Creating a certificate is NOT signing the CSR, or even the CSR body. You need to create a cert body containing data that is partly the same as the CSR and partly different, and sign that.
First, do you have a CA cert (root or otherwise) matching the key in your HSM? If not, any cert(s) you do manage to create with that key won't be useful because software has no reason to trust it(them).
OpenSSL has an ENGINE API to allow HSMs or other "external" components to handle some crypto operations, including RSA.
This API is intended to be simple enough that new engines can easily be added. If there is an engine module already compatible with your HSM or you can get one, you can just use the same
openssl commandline operations openssl ca or openssl x509 -req -CA* with explicit -engine option or the equivalent in your config file. If your HSM supports a PKCS#11 interface,
there is a generic but thirdparty pkcs11 engine for OpenSSL, see https://stackoverflow.com/questions/19456555/openssl-engine-pkcs11-libp11-opensc .
Or you can as @Z.T. comments write a program that calls libcrypto to do most of the same things the commandline apps do, except using your HSM to do the signature.
I suggest looking at the reqfile case in apps/x509.c as a starting point; ca.c has so many more options it's a bit harder to extract what you actually need. You'll also need to replace X509_sign, which is really just ASN1_item_sign with X509_CINF as the encoded type, with an explicit encoding step i2d_x509_CINF(x->cert_info,...) followed by digest, encode/pad, and sign as per PKCS#1/rfc3447 (and rfc3279).
As a last resort you could:
- create a fake issuer keypair with the same algorithm (RSA) and size, and fake issuer cert for that keypair but with the same names, and keyid if used, as the real CA cert;
the keyid won't match the key as openssl sets automatically so you'll have to encode the explicit value
- use openssl commandline as-is to process your CSR and issue a bastard cert under the fake issuer keypair and cert (add) with right hash, so it has all the correct data in the cert body (add) and algids but a wrong signature
- split the DER encoded cert into the outer wrapper, "to-be-signed" body, algid, and wrong signature
- have your HSM sign the encoded/padded digest of body with the real CA key giving a good signature
- recombine the outer wrapper, body, and algid with the good signature
Expanded third option per comment. I realized x509 can copy an existing subjectkeyid without computing it on the actual (new) key, so that part is easier; note this feature requires the fairly-recent version 1.0.2 of OpenSSL.
Also on going through the steps I realized your device is signing with SHA-1. Because MD5 was broken several years ago for collision, and thus signature at least in a potentially adversarial situation like cert issuance, and the consensus of cryptography experts is that essentially the same techniques will work soon against SHA-1, cert signature using SHA-1 has been officially disapproved since 2013 by NIST, and prohibited by CA/Browser Forum for certs lasting beyond next year (2016) and some people are actively pushing to make it sooner. There are already dozens of questions here and some other SEs about this: "Why does Chrome warn my cert is about to be insecure?" "SHA-1 is obsolete, you need to get a new one." "How can I shut off all the warnings clogging my Firefox console about SHA-1 certs?" "You can't, that's a feature." Browsers may, with sufficient manual overrides, continue to accept SHA1 signatures from private in-house CAs like yours, where the collision risk is mitigated, but it may become more difficult, especially if the users of your system(s) are not crypto experts.
Those said, here's a worked example on Windows, which is the slightly harder case:
:: contents of conf.txt
[req]
# to generate CSR (and also fake HSM)
distinguished_name = reqdn
[reqdn]
# dummy, actual values on commandline
[myca]
# to issue "bastard" cert which will be patched
private_key = fakekey.pem
certificate = fakecert.pem
default_days = 365
database = index.txt
serial = serial
new_certs_dir = .
