briansmith · October 6, 2025 11:37 · Nov 9, 2017 · May 17, 2017 · May 15, 2017 · May 15, 2017
diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -35,7 +35,7 @@ which is what software for signing and verifying ECDSA signatures expects.
 openssl genpkey -algorithm EC \
     -pkeyopt ec_paramgen_curve:P-256 \
     -pkeyopt ec_param_enc:named_curve | \
-  openssl pkcs8 -top8 -nocrypt -outform der > p256-private-key.p8
+  openssl pkcs8 -topk8 -nocrypt -outform der > p256-private-key.p8
 ```
 
 #### ECC P-384
@@ -44,7 +44,7 @@ openssl genpkey -algorithm EC \
 openssl genpkey -algorithm EC \
     -pkeyopt ec_paramgen_curve:P-384 \
     -pkeyopt ec_param_enc:named_curve |
-  openssl pkcs8 -top8 -nocrypt -outform der > p384-private-key.p8
+  openssl pkcs8 -topk8 -nocrypt -outform der > p384-private-key.p8
 ```
 
 ### RSA
@@ -64,7 +64,7 @@ RSA-PSS signatures.
 openssl genpkey -algorithm RSA \
     -pkeyopt rsa_keygen_bits:2048 \
     -pkeyopt rsa_keygen_pubexp:65537 | \
-  openssl pkcs8 -top8 -nocrypt -outform der > rsa-2048-private-key.p8
+  openssl pkcs8 -topk8 -nocrypt -outform der > rsa-2048-private-key.p8
 ```
 
 #### 3072-bit RSA 
@@ -73,7 +73,7 @@ openssl genpkey -algorithm RSA \
 openssl genpkey -algorithm RSA \
     -pkeyopt rsa_keygen_bits:3072 \
     -pkeyopt rsa_keygen_pubexp:65537 | \
-  openssl pkcs8 -top8 -nocrypt -outform der > rsa-3072-private-key.p8
+  openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.p8
 ```
 
 ## Extracting the Public Key from the Private Key as a SubjectPublicKeyInfo.

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -35,7 +35,7 @@ which is what software for signing and verifying ECDSA signatures expects.
 openssl genpkey -algorithm EC \
     -pkeyopt ec_paramgen_curve:P-256 \
     -pkeyopt ec_param_enc:named_curve | \
-  openssl pkcs8 -topk8 -nocrypt -outform der > p256-private-key.pk8
+  openssl pkcs8 -top8 -nocrypt -outform der > p256-private-key.p8
 ```
 
 #### ECC P-384
@@ -44,7 +44,7 @@ openssl genpkey -algorithm EC \
 openssl genpkey -algorithm EC \
     -pkeyopt ec_paramgen_curve:P-384 \
     -pkeyopt ec_param_enc:named_curve |
-  openssl pkcs8 -topk8 -nocrypt -outform der > p384-private-key.pk8
+  openssl pkcs8 -top8 -nocrypt -outform der > p384-private-key.p8
 ```
 
 ### RSA
@@ -64,7 +64,7 @@ RSA-PSS signatures.
 openssl genpkey -algorithm RSA \
     -pkeyopt rsa_keygen_bits:2048 \
     -pkeyopt rsa_keygen_pubexp:65537 | \
-  openssl pkcs8 -topk8 -nocrypt -outform der > rsa-2048-private-key.pk8
+  openssl pkcs8 -top8 -nocrypt -outform der > rsa-2048-private-key.p8
 ```
 
 #### 3072-bit RSA 
@@ -73,7 +73,7 @@ openssl genpkey -algorithm RSA \
 openssl genpkey -algorithm RSA \
     -pkeyopt rsa_keygen_bits:3072 \
     -pkeyopt rsa_keygen_pubexp:65537 | \
-  openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.pk8
+  openssl pkcs8 -top8 -nocrypt -outform der > rsa-3072-private-key.p8
 ```
 
