Generating a SHA-256 hash from the Linux command line

Question

I know the string "03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd" generates the SHA-256 hash 4c0b2d2f119a09b607cb273a745b2b0430d5192e0c4e536f932be5d1a6be5883 using https://privatekeys.pw/calc

However the command line

┌──(root㉿localhost)-[/home/kali] └─# echo "03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd" | sha256sum 92dbdf5d8231512f44fff4544d41b334ff8042db23e4dee454d4b0b61121f3ff - ┌──(root㉿localhost)-[/home/kali] └─# echo -n "03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd" | sha256sum 0f5b284caf3ab192b20f849b7b53d5877b83cae8b7bc617dc34104e6688ed45e - ┌──(root㉿localhost)-[/home/kali] └─# sha256sum <<< 03a34b99f22c790c4e36b2b3c2c35a36db06226e41c692fc82b8b56ac1c540c5bd 92dbdf5d8231512f44fff4544d41b334ff8042db23e4dee454d4b0b61121f3ff - ┌──(root㉿localhost)-[/home/kali] └─# sha256sum hash 92dbdf5d8231512f44fff4544d41b334ff8042db23e4dee454d4b0b61121f3ff hash 

Generates a different hash. What am I missing?

Answer 1

I know the string "03a3... " generates the SHA-256 hash 4c0b... using https://privatekeys.pw/calc

The string does not result in this hash. What you likely mean is not to treat the string as it is, but as hex-encoded binary data. This means you need to convert the hex string to binary first before doing the hash, like this:

echo 03a3... | xxd -r -p - | sha256sum