---
name: "Crypt::Misc"
section: "3pm"
platform: "linux"
package: "perl-cryptx"
version: "0.091-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Crypt::Misc"
---

# Crypt::Misc(3pm)

miscellaneous functions related to (or used by) CryptX

## NAME

Crypt::Misc - miscellaneous functions related to (or used by) CryptX

## SYNOPSIS

```
 use Crypt::Misc ':all';
 my $rawbytes = 'hello world';
 my $filename = 'sample.bin';
 my $pem_data = "-----BEGIN PUBLIC KEY-----\n...\n-----END PUBLIC KEY-----\n";
 my $str1 = 'same';
 my $str2 = 'same';
 # Base64 and Base64 URL-safe functions
 my $base64    = encode_b64($rawbytes);
 my $rawbytes2 = decode_b64($base64);
 my $base64url = encode_b64u($rawbytes);
 my $rawbytes3 = decode_b64u($base64url);
 # read/write file
 my $rawdata = read_rawfile($filename);
 write_rawfile($filename, $rawdata);
 # convert PEM/DER
 my $der_data = pem_to_der($pem_data);
 my $pem_data2 = der_to_pem($der_data, "PUBLIC KEY");
 # others
 die "mismatch" unless slow_eq($str1, $str2);
```

## DESCRIPTION

This module contains a collection of helper functions related to CryptX, but it does not implement cryptography itself.

Most of them are also available in other Perl modules. If you already use CryptX, these helpers can reduce extra dependencies.

## EXPORT

Nothing is exported by default.

You can export selected functions:

```
  use Crypt::Misc qw(read_rawfile write_rawfile slow_eq);
```

Or all of them at once:

```
  use Crypt::Misc ':all';
```

## FUNCTIONS

All encoding functions (`"encode_b64"`, `"encode_b58b"`, etc.) accept a binary string and return an ASCII string. All decoding functions (`"decode_b64"`, `"decode_b58b"`, etc.) accept an ASCII string and return a binary string, or `"undef"` if the input is malformed.

An empty string is considered valid input and decodes to an empty string. `"undef"` is considered invalid input and results in `"undef"`. Non-empty input with no actual payload, such as whitespace-only or padding-only input, is also considered malformed and results in `"undef"`.

The Base64 decoders `"decode_b64"` and `"decode_b64u"` also accept otherwise valid payload with embedded whitespace. The other decoder families in this module do not; for them, embedded whitespace is treated as malformed input.

### read\_rawfile

*Since: CryptX-0.029*

```
 $rawdata = read_rawfile($filename);
```

Reads file `$filename` into a scalar as binary data, without decoding or transformation.

### write\_rawfile

*Since: CryptX-0.029*

```
 write_rawfile($filename, $rawdata);
```

Writes `$rawdata` to file `$filename` as binary data.

### slow\_eq

*Since: CryptX-0.029*

```
 if (slow_eq($data1, $data2)) { ... }
```

Compares two strings in constant time to reduce timing side channels. Returns `1` if the strings are equal, `0` if they differ, or `"undef"` if either argument is `"undef"`.

### pem\_to\_der

*Since: CryptX-0.029*

```
  $der_data = pem_to_der($pem_data);
  #or
  $der_data = pem_to_der($pem_data, $password);
```

Converts PEM to DER. Also supports password-protected PEM data. Returns `"undef"` if `$pem_data` cannot be parsed (no valid PEM block found) or if the `"BEGIN"` / `"END"` labels do not match. Croaks if the PEM is encrypted but no `$password` is provided. If an encrypted PEM is supplied with the wrong password, decryption is expected to croak from the underlying cipher/padding layer.

### der\_to\_pem

*Since: CryptX-0.029*

```
  $pem_data = der_to_pem($der_data, $header_name);
  #or
  $pem_data = der_to_pem($der_data, $header_name, $password);
  #or
  $pem_data = der_to_pem($der_data, $header_name, $password, $cipher_name);
  # $header_name e.g. "PUBLIC KEY", "RSA PRIVATE KEY" ...
  # $cipher_name e.g. "DES-EDE3-CBC", "AES-256-CBC" (DEFAULT) ...
```

Converts DER to PEM. Returns an ASCII PEM string. Also supports password-protected PEM data. Any defined `$password`, including false-like values like `''` or `'0'`, enables PEM encryption.

**Security note**: do not use ECB-based ciphers (e.g. `"AES-256-ECB"`) for PEM encryption - ECB encrypts each block independently, leaking plaintext structure. Use the default `"AES-256-CBC"` or another chaining mode (CBC, CFB, OFB).

**Security note**: the traditional PEM encryption format uses a single-iteration MD5-based key derivation which is weak against brute-force. For new applications, prefer PKCS#8 encrypted keys (e.g. via "export\_key\_pem" in Crypt::PK::RSA) or an independent encryption layer.

### random\_v4uuid

*Since: CryptX-0.031*

```
 my $uuid = random_v4uuid();
```

Returns a cryptographically strong version 4 random UUID: `"xxxxxxxx-xxxx-4xxx-Yxxx-xxxxxxxxxxxx"` where `"x"` is any hexadecimal digit and `"Y"` is one of 8, 9, A, B (1000, 1001, 1010, 1011) e.g. `"f47ac10b-58cc-4372-a567-0e02b2c3d479"`.