 ## Extracting the Public Key from the Private Key as a SubjectPublicKeyInfo.
@@ -91,25 +91,25 @@ Examples:
 
 ```sh
 openssl pkey -pubout -inform der -outform der \
-    -in p256-private-key.pk8 \
+    -in p256-private-key.p8 \
     -out p256-public-key.spki
 ```
 
 ```sh
 openssl pkey -pubout -inform der -outform der \
-    -in p384-private-key.pk8 \
+    -in p384-private-key.p8 \
     -out p384-public-key.spki
 ```
 
 ```sh
 openssl pkey -pubout -inform der -outform der \
-    -in rsa-2048-private-key.pk8 \
+    -in rsa-2048-private-key.p8 \
     -out rsa-2048-public-key.spki
 ```
 
 ```sh
 openssl pkey -pubout -inform der -outform der \
-    -in rsa-3072-private-key.pk8 \
+    -in rsa-3072-private-key.p8 \
     -out rsa-3072-public-key.spki
 ```
 
@@ -122,7 +122,7 @@ format then can do the conversion following this example:
 
 ```sh
 openssl pkey -pubout -inform der -outform der \
-    -in rsa-2048-private-key.pk8 | \
+    -in rsa-2048-private-key.p8 | \
   openssl rsa -pubin -RSAPublicKey_out -inform DER -outform DER \
     -out rsa-2048-public-key-legacy-form.der
 ```
@@ -131,7 +131,7 @@ The Base64 (“PEM”) form can be output following this example:
 
 ```sh
 openssl pkey -pubout -inform der -outform der \
-    -in rsa-2048-private-key.pk8 | \
+    -in rsa-2048-private-key.p8 | \
   openssl rsa -pubin -RSAPublicKey_out -inform DER -outform PEM \
     -out rsa-2048-public-key-legacy-form.pem
 ```
@@ -150,11 +150,11 @@ the `-noout` parameter suppresses this.
 openssl pkey -noout -text_pub -inform der -in <filename>
 ```
 
-For example, if you generated `p256-private-key.pk8` as described in the
+For example, if you generated `p256-private-key.p8` as described in the
 in the section on generating private keys, then given the command:
 
 ```sh
-openssl pkey -noout -text_pub -inform der -in p256-private-key.pk8
+openssl pkey -noout -text_pub -inform der -in p256-private-key.p8
 ```
 
 you'd see output like this (with a different value for `pub`, the public key):
@@ -171,11 +171,11 @@ ASN1 OID: prime256v1
 NIST CURVE: P-256
 ```
 
-As another example, if you generated `rsa-2048-private-key.pk8`
+As another example, if you generated `rsa-2048-private-key.p8`
 as described in the section on generating private keys, then this:
 
 ```sh
-openssl pkey -noout -text_pub -inform der -in rsa-2048-private-key.pk8
+openssl pkey -noout -text_pub -inform der -in rsa-2048-private-key.p8
 ``` 
 
 would output something like this (with a different `modulus` value):

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -113,12 +113,12 @@ openssl pkey -pubout -inform der -outform der \
     -out rsa-3072-public-key.spki
 ```
 
-## Extracting an RSA Public Key from the Private Key Without the SubjectPublicKeyInfo Metadata.
+## Extracting an RSA Public Key from the Private Key Without the SubjectPublicKeyInfo Metadata
 
 Above, we said we would only need `openssl pkey`, `openssl genpkey`, and
 `openssl pkcs8`, but that's only true if you don't need to output the
-legacy form of key. If you need the legacy form in binary (“DER”) format
-then can do the conversion following this example:
+legacy form of the public key. If you need the legacy form in binary (“DER”)
+format then can do the conversion following this example:
 
 ```sh
 openssl pkey -pubout -inform der -outform der \

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -76,7 +76,7 @@ openssl genpkey -algorithm RSA \
   openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.pk8
 ```
 
-## Extract the Public Key from the Private Key as a SubjectPublicKeyInfo.
+## Extracting the Public Key from the Private Key as a SubjectPublicKeyInfo.
 
 PKCS#8 files are self-describing, and PKCS#8 private key files contain the
 public key, so the public key can be extracted from the private key file:
@@ -113,7 +113,7 @@ openssl pkey -pubout -inform der -outform der \
     -out rsa-3072-public-key.spki
 ```
 
-## Extract an RSA Public Key from the Private Key Without the SubjectPublicKeyInfo Metadata.
+## Extracting an RSA Public Key from the Private Key Without the SubjectPublicKeyInfo Metadata.
 
