Base58Check encoding

The popular encoding of small and medium-sized checksums is base16, that is more compact than usual base10 and is human readable... For checksums resulting in hash digests bigger than ~100 bits, the base16 is too long: base58 is shorter and (when using good alphabet) preserves secure human readability. The most popular alphabet of base58 is the variant used in bitcoin address (see Bitcoin/address validation), so it is the "default base58 alphabet".

Write a program that takes a checksum (resultant hash digest) integer binary representation as argument, and converts (encode it) into base58 with the standard Bitcoin alphabet — which uses an alphabet of the characters 0 .. 9, A ..Z, a .. z, but without the four characters 0, O, I and l.

The reference algorithm is at the Bitcoin's Base58Check page.

Perl 6

<lang perl6>sub encode_Base58 ( Int $x ) {

   constant @codes = <
         1 2 3 4 5 6 7 8 9
       A B C D E F G H   J K L M N   P Q R S T U V W X Y Z
       a b c d e f g h i j k   m n o p q r s t u v w x y z
   >;

   return @codes[ $x.polymod( 58 xx * ) ].join.flip;

}

my @tests =

   25420294593250030202636073700053352635053786165627414518 => '6UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM',
   0x61                    => '2g',
   0x626262                => 'a3gV',
   0x636363                => 'aPEr',
   0x73696d706c792061206c6f6e6720737472696e67 => '2cFupjhnEsSn59qHXstmK2ffpLv2',
   0x516b6fcd0f            => 'ABnLTmg',
   0xbf4f89001e670274dd    => '3SEo3LWLoPntC',
   0x572e4794              => '3EFU7m',
   0xecac89cad93923c02321  => 'EJDM8drfXA6uyA',
   0x10c8511e              => 'Rt5zm',

use Test; for @tests {

   is encode_Base58(.key), .value, "{.key} encodes to {.value}";

} </lang>