### is\_v4uuid

*Since: CryptX-0.031*

```
  if (is_v4uuid($uuid)) {
    ...
  }
```

Checks whether the given `$uuid` string matches version 4 UUID format with a relaxed variant policy. The variant nibble may be one of `0`, `8`, `9`, `"A"`, or `"B"`. Returns `0` (mismatch) or `1` (match).

### random\_v7uuid

*Since: CryptX-0.088*

```
 my $uuid = random_v7uuid();
```

Returns a cryptographically strong version 7 time-ordered UUID: `"xxxxxxxx-xxxx-7xxx-Yxxx-xxxxxxxxxxxx"` where the first 48 bits encode the current Unix time in milliseconds (making UUIDs sortable by generation time), followed by random bits. Ordering is therefore coarse at millisecond granularity only; UUIDs generated within the same millisecond are not guaranteed to be lexicographically monotonic. `"Y"` is one of 8, 9, A, B (RFC 9562 variant).

### is\_uuid

*Since: CryptX-0.088*

```
  if (is_uuid($uuid)) {
    ...
  }
```

Checks whether `$uuid` is a validly formatted UUID (any version) in the standard `"xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"` form with a relaxed variant policy. The variant nibble may be one of `0`, `8`, `9`, `"A"`, or `"B"`. Returns `1` (match) or `0` (mismatch). For a version-specific check see "is\_v4uuid".

### increment\_octets\_le

*Since: CryptX-0.048*

```
 $octets = increment_octets_le($octets);
```

Treats `$octets` as a little-endian big number and returns the incremented value.

### increment\_octets\_be

*Since: CryptX-0.048*

```
 $octets = increment_octets_be($octets);
```

Treats `$octets` as a big-endian big number and returns the incremented value.

### encode\_b64

*Since: CryptX-0.029*

```
 $base64string = encode_b64($rawdata);
```

Encodes `$rawdata` as a Base64 string. No line endings are added.

### decode\_b64

*Since: CryptX-0.029*

```
 $rawdata = decode_b64($base64string);
```

Decodes a Base64 string.

### encode\_b64u

*Since: CryptX-0.029*

```
 $base64url_string = encode_b64u($rawdata);
```

Encodes `$rawdata` as a Base64 URL-safe string. No line endings are added.

### decode\_b64u

*Since: CryptX-0.029*

```
 $rawdata = decode_b64u($base64url_string);
```

Decodes a Base64 URL-safe string.

### encode\_b32r

*Since: CryptX-0.049*

```
 $string = encode_b32r($rawdata);
```

Encode bytes into Base32 (rfc4648 alphabet) string, without "=" padding.

### decode\_b32r

*Since: CryptX-0.049*

```
 $rawdata = decode_b32r($string);
```

Decode a Base32 (rfc4648 alphabet) string into bytes.

### encode\_b32b

*Since: CryptX-0.049*

```
 $string = encode_b32b($rawdata);
```

Encode bytes into Base32 (base32hex alphabet) string, without "=" padding.

### decode\_b32b

*Since: CryptX-0.049*

```
 $rawdata = decode_b32b($string);
```

Decode a Base32 (base32hex alphabet) string into bytes.

### encode\_b32z

*Since: CryptX-0.049*

```
 $string = encode_b32z($rawdata);
```

Encode bytes into Base32 (zbase32 alphabet) string.

### decode\_b32z

*Since: CryptX-0.049*

```
 $rawdata = decode_b32z($string);
```

Decode a Base32 (zbase32 alphabet) string into bytes.

### encode\_b32c

*Since: CryptX-0.049*

```
 $string = encode_b32c($rawdata);
```

Encode bytes into Base32 (crockford alphabet) string.

### decode\_b32c

*Since: CryptX-0.049*

```
 $rawdata = decode_b32c($string);
```

Decode a Base32 (crockford alphabet) string into bytes.

### encode\_b58b

*Since: CryptX-0.049*

```
 $string = encode_b58b($rawdata);
```

Encode bytes into Base58 (Bitcoin alphabet) string.

### decode\_b58b

*Since: CryptX-0.049*

```
 $rawdata = decode_b58b($string);
```

Decode a Base58 (Bitcoin alphabet) string into bytes.

### encode\_b58f

*Since: CryptX-0.049*

```
 $string = encode_b58f($rawdata);
```

Encode bytes into Base58 (Flickr alphabet) string.

### decode\_b58f

*Since: CryptX-0.049*

```
 $rawdata = decode_b58f($string);
```

Decode a Base58 (Flickr alphabet) string into bytes.

### encode\_b58r

*Since: CryptX-0.049*

```
 $string = encode_b58r($rawdata);
```

Encode bytes into Base58 (Ripple alphabet) string.

### decode\_b58r

*Since: CryptX-0.049*

```
 $rawdata = decode_b58r($string);
```

Decode a Base58 (Ripple alphabet) string into bytes.

### encode\_b58t

*Since: CryptX-0.049*

```
 $string = encode_b58t($rawdata);
```

Encode bytes into Base58 (Tipple alphabet) string.

### decode\_b58t

*Since: CryptX-0.049*

```
 $rawdata = decode_b58t($string);
```

Decode a Base58 (Tipple alphabet) string into bytes.

### encode\_b58s

*Since: CryptX-0.049*

```
 $string = encode_b58s($rawdata);
```

Encode bytes into Base58 (Stellar alphabet) string.

### decode\_b58s

*Since: CryptX-0.049*

```
 $rawdata = decode_b58s($string);
```

Decode a Base58 (Stellar alphabet) string into bytes.

## SEE ALSO

- •

  CryptX