 Above, we said we would only need `openssl pkey`, `openssl genpkey`, and
 `openssl pkcs8`, but that's only true if you don't need to output the

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -11,8 +11,10 @@ key files, some of which are specific to RSA (e.g. `openssl rsa` and
 `openssl pkey`, `openssl genpkey`, and `openssl pkcs8`, regardless of the type
 of key.
 
-The first section describes how to generate private keys. The second section
-describes how to inspect their metadata.
+The first section describes how to generate private keys. The second and
+third sections describe how to extract the public key from the generated
+private key. The last section describes how to inspect a private key's
+metadata.
 
 ## Generating Private Keys
 

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -131,7 +131,7 @@ The Base64 (“PEM”) form can be output following this example:
 openssl pkey -pubout -inform der -outform der \
     -in rsa-2048-private-key.pk8 | \
   openssl rsa -pubin -RSAPublicKey_out -inform DER -outform PEM \
-    -out rsa-2048-public-key-legacy-form.der
+    -out rsa-2048-public-key-legacy-form.pem
 ```
 
 ## Inspecting a Key's Public Metadata

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -111,8 +111,7 @@ openssl pkey -pubout -inform der -outform der \
     -out rsa-3072-public-key.spki
 ```
 
-## Extract an RSA Public Key from the Private Key Without the 
-SubjectPublicKeyInfo Metadata.
+## Extract an RSA Public Key from the Private Key Without the SubjectPublicKeyInfo Metadata.
 
 Above, we said we would only need `openssl pkey`, `openssl genpkey`, and
 `openssl pkcs8`, but that's only true if you don't need to output the

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -105,7 +105,14 @@ openssl pkey -pubout -inform der -outform der \
     -out rsa-2048-public-key.spki
 ```
 
-## Extract an RSA Public Key from the Private Key as "RSA PUBLIC KEY".
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in rsa-3072-private-key.pk8 \
+    -out rsa-3072-public-key.spki
+```
+
+## Extract an RSA Public Key from the Private Key Without the 
+SubjectPublicKeyInfo Metadata.
 
 Above, we said we would only need `openssl pkey`, `openssl genpkey`, and
 `openssl pkcs8`, but that's only true if you don't need to output the

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -74,6 +74,60 @@ openssl genpkey -algorithm RSA \
   openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.pk8
 ```
 
+## Extract the Public Key from the Private Key as a SubjectPublicKeyInfo.
+
+PKCS#8 files are self-describing, and PKCS#8 private key files contain the
+public key, so the public key can be extracted from the private key file:
+
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in <filename> \
+    -out <another-filename>
+```
+
+Examples:
+
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in p256-private-key.pk8 \
+    -out p256-public-key.spki
+```
+
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in p384-private-key.pk8 \
+    -out p384-public-key.spki
+```
+
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in rsa-2048-private-key.pk8 \
+    -out rsa-2048-public-key.spki
+```
+
+## Extract an RSA Public Key from the Private Key as "RSA PUBLIC KEY".
+
+Above, we said we would only need `openssl pkey`, `openssl genpkey`, and
+`openssl pkcs8`, but that's only true if you don't need to output the
+legacy form of key. If you need the legacy form in binary (“DER”) format
+then can do the conversion following this example:
+
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in rsa-2048-private-key.pk8 | \
+  openssl rsa -pubin -RSAPublicKey_out -inform DER -outform DER \
+    -out rsa-2048-public-key-legacy-form.der
+```
+
+The Base64 (“PEM”) form can be output following this example:
+
+```sh
+openssl pkey -pubout -inform der -outform der \
+    -in rsa-2048-private-key.pk8 | \
+  openssl rsa -pubin -RSAPublicKey_out -inform DER -outform PEM \
+    -out rsa-2048-public-key-legacy-form.der
+```
+
 ## Inspecting a Key's Public Metadata
 
 PKCS#8 files are self-describing, and PKCS#8 private key files contain the

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -7,7 +7,7 @@ based on OpenSSL.
 