policy = policy_anything
x509_extensions = user
[ policy_anything ]
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
[HSMCA]
# to fake HSM only
basicConstraints=CA:true
keyUsage = keyCertSign
subjectKeyIdentifier = hash
#authorityKeyIdentifer not needed
[user]
# for issued certs
keyUsage = digitalSignature, keyEncipherment
authorityKeyIdentifier = keyid
# could be omitted or 'issuer' additionally or instead
subjectAltName=DNS:example.com,DNS:*.example.com
# canned value for example, reality should be copy-from-req or dynamic
:: simulate for example "real" (HSM) key and CA cert for it
C:\temp>openssl req -newkey rsa:2048 -x509 -subj "/C=QQ/O=McKean/OU=HSMCA" -days 3650 ^
-config conf.txt -extensions HSMCA -nodes -keyout hsmkey.pem -out hsmcert.pem
Loading 'screen' into random state - done
Generating a 2048 bit RSA private key
..........................+++
..........................+++
unable to write 'random state'
writing new private key to 'hsmkey.pem'
C:\temp>openssl x509 <hsmcert.pem -noout -text
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
c3:1e:19:f6:87:e0:8e:90
Signature Algorithm: sha256WithRSAEncryption
Issuer: C=QQ, O=McKean, OU=HSMCA
Validity
Not Before: Oct 16 02:38:16 2015 GMT
Not After : Oct 13 02:38:16 2025 GMT
Subject: C=QQ, O=McKean, OU=HSMCA
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
00:ba:f1:da:4a:2b:24:8c:de:1b:cc:b8:e4:30:a5:
17:bc:d2:a9:93:8c:cc:ee:91:98:99:83:ee:81:d3:
80:e5:9c:ec:5d:97:c3:2f:8e:e6:db:52:e0:af:a1:
c6:f4:6e:78:90:32:3a:8c:09:a5:78:34:76:44:98:
04:83:03:41:59:f0:0b:7e:13:02:20:a0:70:cb:eb:
32:52:c8:62:ee:1c:97:a3:c9:64:14:0a:73:85:9d:
e3:16:90:96:3d:e1:e7:3a:39:a8:95:64:68:8f:e4:
eb:29:62:36:ff:e6:e7:89:d6:5a:8f:b0:03:cb:38:
e4:dc:6a:9d:5b:9c:5d:1a:4e:13:5c:22:5a:cf:e6:
92:a5:42:82:44:c7:07:46:f4:db:57:97:04:e6:b3:
7b:88:3b:14:ff:c7:dd:87:7a:e3:14:f6:84:ef:09:
9e:44:7b:e1:81:a9:3d:c6:a6:5f:77:ee:02:6e:74:
a6:b8:d9:30:88:8e:b4:48:b3:f0:ab:c9:87:5c:db:
5d:df:05:28:b1:34:b7:20:32:be:b7:a2:77:7d:bf:
7f:62:57:88:c3:c9:4c:4d:29:63:cc:a3:dc:b2:b3:
00:8c:69:17:f9:d1:6c:02:31:9d:ca:03:6f:c2:a0:
ef:61:14:66:07:57:e6:9c:44:7d:ed:22:e4:e9:f8:
7f:83
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Basic Constraints:
CA:TRUE
X509v3 Key Usage:
Certificate Sign
X509v3 Subject Key Identifier:
F7:A0:68:EB:7F:28:BC:4C:80:03:CA:57:C7:F0:61:7B:D6:14:C3:EC
Signature Algorithm: sha256WithRSAEncryption
1c:78:16:42:f4:29:7c:1e:a9:fb:b6:7f:15:12:8e:d1:e6:c6:
c3:11:dc:f2:fe:6b:3d:05:4b:0b:bc:cc:f8:29:ce:29:c1:a4:
11:8d:c1:c1:83:b7:4c:6e:f6:51:86:3a:08:2b:e5:a2:2e:ca:
23:09:d5:13:6d:c9:fe:b9:af:c4:ed:6f:75:d5:ef:a7:3e:4b:
7d:09:5b:ad:0d:3b:85:c4:fb:99:dd:a3:b1:e6:f7:34:25:f9:
c7:8e:37:fd:0d:20:85:cd:04:80:4b:b0:fc:46:4e:5b:a1:3a:
