Hi Norbert and guys on the list, I finally made the suggestion Norbert gave me (see here: https://lists.pharo.org/empathy/thread/PG7CCEBGJOI4SNGO6GNQPCLP47EXWFAX?hash... ) working. There was something to tune in: 1) The SSL binding here https://github.com/PierceNg/OpenSSL-Pharo that's working on Pharo 10 is the pharo9 one. This one:  Metacello new  baseline: 'OpenSSL';  repository: 'github://PierceNg/OpenSSL-Pharo:openssl_1_1_pharo9/src-st';  load  the previous one (github://PierceNg/OpenSSL-Pharo:openssl_1_1/src-st) does not work with Pharo 10, it gives a DNU on LcLibCrypto>>moduleName. 2) The code Norbert suggested (https://lists.pharo.org/empathy/thread/PG7CCEBGJOI4SNGO6GNQPCLP47EXWFAX?hash...) should be implemented in a subclass of LcLibCrypto LcLibCrypto subclass: #MyCrypto instanceVariableNames: '' classVariableNames: '' package: 'MyPackage' 3) Call the method pbkdf2Password: aPlainPassword salt: aSalt iterations: someIterations keySize: aSize using uniqueInstance, i.e. MyCrypto uniqueInstance pbkdf2Password: aPlainPassword salt: aSalt iterations: someIterations keySize: aSize HTH CheersDavode