Challenge 16 Problem 2 plus blog by Jaldhar H. Vyas.

3 files changed, 71 insertions, 0 deletions

diff --git a/challenge-016/jaldhar-h-vyas/blog.txt b/challenge-016/jaldhar-h-vyas/blog.txt
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+++ b/challenge-016/jaldhar-h-vyas/blog.txt
@@ -0,0 +1 @@
+https://www.braincells.com/perl/2023/05/perl_weekly_challenge_week_16.html
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diff --git a/challenge-016/jaldhar-h-vyas/perl5/ch-2.pl b/challenge-016/jaldhar-h-vyas/perl5/ch-2.pl
new file mode 100755
index 0000000000..f83ec5c488
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+++ b/challenge-016/jaldhar-h-vyas/perl5/ch-2.pl
@@ -0,0 +1,37 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use 5.010;
+use Digest::SHA qw/ sha256 /;
+
+sub fromBase58 {
+    my ($address) = @_;
+
+    my %digits;
+    @digits{( 1 .. 9, 'A' .. 'H', 'J' .. 'N', 'P' .. 'Z', 'a' .. 'k',
+    'm' .. 'z')} = 0 .. 57;
+
+    my @result;
+
+    for my $c ( map { $digits{$_} } split //, $address ) {
+        for (my $j = 25; $j--; ) {
+            $c += 58 * ($result[$j] // 0);
+            $result[$j] = $c % 256;
+            $c /= 256;
+        }
+    }
+
+    return @result;
+}
+ 
+sub isValidBitcoinAddress {
+    my ($address) = @_;
+
+    my @bytes = fromBase58($address);
+    my $decoded = sha256(sha256 pack 'C*', @bytes[0..20]);
+    my $checksum = pack 'C*', @bytes[21..24];
+
+    return $checksum eq substr $decoded, 0, 4;
+}
+
+say  isValidBitcoinAddress(shift) ? q{} : 'in', 'valid';
diff --git a/challenge-016/jaldhar-h-vyas/perl6/ch-2.p6 b/challenge-016/jaldhar-h-vyas/perl6/ch-2.p6
new file mode 100755
index 0000000000..8a10ee17f7
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+++ b/challenge-016/jaldhar-h-vyas/perl6/ch-2.p6
@@ -0,0 +1,33 @@
+#!/usr/bin/perl6
+use Digest::SHA256::Native;
+
+sub fromBase58($address) {
+    my %digits = ( 1 .. 9, 'A' .. 'H', 'J' .. 'N', 'P' .. 'Z', 'a' .. 'k',
+        'm' .. 'z').flat Z=> 0 .. 57;
+
+    my @result;
+
+    for $address.comb.map({ %digits{$_} }) -> $digit {
+        my $c = $digit;
+        for 24 ... 0 -> $j  {
+            $c += (58 * (@result[$j] // 0));
+            @result[$j] = $c % 256;
+            $c div= 256;
+        }
+    }
+
+    return @result;
+}
+
+sub isValidBitcoinAddress($address) {
+    my @bytes = fromBase58($address);
+    my $decoded = sha256(sha256(Blob.new(@bytes[0..20])));
+    my $checksum = Blob.new(@bytes[21..24]);
+    return $checksum eqv $decoded.subbuf(0, 4);
+}
+
+sub MAIN (
+    $address    #= a bitcoin address to validate.
+) {
+    say isValidBitcoinAddress($address) ?? q{}  !! 'in', 'valid';
+}
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