SHA256 Hashes

crypto/sha256 for one-shot and streaming SHA-256 hashing, hex encoding the digest, and when not to use SHA256 for passwords.

The crypto/sha256 package computes a fixed 32-byte digest. Use sha256.Sum256 for small byte slices and hex encoding when you need a printable checksum.

The returned digest is an array. Slice it when passing it to functions such as hex.EncodeToString.

package main
 
import (
    "crypto/sha256"
    "encoding/hex"
    "fmt"
)
 
func main() {
    digest := sha256.Sum256([]byte("hello"))
    fmt.Println(hex.EncodeToString(digest[:]))
}

In production

For large input, stream data through sha256.New with io.Copy instead of loading it all into memory. SHA-256 is suitable for checksums and content hashes, but not password storage; use a dedicated password-hashing function such as bcrypt or Argon2id. Use hmac.Equal when verifying message authentication codes.

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