NAME

sshpk-sign - sign data using an SSH key

SYNOPSYS

sshpk-sign -i KEYPATH [OPTION...]

DESCRIPTION

Takes in arbitrary bytes, and signs them using an SSH private key. The key can be of any type or format supported by the sshpk library, including the standard OpenSSH formats, as well as PEM PKCS#1 and PKCS#8.

The signature is printed out in Base64 encoding, unless the --binary or -b option is given.

EXAMPLES

Signing with default settings:

$ printf 'foo' | sshpk-sign -i ~/.ssh/id_ecdsa
MEUCIAMdLS/vXrrtWFepwe...

Signing in SSH (RFC 4253) format (rather than the default ASN.1):

$ printf 'foo' | sshpk-sign -i ~/.ssh/id_ecdsa -t ssh
AAAAFGVjZHNhLXNoYTIt...

Saving the binary signature to a file:

$ printf 'foo' | sshpk-sign -i ~/.ssh/id_ecdsa \
                            -o signature.bin -b
$ cat signature.bin | base64
MEUCIAMdLS/vXrrtWFepwe...

OPTIONS

-v, --verbose: Print extra information about the key and signature to stderr when signing.
-b, --binary: Don't base64-encode the signature before outputting it.
-i KEY, --identity=KEY: Select the key to be used for signing. KEY must be a relative or absolute filesystem path to the key file. Any format supported by the sshpk library is supported, including OpenSSH formats and standard PEM PKCS.
-f PATH, --file=PATH: Input file to sign instead of stdin.
-o PATH, --out=PATH: Output file to save signature in instead of stdout.
-H HASH, --hash=HASH: Set the hash algorithm to be used for signing. This should be one of sha1, sha256 or sha512. Some key types may place restrictions on which hash algorithms may be used (e.g. ED25519 keys can only use SHA-512).
-t FORMAT, --format=FORMAT: Choose the signature format to use, from asn1, ssh or raw (only for ED25519 signatures). The asn1 format is the default, as it is the format used with TLS and typically the standard in most non-SSH libraries (e.g. OpenSSL). The ssh format is used in the SSH protocol and by the ssh-agent.

BUGS