-2012 national standard.
Base64 Encode/Decode
Online Base64 encode/decode tool, supporting text Base64 encoding and decoding, all done locally in the browser, safe and efficient.
URL Encode/Decode
Online URL encoding and decoding tool, supports intelligent encoding and decoding of URL parameters, automatically identifies URL structure, processes only the parameter part, completes entirely in the browser locally, safe and efficient.
UTF-8 Encode/Decode
Online UTF-8 encoding/decoding tool, supporting conversion between text and UTF-8 hexadecimal bytes. All processing is done locally in the browser, ensuring data security.
