NAME
dgst, sha, sha1, mdc2, ripemd160, sha224, sha256, sha384, sha512, md2, md4, md5,
dss1 - message digests
LIBRARY
libcrypto, -lcrypto
SYNOPSIS
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] [
...]
DESCRIPTION
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.
OPTIONS
- -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.
EXAMPLES
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
NOTES
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.