########## signature check:

$ gpg --keyid-format long openssl-1.1.1s.tar.gz.asc
gpg: Signature made Tue 01 Nov 2022 08:36:17 AM EDT
gpg:                using RSA key 527466A21CA79E6D
gpg: Can't check signature: No public key

$ gpg --keyserver hkps://keyserver.ubuntu.com --recv-keys 527466A21CA79E6D
gpg: requesting key 1CA79E6D from hkps server keyserver.ubuntu.com
gpg: key A9DA2D5C: public key "Tomáš Mráz <tm@t8m.info>" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)

$ gpg openssl-1.1.1s.tar.gz.asc
gpg: Signature made Tue 01 Nov 2022 08:36:17 AM EDT using RSA key ID 1CA79E6D
gpg: Good signature from "Tomáš Mráz <tm@t8m.info>"
gpg:                 aka "Tomáš Mráz <tomas@arleto.cz>"
gpg:                 aka "Tomáš Mráz <tomas@openssl.org>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: A21F AB74 B008 8AA3 6115  2586 B8EF 1A6B A9DA 2D5C
     Subkey fingerprint: DC70 3266 2AF8 85E2 F47F  243F 5274 66A2 1CA7 9E6D

########## file check and extract:

$ gzip -d < openssl-1.1.1s.tar.gz | tar tvf - | head
drwxrwxr-x root/root         0 2022-11-01 08:36 openssl-1.1.1s/
-rw-rw-r-- root/root        87 2022-11-01 08:36 openssl-1.1.1s/ACKNOWLEDGEMENTS
-rw-rw-r-- root/root       854 2022-11-01 08:36 openssl-1.1.1s/AUTHORS
-rw-rw-r-- root/root    605265 2022-11-01 08:36 openssl-1.1.1s/CHANGES
-rw-rw-r-- root/root      3627 2022-11-01 08:36 openssl-1.1.1s/CONTRIBUTING
drwxrwxr-x root/root         0 2022-11-01 08:36 openssl-1.1.1s/Configurations/
-rw-rw-r-- root/root     11582 2022-11-01 08:36 openssl-1.1.1s/Configurations/00-base-templates.conf
-rw-rw-r-- root/root     81204 2022-11-01 08:36 openssl-1.1.1s/Configurations/10-main.conf
-rw-rw-r-- root/root     11680 2022-11-01 08:36 openssl-1.1.1s/Configurations/15-android.conf
-rw-rw-r-- root/root      2411 2022-11-01 08:36 openssl-1.1.1s/Configurations/15-ios.conf

$ gzip -d < openssl-1.1.1s.tar.gz | tar tvf - | awk '{ print $6 }' | head
openssl-1.1.1s/
openssl-1.1.1s/ACKNOWLEDGEMENTS
openssl-1.1.1s/AUTHORS
openssl-1.1.1s/CHANGES
openssl-1.1.1s/CONTRIBUTING
openssl-1.1.1s/Configurations/
openssl-1.1.1s/Configurations/00-base-templates.conf
openssl-1.1.1s/Configurations/10-main.conf
openssl-1.1.1s/Configurations/15-android.conf
openssl-1.1.1s/Configurations/15-ios.conf
$ gzip -d < openssl-1.1.1s.tar.gz | tar tvf - | awk '{ print $6 }' | awk -F/ '{ print $1 }' | sort -u
openssl-1.1.1s

$ gzip -d < openssl-1.1.1s.tar.gz | tar tvf - | fgrep '..'
$
$ gzip -d < openssl-1.1.1s.tar.gz | tar xf -

########## configure, make, make test, make install:

$ ./config --prefix=/opt/openssl-1.1.1s --openssldir=/etc/local/ssl no-shared < /dev/null >& config.sh.log

$ make < /dev/null >& make-make.log

$ make test < /dev/null >& make-test.log

# mkdir /opt/openssl-1.1.1s; chown rperry:rperry /opt/openssl-1.1.1s

$ make install < /dev/null >& make-install.log

$ make distclean

# chown -Rh root:root /opt/openssl-1.1.1s
# cd /opt && rm openssl && ln -s openssl-1.1.1s openssl
# ls -ld /opt/openssl* /opt/bin/openssl
lrwxrwxrwx 1 root   root   22 Apr  4  2018 /opt/bin/openssl -> ../openssl/bin/openssl
lrwxrwxrwx 1 root   root   14 Nov  3 09:09 /opt/openssl -> openssl-1.1.1s
drwxr-xr-x 6 root   root   52 May  3  2022 /opt/openssl-1.1.1o
drwxr-xr-x 6 root   root   52 Jun 21 11:02 /opt/openssl-1.1.1p
drwxr-xr-x 6 root   root   52 Nov  3 09:08 /opt/openssl-1.1.1s
#

$ which openssl
/opt/bin/openssl
$ openssl version
OpenSSL 1.1.1s  1 Nov 2022
$

########## BIGNUM structure::

$ find . -name '*.h' -print | xargs grep 'typedef.*BIGNUM'
./include/openssl/ossl_typ.h:typedef struct bignum_st BIGNUM;
$ find . -name '*.h' -print | xargs grep 'struct bignum_st'
./crypto/bn/bn_local.h:struct bignum_st {
./include/openssl/ossl_typ.h:typedef struct bignum_st BIGNUM;
$ less crypto/bn/bn_local.h
...
struct bignum_st {
    BN_ULONG *d;                /* Pointer to an array of 'BN_BITS2' bit
                                 * chunks. */
    int top;                    /* Index of last used d +1. */
    /* The next are internal book keeping for bn_expand. */
    int dmax;                   /* Size of the d array. */
    int neg;                    /* one if the number is negative */
    int flags;
};
...