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Tcl

Encrypt Binary Content to a JWE

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.EncryptBd, which encrypts binary content held in a BinData and writes the resulting JWE into a StringBuilder.

Background. JWE (JSON Web Encryption) protects content with a content-encryption algorithm (the header enc value) while the content-encryption key is managed by the key-management algorithm (the header alg value). This example uses AES key wrapping with a symmetric wrapping key.

Chilkat Tcl Downloads

Tcl

load ./chilkat.dll

set success 0

set jwe [new_CkJwe]

#  Set the JWE protected header, specifying the key-management algorithm (alg) and the content-
#  encryption algorithm (enc).
set header [new_CkJsonObject]

CkJsonObject_UpdateString $header "alg" "A256KW"
CkJsonObject_UpdateString $header "enc" "A256GCM"
set success [CkJwe_SetProtectedHeader $jwe $header]
if {$success == 0} then {
    puts [CkJwe_lastErrorText $jwe]
    delete_CkJwe $jwe
    delete_CkJsonObject $header
    exit
}

#  The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key
#  from a secure source rather than hard-coding it.
set base64Key "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU="
set success [CkJwe_SetWrappingKey $jwe 0 $base64Key "base64"]
if {$success == 0} then {
    puts [CkJwe_lastErrorText $jwe]
    delete_CkJwe $jwe
    delete_CkJsonObject $header
    exit
}

#  Encrypt binary content held in a BinData, writing the resulting JWE into a StringBuilder.
set bdContent [new_CkBinData]

CkBinData_AppendString $bdContent "Binary content to encrypt." "utf-8"

set sbJwe [new_CkStringBuilder]

set success [CkJwe_EncryptBd $jwe $bdContent $sbJwe]
if {$success == 0} then {
    puts [CkJwe_lastErrorText $jwe]
    delete_CkJwe $jwe
    delete_CkJsonObject $header
    delete_CkBinData $bdContent
    delete_CkStringBuilder $sbJwe
    exit
}

puts [CkStringBuilder_getAsString $sbJwe]

delete_CkJwe $jwe
delete_CkJsonObject $header
delete_CkBinData $bdContent
delete_CkStringBuilder $sbJwe