Created
September 2, 2015 00:34
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Merkle tree implementation in Racket
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#lang racket | |
(require openssl/sha1) | |
(struct node (value left right) #:transparent) | |
(define (hash s) | |
(sha1 (open-input-string s))) | |
(define (build-foundation l [hash hash]) | |
(let loop ([l l]) | |
(if (null? l) | |
null | |
(if (= 1 (length l)) | |
(list (node (hash (first l)) null null)) | |
(let ([vals (take l 2)]) | |
(cons (node (hash (string-append (first vals) (second vals))) | |
(node (hash (first vals)) null null) | |
(node (hash (second vals)) null null)) | |
(loop (drop l 2)))))))) | |
(define (build-next-node a b) | |
(node (hash (string-append (node-value a) (node-value b))) | |
a | |
b)) | |
(define (merkle-tree l [hash hash]) | |
(define (aux l) | |
(if (= 1 (length l)) | |
l | |
(aux (let loop ([l l]) | |
(if (null? l) | |
null | |
(if (= 1 (length l)) | |
(list (node (hash (node-value (first l))) null null)) | |
(let ([vals (take l 2)]) | |
(cons (build-next-node (first vals) (second vals)) (loop (drop l 2)))))))))) | |
(first (aux (build-foundation l hash)))) | |
(module+ test | |
(define test-1 (build-list 10000 (lambda (i) (number->string i)))) | |
(merkle-tree test-1)) | |
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