4c:ce:a3:17:a0:f9:41:f1:64:2e:ac:96:5a:f1:72:5b:9d:57:
0c:32:8e:cf:9b:ed:50:bf:88:28:c1:b2:bc:e1:87:3e:7b:ac:
f1:f0:3c:c7:5c:25:0d:da:38:f0:33:e0:25:03:88:f8:97:2c:
8c:a6:54:92:11:4d:36:9c:9f:3c:40:bb:3c:09:50:4b:f5:6e:
85:10:bb:dc:d9:67:8f:40:03:d1:95:a5:85:05:c2:65:f5:52:
18:a2:4d:59:7d:3f:5e:7a:f9:8c:e1:ca:ec:f8:05:4c:5c:74:
b6:04:f0:18:27:c5:a5:c6:d4:55:56:f9:80:1a:01:78:ab:51:
8c:c0:69:64:eb:09:ee:d8:f0:62:b9:f9:04:3c:d7:50:67:9e:
23:a6:69:ea
:: create "fake" RSA key of same size, and fake CA cert for it
:: with same subject, issuer/serial and keyid as the HSM cert
:: (validity period differs, but that doesn't matter)
C:\temp>openssl genrsa 2048 -nodes >fakekey.pem
Loading 'screen' into random state - done
Generating RSA private key, 2048 bit long modulus
.....................................+++
..........................................................................+++
unable to write 'random state'
e is 65537 (0x10001)
C:\temp>openssl rsa <fakekey.pem -noout -text
Private-Key: (2048 bit)
modulus:
00:98:07:94:79:39:14:c5:c7:64:8b:51:d3:9b:e1:
[remainder snipped]
C:\temp>openssl rsa <fakekey.pem -pubout >fakepub.pem
writing RSA key
C:\temp>openssl x509 <hsmcert.pem -force_pubkey fakepub.pem -signkey fakekey.pem >fakecert.pem
Loading 'screen' into random state - done
Getting Private key
unable to write 'random state'
C:\temp>openssl x509 <fakecert.pem -noout -text
Certificate:
Data:
Version: 3 (0x2)
Serial Number:
c3:1e:19:f6:87:e0:8e:90
Signature Algorithm: sha256WithRSAEncryption
Issuer: C=QQ, O=McKean, OU=HSMCA
Validity
Not Before: Oct 16 02:53:15 2015 GMT
Not After : Nov 15 02:53:15 2015 GMT
Subject: C=QQ, O=McKean, OU=HSMCA
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
00:98:07:94:79:39:14:c5:c7:64:8b:51:d3:9b:e1:
1b:0c:e7:f8:10:15:c6:95:b2:7d:81:66:2b:0a:ac:
82:2d:d2:86:72:84:f2:8c:d3:09:8a:d6:01:f4:d5:
73:cc:4b:6a:8a:3f:4c:e0:78:41:98:74:26:ab:07:
db:06:66:eb:63:23:27:f6:fa:d8:cf:7f:93:c6:65:
72:61:3d:c8:f5:db:5d:45:ac:4f:4e:a9:91:9b:af:
5e:4b:d1:61:9a:6c:42:de:87:56:ec:11:d0:64:12:
23:24:6a:8b:4c:b9:b2:68:97:8e:43:2e:9b:ad:1c:
1e:f5:f9:fa:69:6a:99:d7:ab:db:3f:7b:a9:dc:44:
b4:49:4c:95:7a:9b:ad:a1:69:84:b5:bc:fb:66:be:
58:0a:df:2c:8a:01:a6:7c:38:a6:10:e7:48:ed:72:
37:09:ea:fc:bf:1b:9c:27:49:8b:43:32:01:9a:1d:
aa:00:ba:88:2e:d0:1b:14:93:9e:5b:33:f9:12:03:
08:9e:9f:22:06:be:c7:85:3f:39:ae:41:f8:63:0e:
92:08:55:9b:82:6f:a7:b1:d2:df:f6:3a:2f:97:88:
9f:be:17:df:40:f0:89:de:1a:94:dd:63:10:75:3c:
dc:a1:c4:15:ca:e9:3b:26:81:6e:7b:58:52:79:72:
09:47
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Basic Constraints:
CA:TRUE
X509v3 Key Usage:
Certificate Sign
X509v3 Subject Key Identifier:
F7:A0:68:EB:7F:28:BC:4C:80:03:CA:57:C7:F0:61:7B:D6:14:C3:EC
Signature Algorithm: sha256WithRSAEncryption