 OpenSSL has a variety of commands that can be used to operate on private
 key files, some of which are specific to RSA (e.g. `openssl rsa` and
-`openssl genrsa`) or which have other limitations. Here we always use the
+`openssl genrsa`) or which have other limitations. Here we always use 
 `openssl pkey`, `openssl genpkey`, and `openssl pkcs8`, regardless of the type
 of key.
 

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -81,8 +81,8 @@ public key, so a single command can output all the public properties for
 any private key.
 
 **WARNING**: By default OpenSSL's command line tool will output the value
-of the private key, even when you ask for it to output the public key; the
-`-noout` parameter suppresses this.
+of the private key, even when you ask for it to output the public metadata;
+the `-noout` parameter suppresses this.
 
 ```sh
 openssl pkey -noout -text_pub -inform der -in <filename>

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -47,10 +47,9 @@ openssl genpkey -algorithm EC \
 
 ### RSA
 
-The key will have two primes (i.e. it will not be a multi-prime key). It will
-have public exponent 65537, which is the most interoperable (65537 is the
-default in the version of OpenSSL I have, but it is explicitly asked for just
-to be safe.).
+The key will have two primes (i.e. it will not be a multi-prime key), and
+public exponent 65537, which are by far the most interoperable parameters.
+Unless you have special requirements, generate a 2048-bit key.
 
 The key's algorithm identifier is `rsaEncryption` (`1.2.840.113549.1.1.1`),
 which is the most interoperable form. Almost all software will accept keys

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -8,7 +8,7 @@ based on OpenSSL.
 OpenSSL has a variety of commands that can be used to operate on private
 key files, some of which are specific to RSA (e.g. `openssl rsa` and
 `openssl genrsa`) or which have other limitations. Here we always use the
-`openssl pkey`, `openssl genpkey` and `openssl pkcs8`, regardless of the type
+`openssl pkey`, `openssl genpkey`, and `openssl pkcs8`, regardless of the type
 of key.
 
 The first section describes how to generate private keys. The second section

diff --git a/how-to-generate-and-use-private-keys-with-openssl-tool.md b/how-to-generate-and-use-private-keys-with-openssl-tool.md
@@ -89,8 +89,8 @@ of the private key, even when you ask for it to output the public key; the
 openssl pkey -noout -text_pub -inform der -in <filename>
 ```
 
-For example, if you generated `p256-private-key.pk8` using the command above,
-then given the command:
+For example, if you generated `p256-private-key.pk8` as described in the
+in the section on generating private keys, then given the command:
 
 ```sh
 openssl pkey -noout -text_pub -inform der -in p256-private-key.pk8
@@ -111,7 +111,7 @@ NIST CURVE: P-256
 ```
 
 As another example, if you generated `rsa-2048-private-key.pk8`
-as described above, then
+as described in the section on generating private keys, then this:
 
 ```sh
 openssl pkey -noout -text_pub -inform der -in rsa-2048-private-key.pk8

diff --git a/...enerate-private-keys-with-openssl-tool.md → ...and-use-private-keys-with-openssl-tool.md b/...enerate-private-keys-with-openssl-tool.md → ...and-use-private-keys-with-openssl-tool.md
diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -75,7 +75,7 @@ openssl genpkey -algorithm RSA \
   openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.pk8
 ```
 
-## Inspecting the Public Key Pair Metadata
+## Inspecting a Key's Public Metadata
 
 PKCS#8 files are self-describing, and PKCS#8 private key files contain the
 public key, so a single command can output all the public properties for

diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -77,9 +77,13 @@ openssl genpkey -algorithm RSA \
 
