Unsupported hash type ripemd160 with hashlib in Python

Question

After a thorough search, I have not found a complete explanation and solution to this very common problem on the entire web. All scripts that need to encode with hashlib give me error:

Python 3.10

import hashlib
h = hashlib.new('ripemd160')

return:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.10/hashlib.py", line 166, in __hash_new
    return __get_builtin_constructor(name)(data)
  File "/usr/lib/python3.10/hashlib.py", line 123, in __get_builtin_constructor
    raise ValueError('unsupported hash type ' + name)
ValueError: unsupported hash type ripemd160

I already tried to check if that hash exists in the library, and if I have it:

print(hashlib.algorithms_available): {'md5', 'sm3', 'sha3_512', 'sha384', 'sha256', 'sha1', 'shake_128', 'sha224', 'sha512_224', 'sha512_256', 'blake2b', 'ripemd160', 'md5-sha1', 'sha512', 'sha3_256', 'shake_256', 'sha3_384', 'whirlpool', 'md4', 'blake2s', 'sha3_224'}

I am having this problem in a vps with linux, but in my pc I use Windows and I don't have this problem.

I sincerely appreciate any help or suggestion.

Any others missing? Could you run this and share your output? — Kelly Bundy
– Kelly Bundy, Commented May 27, 2022 at 18:26

streamofstars · Accepted Answer · 2022-06-05 15:55:43Z

30

Hashlib uses OpenSSL for ripemd160 and apparently OpenSSL disabled some older crypto algos around version 3.0 in November 2021. All the functions are still there but require manual enabling. See issue 16994 of OpenSSL github project for details.

To quickly enable it, find the directory that holds your OpenSSL config file or a symlink to it, by running the below command:

openssl version -d

You can now go to the directory and edit the config file (it may be necessary to use sudo):

nano openssl.cnf

Make sure that the config file contains following lines:

openssl_conf = openssl_init

[openssl_init]
providers = provider_sect

[provider_sect]
default = default_sect
legacy = legacy_sect

[default_sect]
activate = 1

[legacy_sect]
activate = 1

Tested on: OpenSSL 3.0.2, Python 3.10.4, Linux Ubuntu 22.04 LTS aarch64, I have no access to other platforms at the moment.

answered Jun 5, 2022 at 15:55

streamofstars

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3 Comments

caiofior Over a year ago

Well done. I had solved in this way an error in Zeronet.

Arun Panneerselvam Over a year ago

its great. the release notes bold sections said 'Added RIPEMD160 to the default provider' in nov'22 and in Dec'21 it says its moved and 'All of the low-level MD2, MD4, MD5, MDC2, RIPEMD160, SHA1, SHA224, SHA256, SHA384, SHA512 and Whirlpool digest functions have been deprecated.' - clearly deprecated.

sibnick Over a year ago

Actually you do not need sudo. You can run python with env variable: OPENSSL_CONF=openssl.cnf python3 some_script.py

Uwe Kleine-König · Accepted Answer · 2025-05-19 14:13:34Z

0

With openssl 3.5.0-1 and python3.13.2 (as provided by Debian trixie), I have:

$ python3
Python 3.13.2 (main, Mar 29 2025, 10:04:43) [GCC 14.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import hashlib
>>> hashlib.new('ripemd160', b'lala').hexdigest()
'3e72844027d4e2aa163c0ef7faea8ff9d831bae2'

and it works just fine using openssl, too:

$ echo -n lala | openssl ripemd160
RIPEMD-160(stdin)= 3e72844027d4e2aa163c0ef7faea8ff9d831bae2

answered May 19, 2025 at 14:13

Uwe Kleine-König

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