Tcl Requires Chilkat v11.6.0+

Hash a Password with Argon2 (Defaults)

Demonstrates Crypt2.Argon2HashPassword, which hashes a password with Argon2 and returns a PHC-format string. Passing an empty options string uses all defaults, including a random salt.

Background. Argon2 (RFC 9106) is a memory-hard function that is deliberately expensive in CPU time and memory, which is what makes brute-forcing the password space costly. The argon2id variant is recommended unless there is a specific reason to choose argon2i or argon2d. The returned PHC string records the variant, version, cost parameters, salt, and hash — everything needed to verify the password later. Store the whole string.

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Tcl


load ./chilkat.dll

set crypt [new_CkCrypt2]

#  The password should come from a secure source rather than being hard-coded.
set password "correct horse battery staple"

#  Hash the password using all defaults by passing an empty options string.  The defaults are
#  Argon2id, version 19, 3 iterations, 64 MB of memory, 1 lane, a 32-byte hash, and a 16-byte random
#  salt.  A random salt is generated automatically, which is what should normally happen.
set phcHash [CkCrypt2_argon2HashPassword $crypt $password ""]
if {[CkCrypt2_get_LastMethodSuccess $crypt] == 0} then {
    puts [CkCrypt2_lastErrorText $crypt]
    delete_CkCrypt2 $crypt
    exit
}

#  The returned PHC-format string records the variant, version, cost parameters, salt, and hash --
#  everything needed to verify the password later.  Store the whole string.
puts "$phcHash"

delete_CkCrypt2 $crypt