Build the Root

Root Hash

The root hashes the two parents into one check value.

highlighted = computed this step

The root hashes the two parents

The root is computed from parent AB=0x65 and parent CD=0xa9.

H(0x65∥0xa9)H(0x65\Vert 0xa9)
Root hashA toy Merkle tree is recomputed from four one-byte chunks.Root hash - original root 0eroot 0eoriginal rootAB 65pair hashA aaleaf hashB bbleaf hashCD a9pair hashC ccleaf hashD ddleaf hash

The parent bytes wrap again

0x65 plus 0xa9 gives 0x10e, so the displayed root is 0x0e.

H(0x65∥0xa9)=0x0eH(0x65\Vert 0xa9)=0x0e
Root hashA toy Merkle tree is recomputed from four one-byte chunks.Root hash - original root 0eroot 0eoriginal rootAB 65pair hashA aaleaf hashB bbleaf hashCD a9pair hashC ccleaf hashD ddleaf hash

The root is the compact check value

The original tree root is 0x0e. A verifier can recompute it from the chunks.

root=0x0e\text{root}=0x0e
Root hashA toy Merkle tree is recomputed from four one-byte chunks.Root hash - original root 0eroot 0eoriginal rootAB 65pair hashA aaleaf hashB bbleaf hashCD a9pair hashC ccleaf hashD ddleaf hash

Summary

The root is small here because the hash is a toy one-byte rule.

root=0x0e\text{root}=0x0e
Root hashA toy Merkle tree is recomputed from four one-byte chunks.Root hash - original root 0eroot 0eoriginal rootAB 65pair hashA aaleaf hashB bbleaf hashCD a9pair hashC ccleaf hashD ddleaf hash