97:5b:8b:4b:e4:e0:04:b0:b5:bd:68:09:a1:18:f2:19:68:76:
ea:be:e8:01:42:04:0a:c1:4c:a9:4f:4f:54:31:46:6c:cd:d2:
5a:4c:9d:af:9d:f3:99:8b:a5:ec:c3:38:7e:24:3a:6c:a0:4e:
7b:96:c2:88:9f:31:fc:93:47:57:fa:7c:4e:79:40:e6:ed:89:
b4:f5:42:17:d8:37:20:79:a6:2a:30:ce:f9:18:51:f0:a2:02:
7b:cb:8b:b5:41:92:79:4f:ce:ec:99:e1:a5:82:24:ec:e5:3d:
a1:ec:d1:6c:63:75:41:90:b6:af:15:17:f4:a1:8b:f7:8b:a5:
09:99:f9:aa:57:f7:98:ae:bc:ef:39:aa:6c:96:66:66:8b:65:
3a:b5:11:1f:d2:d6:b3:4d:95:0a:22:e7:3d:88:1f:ce:1c:3a:
04:c3:4f:33:e3:53:27:1d:94:10:98:4b:f6:70:ed:48:f1:ac:
ac:91:1a:5e:4a:37:9a:eb:58:39:69:89:d0:0e:1e:e5:7b:be:
51:bc:54:ae:09:dd:e5:8f:1f:41:0e:11:b7:e0:87:94:ba:9e:
d3:9b:69:04:02:fa:55:94:b0:43:bb:e9:15:ac:5c:a9:78:0d:
ae:1c:34:b1:ca:a7:d0:d4:78:5b:ec:35:1a:07:95:68:48:58:
fe:22:82:49
:: create user key and CSR for it, then issue bastard cert under fake key (with SHA1)
C:\temp>openssl req -newkey rsa:2048 -subj "/C=QQ/O=McKean/OU=server/CN=example.com" ^
-config conf.txt -nodes -keyout userkey.pem -out userreq.pem
Loading 'screen' into random state - done
Generating a 2048 bit RSA private key
................................................................................
.................................................................+++
...............+++
unable to write 'random state'
writing new private key to 'userkey.pem'
-----
C:\temp>echo 01 >serial
C:\temp>echo |set/p x= >index.txt
C:\temp>openssl ca -config conf.txt -name myca -in userreq.pem -md sha1 -notext -out bastard.pem
Using configuration from conf.txt
Loading 'screen' into random state - done
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
countryName :PRINTABLE:'QQ'
organizationName :ASN.1 12:'McKean'
organizationalUnitName:ASN.1 12:'server'
commonName :ASN.1 12:'example.com'
Certificate is to be certified until Oct 15 03:52:16 2016 GMT (365 days)
Sign the certificate? [y/n]:y
1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated
unable to write 'random state'
C:\temp>openssl x509 <bastard.pem -noout -text
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 1 (0x1)
Signature Algorithm: sha1WithRSAEncryption
Issuer: C=QQ, O=McKean, OU=HSMCA
Validity
Not Before: Oct 16 03:52:16 2015 GMT
Not After : Oct 15 03:52:16 2016 GMT
Subject: C=QQ, O=McKean, OU=server, CN=example.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
00:ad:9b:ea:c9:f1:fa:80:b6:9f:b4:6e:47:aa:9b:
f7:32:cf:2b:b9:44:f2:41:f3:42:10:dc:0a:58:6f:
8a:6b:71:2b:5d:93:a3:74:72:20:95:1a:db:9e:9c:
ae:d0:af:b7:da:11:f7:26:af:36:13:54:8f:b9:45:
d8:dd:5c:1c:a7:c7:c8:8f:b9:4d:09:f5:30:c3:2b:
d7:2c:c1:fa:25:78:91:51:22:61:aa:eb:8c:f4:d3:
47:80:7e:33:c0:9c:91:14:7d:97:fa:4c:72:28:73:
b5:41:7a:cc:5c:4f:da:4f:4d:6c:72:1e:65:b4:47:
1a:31:ff:1f:b9:e2:55:c5:c4:2c:d0:28:c9:e1:0c:
