openssl dgst
[-sha|-sha1|-mdc2|-ripemd160|-sha224|-sha256|-sha384|-sha512|-md2|-md4|-md5|-dss1]
[-c] [-d] [-hex] [-binary] [-r]
[-non-fips-allow] [-out filename] [-sign filename]
[-keyform arg] [-passin arg] [-verify filename]
[-prverify filename] [-signature filename] [-hmac key]
[-non-fips-allow] [-fips-fingerprint] [file...]
openssl [digest] [...]
The digest functions output the message digest of a supplied file
or files in hexadecimal. The digest functions also generate and verify
digital signatures using message digests.
- -c
- print out the digest in two digit groups separated by colons, only
relevant if hex format output is used.
- -d
- print out BIO debugging information.
- -hex
- digest is to be output as a hex dump. This is the default case for a
"normal" digest as opposed to a digital signature. See NOTES
below for digital signatures using -hex.
- -binary
- output the digest or signature in binary form.
- -r
- output the digest in the "coreutils" format used by programs
like sha1sum.
- -non-fips-allow
- Allow use of non FIPS digest when in FIPS mode. This has no effect when
not in FIPS mode.
- -out filename
- filename to output to, or standard output by default.
- -sign filename
- digitally sign the digest using the private key in
"filename".
- -keyform
arg
- Specifies the key format to sign digest with. The DER, PEM, P12, and
ENGINE formats are supported.
- -engine id
- Use engine id for operations (including private key storage). This
engine is not used as source for digest algorithms, unless it is also
specified in the configuration file.
- -sigopt
nm:v
- Pass options to the signature algorithm during sign or verify operations.
Names and values of these options are algorithm-specific.
- -passin
arg
- the private key password source. For more information about the format of
arg see the PASS PHRASE ARGUMENTS section in
openssl(1).
- -verify
filename
- verify the signature using the the public key in "filename". The
output is either "Verification OK" or "Verification
Failure".
- -prverify
filename
- verify the signature using the the private key in
"filename".
- -signature
filename
- the actual signature to verify.
- -hmac key
- create a hashed MAC using "key".
- -mac alg
- create MAC (keyed Message Authentication Code). The most popular MAC
algorithm is HMAC (hash-based MAC), but there are other MAC algorithms
which are not based on hash, for instance gost-mac algorithm,
supported by ccgost engine. MAC keys and other options should be
set via -macopt parameter.
- -macopt
nm:v
- Passes options to MAC algorithm, specified by -mac key. Following
options are supported by both by HMAC and gost-mac:
- key:string
- Specifies MAC key as alphnumeric string (use if key contain printable
characters only). String length must conform to any restrictions of the
MAC algorithm for example exactly 32 chars for gost-mac.
- hexkey:string
- Specifies MAC key in hexadecimal form (two hex digits per byte). Key
length must conform to any restrictions of the MAC algorithm for example
exactly 32 chars for gost-mac.
- -rand file(s)
- a file or files containing random data used to seed the random number
generator, or an EGD socket (see RAND_egd(3)). Multiple files can
be specified separated by a OS-dependent character. The separator is
; for MS-Windows, , for OpenVMS, and : for all
others.
- -non-fips-allow
- enable use of non-FIPS algorithms such as MD5 even in FIPS mode.
- -fips-fingerprint
- compute HMAC using a specific key for certain OpenSSL-FIPS
operations.
- file...
- file or files to digest. If no files are specified then standard input is
used.
To create a hex-encoded message digest of a file:
openssl dgst -md5 -hex file.txt
To sign a file using SHA-256 with binary file output:
openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt
To verify a signature:
openssl dgst -sha256 -verify publickey.pem \
-signature signature.sign \
file.txt
The digest of choice for all new applications is SHA1. Other
digests are however still widely used.
When signing a file, dgst will automatically determine the
algorithm (RSA, ECC, etc) to use for signing based on the private key's
ASN.1 info. When verifying signatures, it only handles the RSA, DSA, or
ECDSA signature itself, not the related data to identify the signer and
algorithm used in formats such as x.509, CMS, and S/MIME.
A source of random numbers is required for certain signing
algorithms, in particular ECDSA and DSA.
The signing and verify options should only be used if a single
file is being signed or verified.
Hex signatures cannot be verified using openssl. Instead,
use "xxd -r" or similar program to transform the hex signature
into a binary signature prior to verification.