Connect_Ftp2 AuthTls: 1 AuthSsl: 0 authTls: sendCommand: sendingCommand: AUTH TLS --sendCommand readCommandResponse: replyLineQP: 234 start TLS negotiation --readCommandResponse clientHandshake: clientHandshake2: buildClientKeyExchange: buildClientKeyExchangeRsa: RSA key size is too small. minAcceptableRsaSize: 1024 tooSmallKeySize: 512 --buildClientKeyExchangeRsa --buildClientKeyExchange Failed to build ClientKeyExchange sendFatalAlert: Closing connection after sending fatal TLS alert. --sendFatalAlert --clientHandshake2 --clientHandshake Client handshake failed. (1) connectionClosed: 0 Failed to convert channel to SSL/TLS --authTls --ftpConnect Failed to connect to FTP server. Failed. --Connect_Ftp2 --ChilkatLog
How can I change minAcceptableRsaSize?
First, make sure you are using the latest version of the Chilkat library. Then I think the SslAllowedCiphers property might be what you need. I suggest appending "rsa512" to the list of allowed ciphers to see if that helps. See the documentation below:
SslAllowedCiphers As String Introduced in version 220.127.116.11
Provides a means for setting a list of ciphers that are allowed for SSL/TLS connections. The default (empty string) indicates that all implemented ciphers are possible: aes256-cbc, aes128-cbc, 3des-cbc, and rc4. To restrict SSL/TLS connections to one or more specific ciphers, set this property to a comma-separated list of ciphers such as "aes256-cbc, aes128-cbc". The order should be in terms of preference, with the preferred algorithms listed first. The server however, chooses from among the algorithms listed.
Starting in v18.104.22.168, Chilkat will by-default disallow all possible usage of RSA keys that are less than 1024 bits. To allow for 512 bits or above, add "rsa512" to the list of algorithms in the SslAllowedCiphers list. To allow only 2048 bits or above, add "rsa2048" to the list of algorithms. (Adding "rsa1024" chooses the same as the default.)