 ## Inspecting the Public Key Pair Metadata
 
-By default OpenSSL's command line tool will dump the contents of the private
-key, even when you ask for it to output the public key; the `-noout` parameter
-suppresses this.
+PKCS#8 files are self-describing, and PKCS#8 private key files contain the
+public key, so a single command can output all the public properties for
+any private key.
+
+**WARNING**: By default OpenSSL's command line tool will output the value
+of the private key, even when you ask for it to output the public key; the
+`-noout` parameter suppresses this.
 
 ```sh
 openssl pkey -noout -text_pub -inform der -in <filename>

diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -86,7 +86,13 @@ openssl pkey -noout -text_pub -inform der -in <filename>
 ```
 
 For example, if you generated `p256-private-key.pk8` using the command above,
-you'd see output like this (with a different value for `pub`):
+then given the command:
+
+```sh
+openssl pkey -noout -text_pub -inform der -in p256-private-key.pk8
+```
+
+you'd see output like this (with a different value for `pub`, the public key):
 
 ```text
 Public-Key: (256 bit)
@@ -100,7 +106,15 @@ ASN1 OID: prime256v1
 NIST CURVE: P-256
 ```
 
-For an RSA key, you'd see output like this (with a different `modulus` value):
+As another example, if you generated `rsa-2048-private-key.pk8`
+as described above, then
+
+```sh
+openssl pkey -noout -text_pub -inform der -in rsa-2048-private-key.pk8
+``` 
+
+would output something like this (with a different `modulus` value):
+
 ```text
 Public-Key: (2048 bit)
 Modulus:

diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -1,28 +1,33 @@
-# How to Generate Private Keys using OpenSSL's Command Line Tool
+# How to Generate & Use Private Keys using OpenSSL's Command Line Tool
 
-These commands generate private keys in unencrypted binary (not Base64 “PEM”)
-PKCS#8 format.
+These commands generate and use private keys in unencrypted binary
+(not Base64 “PEM”) PKCS#8 format. The PKCS#8 format is used here because
+it is the most interoperable format when dealing with software that isn't
+based on OpenSSL.
 
-The PKCS#8 format is used because it is the most interoperable format when
-dealing with software that isn't based on OpenSSL.
+OpenSSL has a variety of commands that can be used to operate on private
+key files, some of which are specific to RSA (e.g. `openssl rsa` and
+`openssl genrsa`) or which have other limitations. Here we always use the
+`openssl pkey`, `openssl genpkey` and `openssl pkcs8`, regardless of the type
+of key.
 
-OpenSSL has a variety of commands that can be used to generate
-private keys, some of which are specific to RSA (e.g. `openssl genrsa`) or
-which have other limitations. Here we always use the same commands
-`openssl genpkey` and `openssl pkcs8`.
+The first section describes how to generate private keys. The second section
+describes how to inspect their metadata.
+
+## Generating Private Keys
 
 Ed25519 isn't listed here because OpenSSL's command line utilities do not
 support Ed25519 keys yet.
 
-## ECC
+### ECC
 
 The key will use the named curve form, i.e. *the only correct form*, which
 unfortunately isn't the default form in all versions of OpenSSL.
 
 The algorithm identifier will be `id-ecPublicKey` (`1.2.840.10045.2.1`),
 which is what software for signing and verifying ECDSA signatures expects.
 
-### ECC P-256
+#### ECC P-256
 
 ```sh
 openssl genpkey -algorithm EC \
@@ -31,7 +36,7 @@ openssl genpkey -algorithm EC \
   openssl pkcs8 -topk8 -nocrypt -outform der > p256-private-key.pk8
 ```
 
-### ECC P-384
+#### ECC P-384
 
 ```sh
 openssl genpkey -algorithm EC \
@@ -40,7 +45,7 @@ openssl genpkey -algorithm EC \
   openssl pkcs8 -topk8 -nocrypt -outform der > p384-private-key.pk8
 ```
 
-## RSA
+### RSA
 
 The key will have two primes (i.e. it will not be a multi-prime key). It will
 have public exponent 65537, which is the most interoperable (65537 is the
@@ -52,7 +57,7 @@ which is the most interoperable form. Almost all software will accept keys
 marked as such for use in RSA encryption and for RSA PKCS#1 1.5 signatures and
 RSA-PSS signatures.
 
-### 2048-bit RSA 
+#### 2048-bit RSA 
 
