The hash format indicates it's using PHPass: http://cvsweb.openwall.com/cgi/cvsweb.cgi/projects/phpass/Pa... which is based on MD5, but with the log of the number of rounds indicated by the first character after the $P$ prefix. In the forum example, it's "B" which is 11 making it 2^11 rounds. The remainder is an 8 character salt plus checksum. PHPass is authored by "Solar Designer" or Alexander Peslyak, also the author of John the Ripper and respected in the security community: http://en.wikipedia.org/wiki/Alexander_Peslyak so is likely pretty solid.
Solar Designer is great. Here's what his PHPass page says:
The preferred (most secure) hashing method supported by phpass is the OpenBSD-style Blowfish-based bcrypt, also supported with our public domain crypt_blowfish package (for C applications), and known in PHP as CRYPT_BLOWFISH, with a fallback to BSDI-style extended DES-based hashes, known in PHP as CRYPT_EXT_DES, and a last resort fallback to MD5-based salted and variable iteration count password hashes implemented in phpass itself (also referred to as portable hashes).
To ensure that the fallbacks will never occur, PHP 5.3.0+ or the Suhosin patch may be used. PHP 5.3.0+ and Suhosin integrate crypt_blowfish into the PHP interpreter such that bcrypt is available for use by PHP scripts even if the host system lacks support for it.
Comments
The Envato post says the passwords will be individually hashed and salted. The aMember forum has a few more details:
4.1.3 release: http://www.amember.com/forum/threads/amember-pro-version-4-1... states "Removed user.pass variable from email templates. Plain text password in not available anymore."
4.1.6 release: http://www.amember.com/forum/threads/amember-pro-version-4-1... states "Closes #448 - and do not save md5 passwords at all".
User issue: http://www.amember.com/forum/threads/urgent-amember-v4-1-12-... "Unfortunately, in the email received by customers, the password comes out encrypted like $P$BkTNDykCkTfsOqHwsV4TT2/"
The hash format indicates it's using PHPass: http://cvsweb.openwall.com/cgi/cvsweb.cgi/projects/phpass/Pa... which is based on MD5, but with the log of the number of rounds indicated by the first character after the $P$ prefix. In the forum example, it's "B" which is 11 making it 2^11 rounds. The remainder is an 8 character salt plus checksum. PHPass is authored by "Solar Designer" or Alexander Peslyak, also the author of John the Ripper and respected in the security community: http://en.wikipedia.org/wiki/Alexander_Peslyak so is likely pretty solid.
Solar Designer is great. Here's what his PHPass page says:
The preferred (most secure) hashing method supported by phpass is the OpenBSD-style Blowfish-based bcrypt, also supported with our public domain crypt_blowfish package (for C applications), and known in PHP as CRYPT_BLOWFISH, with a fallback to BSDI-style extended DES-based hashes, known in PHP as CRYPT_EXT_DES, and a last resort fallback to MD5-based salted and variable iteration count password hashes implemented in phpass itself (also referred to as portable hashes).
To ensure that the fallbacks will never occur, PHP 5.3.0+ or the Suhosin patch may be used. PHP 5.3.0+ and Suhosin integrate crypt_blowfish into the PHP interpreter such that bcrypt is available for use by PHP scripts even if the host system lacks support for it.