60:87:2c:0a:0b:21:9c:23:ee:86:a1:57:06:62:68:
8b:46:3b:07:2a:08:5c:6f:42:74:5b:53:a6:3e:ba:
ed:16:4d:64:c5:17:4a:8b:45:7e:fb:23:e7:63:94:
01:b1:c0:45:0d:7d:45:d0:fe:2d:1e:b0:d6:14:25:
45:2a:f7:3a:28:14:fe:67:0b:9b:7e:67:90:a2:84:
90:f5:de:55:3a:94:ad:4f:fc:80:e4:60:6d:7a:7c:
06:7f:aa:69:e2:22:39:e3:13:ae:20:f8:14:f8:55:
bd:3a:e7:6b:23:a0:b1:54:9f:bf:af:56:cc:77:32:
7e:27
Exponent: 65537 (0x10001)
X509v3 extensions:
X509v3 Key Usage:
Digital Signature, Key Encipherment
X509v3 Authority Key Identifier:
keyid:F7:A0:68:EB:7F:28:BC:4C:80:03:CA:57:C7:F0:61:7B:D6:14:C3:EC
X509v3 Subject Alternative Name:
DNS:example.com, DNS:*.example.com
Signature Algorithm: sha1WithRSAEncryption
24:4c:01:bf:b3:73:8f:16:03:d5:fd:34:55:e8:7c:de:be:1f:
99:92:88:b7:df:97:a3:a3:9e:2e:31:78:22:b8:ea:12:ff:3b:
10:ff:d3:56:4f:5d:77:8c:21:d4:65:87:56:42:e5:91:e6:d7:
68:b6:09:2e:22:b6:2e:d2:d7:6c:a4:3f:fa:98:57:f9:e3:61:
fd:49:90:e7:9c:3d:42:36:19:68:8e:be:a3:77:3d:94:41:54:
81:46:e4:bd:0b:5a:96:6e:de:28:00:36:39:a1:27:0a:84:2d:
19:b2:3d:19:d7:97:c9:a7:3f:f2:0a:71:d8:21:4a:64:6b:25:
85:c2:1e:f4:bf:e1:01:1c:96:64:6f:33:d6:8d:46:c2:85:3c:
e7:fb:15:95:75:bb:cf:0c:a5:8f:6d:a3:a8:51:3b:fe:8d:cc:
27:d1:b7:13:c8:90:60:6a:fa:ba:7e:47:53:51:f5:89:bc:f0:
55:e7:bd:fc:29:59:0f:6e:99:e6:53:bc:87:9f:a1:23:6f:cb:
8f:d3:58:53:a3:05:40:54:38:6e:df:34:83:86:34:9d:5d:21:
9f:26:e9:53:e3:f1:fd:a9:8e:be:b8:64:48:d7:8d:80:a2:de:
4a:86:fc:99:a0:08:b3:62:2b:ed:9d:38:05:ae:2a:88:75:71:
cd:3c:89:c1
:: find parts of cert
C:\temp>openssl asn1parse -i <bastard.pem
0:d=0 hl=4 l= 837 cons: SEQUENCE
4:d=1 hl=4 l= 557 cons: SEQUENCE
8:d=2 hl=2 l= 3 cons: cont [ 0 ]
10:d=3 hl=2 l= 1 prim: INTEGER :02
13:d=2 hl=2 l= 1 prim: INTEGER :01
16:d=2 hl=2 l= 13 cons: SEQUENCE
18:d=3 hl=2 l= 9 prim: OBJECT :sha1WithRSAEncryption
29:d=3 hl=2 l= 0 prim: NULL
31:d=2 hl=2 l= 46 cons: SEQUENCE
33:d=3 hl=2 l= 11 cons: SET
35:d=4 hl=2 l= 9 cons: SEQUENCE
37:d=5 hl=2 l= 3 prim: OBJECT :countryName
42:d=5 hl=2 l= 2 prim: PRINTABLESTRING :QQ
46:d=3 hl=2 l= 15 cons: SET
48:d=4 hl=2 l= 13 cons: SEQUENCE
50:d=5 hl=2 l= 3 prim: OBJECT :organizationName
55:d=5 hl=2 l= 6 prim: UTF8STRING :McKean
63:d=3 hl=2 l= 14 cons: SET
65:d=4 hl=2 l= 12 cons: SEQUENCE
67:d=5 hl=2 l= 3 prim: OBJECT :organizationalUnitName
72:d=5 hl=2 l= 5 prim: UTF8STRING :HSMCA
79:d=2 hl=2 l= 30 cons: SEQUENCE
81:d=3 hl=2 l= 13 prim: UTCTIME :151016035216Z
96:d=3 hl=2 l= 13 prim: UTCTIME :161015035216Z
111:d=2 hl=2 l= 69 cons: SEQUENCE
113:d=3 hl=2 l= 11 cons: SET
115:d=4 hl=2 l= 9 cons: SEQUENCE
117:d=5 hl=2 l= 3 prim: OBJECT :countryName
122:d=5 hl=2 l= 2 prim: PRINTABLESTRING :QQ
126:d=3 hl=2 l= 15 cons: SET
128:d=4 hl=2 l= 13 cons: SEQUENCE
130:d=5 hl=2 l= 3 prim: OBJECT :organizationName