 ```sh
 openssl genpkey -algorithm RSA \
@@ -61,11 +66,61 @@ openssl genpkey -algorithm RSA \
   openssl pkcs8 -topk8 -nocrypt -outform der > rsa-2048-private-key.pk8
 ```
 
-### 3072-bit RSA 
+#### 3072-bit RSA 
 
 ```sh
 openssl genpkey -algorithm RSA \
     -pkeyopt rsa_keygen_bits:3072 \
     -pkeyopt rsa_keygen_pubexp:65537 | \
   openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.pk8
 ```
+
+## Inspecting the Public Key Pair Metadata
+
+By default OpenSSL's command line tool will dump the contents of the private
+key, even when you ask for it to output the public key; the `-noout` parameter
+suppresses this.
+
+```sh
+openssl pkey -noout -text_pub -inform der -in <filename>
+```
+
+For example, if you generated `p256-private-key.pk8` using the command above,
+you'd see output like this (with a different value for `pub`):
+
+```text
+Public-Key: (256 bit)
+pub:
+    04:cf:0d:13:a3:a7:57:72:31:ea:1b:66:cf:40:21:
+    cd:54:f2:1f:4a:c4:f5:f2:fd:d2:8e:05:bc:7d:2b:
+    d0:99:d1:37:4c:d0:8d:2e:f6:54:d6:f0:44:98:db:
+    46:2f:73:e0:28:20:58:dd:66:1a:4c:9b:04:37:af:
+    3f:7a:f6:e7:24
+ASN1 OID: prime256v1
+NIST CURVE: P-256
+```
+
+For an RSA key, you'd see output like this (with a different `modulus` value):
+```text
+Public-Key: (2048 bit)
+Modulus:
+    00:b9:d7:af:84:fa:41:84:a5:f2:20:37:ec:8a:ff:
+    2d:b5:f7:8b:d8:c2:1e:71:4e:57:9a:e5:7c:63:98:
+    c4:95:0f:3a:69:4b:17:bf:cc:f4:88:76:61:59:ae:
+    c5:bb:7c:2c:43:d5:9c:79:8c:bd:45:a0:9c:9c:86:
+    93:3f:12:68:79:ee:7e:ad:cd:40:4f:61:ec:fc:42:
+    51:97:ca:b0:39:46:ba:38:1a:49:ef:3b:4d:0f:60:
+    b1:7f:8a:74:7c:de:56:a8:34:a7:f6:00:8f:35:ff:
+    b2:f6:0a:54:ce:da:19:74:ff:2a:99:63:ab:a7:f8:
+    0d:4e:29:16:a9:3d:8c:74:bb:1b:a5:f3:b1:89:a4:
+    e8:f0:37:7b:d3:e9:4b:5c:c3:f9:c5:3c:b8:c8:c7:
+    c0:af:39:48:18:75:5e:96:8b:7a:76:d9:ca:da:8d:
+    a7:af:5f:be:25:da:2a:09:73:7d:5e:4e:4d:70:92:
+    aa:16:a0:71:8d:73:22:ce:8a:ca:76:70:15:12:8d:
+    6d:35:77:5e:a9:cb:8b:b1:ac:65:12:e1:b7:87:d3:
+    40:15:22:1b:e7:80:a3:7b:1d:69:bc:37:08:bf:d8:
+    83:25:91:be:60:95:a7:68:f0:fd:3b:34:57:92:7e:
+    6a:e3:64:1d:55:79:9a:29:a0:a2:69:cb:4a:69:3b:
+    c1:4b
+Exponent: 65537 (0x10001)
+```
diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -16,9 +16,11 @@ support Ed25519 keys yet.
 
 ## ECC
 
-These commands generate keys that use the named curve form, i.e. *the only
-correct form*, which unfortunately isn't the default form in all versions
-of OpenSSL.
+The key will use the named curve form, i.e. *the only correct form*, which
+unfortunately isn't the default form in all versions of OpenSSL.
+
+The algorithm identifier will be `id-ecPublicKey` (`1.2.840.10045.2.1`),
+which is what software for signing and verifying ECDSA signatures expects.
 
 ### ECC P-256
 

diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -40,9 +40,15 @@ openssl genpkey -algorithm EC \
 
 ## RSA
 
-These commands use the public exponent 65537, and generate private keys that
-have two primes (not multi-prime keys). 65537 is the default in the version of
-OpenSSL I have, but it is explicitly asked for just to be safe.
+The key will have two primes (i.e. it will not be a multi-prime key). It will
