Seems like there is a typo in docs, look,

```
block_length → Integer
Returns the block length of the digest in bytes.
Digest::SHA256.new.digest_length * 8
# => 512
Digest::SHA384.new.digest_length * 8
# => 1024
Digest::SHA512.new.digest_length * 8
# => 1024
digest_length → Integer
Returns the length of the hash value of the digest
in bytes.
Digest::SHA256.new.digest_length * 8
# => 256
Digest::SHA384.new.digest_length * 8
# => 384
Digest::SHA512.new.digest_length * 8
# => 512
```

Both are using `digest_length`

in
examples.

But instead it should be,

```
block_length → Integer
Returns the block length of the digest in bytes.
Digest::SHA256.new.block_length * 8
# => 512
Digest::SHA384.new.block_length * 8
# => 1024
Digest::SHA512.new.block_length * 8
# => 1024
digest_length → Integer
Returns the length of the hash value of the digest
in bytes.
Digest::SHA256.new.digest_length * 8
# => 256
Digest::SHA384.new.digest_length * 8
# => 384
Digest::SHA512.new.digest_length * 8
# => 512
```