(Go) Encrypt/Decrypt using PFX to produce -----BEGIN PKCS7----- ... -----END PKCS7-----

First we encrypt using a certificate + public key to produce output such as:

-----BEGIN PKCS7-----
MIIHPwYJKoZIhvcNAQcEoIIHMDCCBywC ...
...
...
-----END PKCS7-----

Chilkat Go Downloads Go Package for Windows, MacOS, Linux, Alpine Linux, Solaris

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    crypt := chilkat.NewCrypt2()

    // Specify the encryption to be used.
    // "pki" indicates "Public Key Infrastructure" and will create a PKCS7 encrypted (enveloped) message.
    crypt.SetCryptAlgorithm("pki")
    crypt.SetPkcs7CryptAlg("aes")
    crypt.SetKeyLength(128)
    crypt.SetOaepHash("sha256")
    crypt.SetOaepPadding(true)

    // A certificate is needed as the encryption key.
    // Althought the PFX contains the associated private key, we don't need it for encryption.
    // (A certificate usually contains the public key by default.)
    cert := chilkat.NewCert()
    success := cert.LoadPfxFile("qa_data/pfx/cert_test123.pfx","test123")
    if success != true {
        fmt.Println(cert.LastErrorText())
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        return
    }

    // Tell the crypt object to use the certificate.
    crypt.SetEncryptCert(cert)

    toBeEncrypted := "This string is to be encrypted."

    // Get the result in multi-line BASE64 MIME format.
    crypt.SetEncodingMode("base64_mime")

    encryptedStr := crypt.EncryptStringENC(toBeEncrypted)
    if success != true {
        fmt.Println(crypt.LastErrorText())
        crypt.DisposeCrypt2()
        cert.DisposeCert()
        return
    }

    // Make a "-----BEGIN PKCS7-----" ... "-----END PKCS7-----" sandwich...
    sb := chilkat.NewStringBuilder()
    sb.AppendLine("-----BEGIN PKCS7-----",true)
    sb.Append(*encryptedStr)
    sb.AppendLine("-----END PKCS7-----",true)

    outStr := sb.GetAsString()

    fmt.Println(*outStr)

    // Sample output:

    // -----BEGIN PKCS7-----
    // MIICXAYJKoZIhvcNAQcDoIICTTCCAkkCAQAxggH0MIIB8AIBADCBrDCBlzELMAkGA1UEBhMCR0Ix
    // GzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR
    // Q09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0
    // aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEB6M1ZwZdZU7LrAIdurulmUwOAYJKoZIhvcNAQEHMCug
    // DzANBglghkgBZQMEAgEFAKEYMBYGCSqGSIb3DQEBCDAJBgUrDgMCGgUABIIBAK/BZG/iXJ8az7zL
    // 8EQ77mc+oDPQ4w1hyytK2ip4djkPVvTfYhcoDQ+G/DBU+urJfrVBi5H9gmpXwYyfKlyUxBVRVEJl
    // V/V5QQi4JmNTFbmgWh5tp9zDS98l6A2Va4Zs0Wy/owGLfvwitlxd1dsfVAV2hmBYS24BMpNcty5/
    // 0atcKYmSou13G78ztTKdMy1tECgZy8kerMsPdDQbSxEZkT3KpQ8C5uEQqYF3bIVaeZzha/Ywieh/
    // tvO0T4aAmeJufwkNdVECmU7kuhnNaVPXknFl7jeibTl6zA/VcJKBKcIYT9FRC7KjdooI8q+jtQ/V
    // k6RP4POaowkFg1QWRPEWeqIwTAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBAgQQEEFQduqeJqXQXzy4
    // JpkoDoAgdldJDB9zEkpMpgr5/fR2iLvh5kC6BPfhOYjsawBY4Ok=
    // -----END PKCS7-----

    // ----------------------------------------------------------------------------------------
    // Let's Decrypt the above string.

    // Start with what was produced above..
    sb.Clear()
    bCrlf := true
    sb.AppendLine("-----BEGIN PKCS7-----",bCrlf)
    sb.AppendLine("MIICXAYJKoZIhvcNAQcDoIICTTCCAkkCAQAxggH0MIIB8AIBADCBrDCBlzELMAkGA1UEBhMCR0Ix",bCrlf)
    sb.AppendLine("GzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2FsZm9yZDEaMBgGA1UEChMR",bCrlf)
    sb.AppendLine("Q09NT0RPIENBIExpbWl0ZWQxPTA7BgNVBAMTNENPTU9ETyBSU0EgQ2xpZW50IEF1dGhlbnRpY2F0",bCrlf)
    sb.AppendLine("aW9uIGFuZCBTZWN1cmUgRW1haWwgQ0ECEB6M1ZwZdZU7LrAIdurulmUwOAYJKoZIhvcNAQEHMCug",bCrlf)
    sb.AppendLine("DzANBglghkgBZQMEAgEFAKEYMBYGCSqGSIb3DQEBCDAJBgUrDgMCGgUABIIBAK/BZG/iXJ8az7zL",bCrlf)
    sb.AppendLine("8EQ77mc+oDPQ4w1hyytK2ip4djkPVvTfYhcoDQ+G/DBU+urJfrVBi5H9gmpXwYyfKlyUxBVRVEJl",bCrlf)
    sb.AppendLine("V/V5QQi4JmNTFbmgWh5tp9zDS98l6A2Va4Zs0Wy/owGLfvwitlxd1dsfVAV2hmBYS24BMpNcty5/",bCrlf)
    sb.AppendLine("0atcKYmSou13G78ztTKdMy1tECgZy8kerMsPdDQbSxEZkT3KpQ8C5uEQqYF3bIVaeZzha/Ywieh/",bCrlf)
    sb.AppendLine("tvO0T4aAmeJufwkNdVECmU7kuhnNaVPXknFl7jeibTl6zA/VcJKBKcIYT9FRC7KjdooI8q+jtQ/V",bCrlf)
    sb.AppendLine("k6RP4POaowkFg1QWRPEWeqIwTAYJKoZIhvcNAQcBMB0GCWCGSAFlAwQBAgQQEEFQduqeJqXQXzy4",bCrlf)
    sb.AppendLine("JpkoDoAgdldJDB9zEkpMpgr5/fR2iLvh5kC6BPfhOYjsawBY4Ok=",bCrlf)
    sb.AppendLine("-----END PKCS7-----",bCrlf)

    decrypt := chilkat.NewCrypt2()
    decrypt.SetCryptAlgorithm("pki")

    // Use the same cert + private key from the PFX above.
    // For decryption, we need the private key.  Given that the certificate was loaded from a PFX,
    // we should already have it.
    success = decrypt.SetDecryptCert(cert)

    decrypt.SetEncodingMode("base64")
    decryptedText := decrypt.DecryptStringENC(*sb.GetBetween("-----BEGIN PKCS7-----","-----END PKCS7-----"))

    fmt.Println(*decryptedText)

    crypt.DisposeCrypt2()
    cert.DisposeCert()
    sb.DisposeStringBuilder()
    decrypt.DisposeCrypt2()