+have public exponent 65537, which is the most interoperable (65537 is the
+default in the version of OpenSSL I have, but it is explicitly asked for just
+to be safe.).
+
+The key's algorithm identifier is `rsaEncryption` (`1.2.840.113549.1.1.1`),
+which is the most interoperable form. Almost all software will accept keys
+marked as such for use in RSA encryption and for RSA PKCS#1 1.5 signatures and
+RSA-PSS signatures.
 
 ### 2048-bit RSA 
 

diff --git a/how-to-generate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys-with-openssl-tool.md
@@ -41,7 +41,7 @@ openssl genpkey -algorithm EC \
 ## RSA
 
 These commands use the public exponent 65537, and generate private keys that
-use two primes (not multi-prime keys). 65537 is the default in the version of
+have two primes (not multi-prime keys). 65537 is the default in the version of
 OpenSSL I have, but it is explicitly asked for just to be safe.
 
 ### 2048-bit RSA 

diff --git a/how-to-generate-private-keys.md → ...enerate-private-keys-with-openssl-tool.md b/how-to-generate-private-keys.md → ...enerate-private-keys-with-openssl-tool.md
diff --git a/how-to-generate-private-keys.md b/how-to-generate-private-keys.md
@@ -0,0 +1,63 @@
+# How to Generate Private Keys using OpenSSL's Command Line Tool
+
+These commands generate private keys in unencrypted binary (not Base64 “PEM”)
+PKCS#8 format.
+
+The PKCS#8 format is used because it is the most interoperable format when
+dealing with software that isn't based on OpenSSL.
+
+OpenSSL has a variety of commands that can be used to generate
+private keys, some of which are specific to RSA (e.g. `openssl genrsa`) or
+which have other limitations. Here we always use the same commands
+`openssl genpkey` and `openssl pkcs8`.
+
+Ed25519 isn't listed here because OpenSSL's command line utilities do not
+support Ed25519 keys yet.
+
+## ECC
+
+These commands generate keys that use the named curve form, i.e. *the only
+correct form*, which unfortunately isn't the default form in all versions
+of OpenSSL.
+
+### ECC P-256
+
+```sh
+openssl genpkey -algorithm EC \
+    -pkeyopt ec_paramgen_curve:P-256 \
+    -pkeyopt ec_param_enc:named_curve | \
+  openssl pkcs8 -topk8 -nocrypt -outform der > p256-private-key.pk8
+```
+
+### ECC P-384
+
+```sh
+openssl genpkey -algorithm EC \
+    -pkeyopt ec_paramgen_curve:P-384 \
+    -pkeyopt ec_param_enc:named_curve |
+  openssl pkcs8 -topk8 -nocrypt -outform der > p384-private-key.pk8
+```
+
+## RSA
+
+These commands use the public exponent 65537, and generate private keys that
+use two primes (not multi-prime keys). 65537 is the default in the version of
+OpenSSL I have, but it is explicitly asked for just to be safe.
+
+### 2048-bit RSA 
+
+```sh
+openssl genpkey -algorithm RSA \
+    -pkeyopt rsa_keygen_bits:2048 \
+    -pkeyopt rsa_keygen_pubexp:65537 | \
+  openssl pkcs8 -topk8 -nocrypt -outform der > rsa-2048-private-key.pk8
+```
+
+### 3072-bit RSA 
+
+```sh
+openssl genpkey -algorithm RSA \
+    -pkeyopt rsa_keygen_bits:3072 \
+    -pkeyopt rsa_keygen_pubexp:65537 | \
+  openssl pkcs8 -topk8 -nocrypt -outform der > rsa-3072-private-key.pk8
+```
No results found