135:d=5 hl=2 l= 6 prim: UTF8STRING :McKean
143:d=3 hl=2 l= 15 cons: SET
145:d=4 hl=2 l= 13 cons: SEQUENCE
147:d=5 hl=2 l= 3 prim: OBJECT :organizationalUnitName
152:d=5 hl=2 l= 6 prim: UTF8STRING :server
160:d=3 hl=2 l= 20 cons: SET
162:d=4 hl=2 l= 18 cons: SEQUENCE
164:d=5 hl=2 l= 3 prim: OBJECT :commonName
169:d=5 hl=2 l= 11 prim: UTF8STRING :example.com
182:d=2 hl=4 l= 290 cons: SEQUENCE
186:d=3 hl=2 l= 13 cons: SEQUENCE
188:d=4 hl=2 l= 9 prim: OBJECT :rsaEncryption
199:d=4 hl=2 l= 0 prim: NULL
201:d=3 hl=4 l= 271 prim: BIT STRING
476:d=2 hl=2 l= 87 cons: cont [ 3 ]
478:d=3 hl=2 l= 85 cons: SEQUENCE
480:d=4 hl=2 l= 11 cons: SEQUENCE
482:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Key Usage
487:d=5 hl=2 l= 4 prim: OCTET STRING [HEX DUMP]:030205A0
493:d=4 hl=2 l= 31 cons: SEQUENCE
495:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Authority Key Identfier
500:d=5 hl=2 l= 24 prim: OCTET STRING [HEX DUMP]:30168014F7A068EBF28BC4C8003CA57C7F0617BD614C3EC
526:d=4 hl=2 l= 37 cons: SEQUENCE
528:d=5 hl=2 l= 3 prim: OBJECT :X509v3 Subject AlternativeName
533:d=5 hl=2 l= 30 prim: OCTET STRING [HEX DUMP]:301C820B6578616D06C652E636F6D820D2A2E6578616D706C652E636F6D
565:d=1 hl=2 l= 13 cons: SEQUENCE
567:d=2 hl=2 l= 9 prim: OBJECT :sha1WithRSAEncryption
578:d=2 hl=2 l= 0 prim: NULL
580:d=1 hl=4 l= 257 prim: BIT STRING
:: For this cert: outer TL is 0 to 4, body is 4 to 565, algid is 565 to 580,
:: BITSTRING TL+unused is 580 to 585, and actual signature is 585 to 841
:: separate the pieces; on Unix could use a bunch of dd,
:: but perl is easier and (nearly) the same on Windows
C:\temp>openssl x509 <bastard.pem >bastard.der -outform der
C:\temp>type bastard.pl
open F, '<bastard.der' or die $!; binmode F;
my $b; my $i=0; foreach my $n (@ARGV){
($n-=tell(F)) > 0 or die "out of order";
open G, '>bastard.'.(++$i) or die $!; binmode G;
read F,$b,$n; print G $b; close(G); }
C:\temp>perl bastard.pl 4 565 580 999
C:\temp>dir bastard.?
[skip]
2015-10-16 00:48 4 bastard.1
2015-10-16 00:48 561 bastard.2
2015-10-16 00:48 20 bastard.3
2015-10-16 00:48 256 bastard.4
[skip]
:: simulate HSM signature on body with SHA1,RSASSA-PKCS1v1.5
:: doing this on the real HSM remains your problem,
:: and if you (need to) write a program
:: it might easily handle the split and recombine too
C:\temp>openssl dgst -sha1 <bastard.2 -sign hsmkey.pem >bastard.x
C:\temp>dir bastard.x
[skip]
2015-10-16 00:52 256 bastard.x
[skip]
:: recombine substituting HSM signature (on Unix just cat)
C:\temp>copy /b bastard.1+bastard.2+bastard.3+bastard.x fixed.der
:: convert back to PEM and check result
C:\temp>openssl x509 <fixed.der -inform der >fixed.pem
C:\temp>openssl verify -CAfile hsmcert.pem fixed.pem
fixed.pem: OK
